diff --git a/doc/Pacemaker_Explained/en-US/Ap-Changes.txt b/doc/Pacemaker_Explained/en-US/Ap-Changes.txt new file mode 100644 index 0000000000..1b4c76033a --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ap-Changes.txt @@ -0,0 +1,68 @@ +[appendix] + + +== What Changed in 1.0 == + +=== New === + +* Failure timeouts. See xref:s-failure-migration[] +* New section for resource and operation defaults. See xref:s-resource-defaults[] and xref:s-operation-defaults[] +* Tool for making offline configuration changes. See xref:s-config-sandboxes[] +* +Rules, instance_attributes, meta_attributes+ and sets of operations can be defined once and referenced in multiple places. See xref:s-reusing-config-elements[] +* The CIB now accepts XPath-based create/modify/delete operations. See the pass:[cibadmin] help text. +* Multi-dimensional colocation and ordering constraints. See xref:s-resource-sets-ordering[] and xref:s-resource-sets-collocation[] +* The ability to connect to the CIB from non-cluster machines. See xref:s-remote-connection[] +* Allow recurring actions to be triggered at known times. See xref:s-recurring-start[] + + +=== Changed === + +* Syntax +** All resource and cluster options now use dashes (-) instead of underscores (_) +** +master_slave+ was renamed to +master+ +** The +attributes+ container tag was removed +** The operation field +pre-req+ has been renamed +requires+ +** All operations must have an +interval+, +start+/+stop+ must have it set to zero +* The +stonith-enabled+ option now defaults to true. +* The cluster will refuse to start resources if +stonith-enabled+ is true (or unset) and no STONITH resources have been defined +* The attributes of colocation and ordering constraints were renamed for clarity. See xref:s-resource-ordering[] and xref:s-resource-colocation[] +* +resource-failure-stickiness+ has been replaced by +migration-threshold+. See xref:s-failure-migration[] +* The parameters for command-line tools have been made consistent +* Switched to indexterm:[>RelaxNG]RelaxNG schema validation and indexterm:[>libxml2]_libxml2_ parser +** id fields are now XML IDs which have the following limitations: +*** id's cannot contain colons (:) +*** id's cannot begin with a number +*** id's must be globally unique (not just unique for that tag) +** Some fields (such as those in constraints that refer to resources) are IDREFs. ++ +This means that they must reference existing resources or objects in +order for the configuration to be valid. Removing an object which is +referenced elsewhere will therefore fail. ++ +** The CIB representation, from which a MD5 digest is calculated to verify CIBs on the nodes, has changed. ++ +This means that every CIB update will require a full refresh on any +upgraded nodes until the cluster is fully upgraded to 1.0. This will +result in significant performance degradation and it is therefore +highly inadvisable to run a mixed 1.0/0.6 cluster for any longer than +absolutely necessary. ++ +* Ping node information no longer needs to be added to _ha.cf_. ++ +Simply include the lists of hosts in your ping resource(s). ++ +//// +Hack to force end list +//// + + + +=== Removed === + + +* Syntax +** It is no longer possible to set resource meta options as top-level + attributes. Use meta attributes instead. +** Resource and operation defaults are no longer read from + +crm_config+. See xref:s-resource-defaults[] and + xref:s-operation-defaults[] instead. diff --git a/doc/Pacemaker_Explained/en-US/Ap-Changes.xml b/doc/Pacemaker_Explained/en-US/Ap-Changes.xml deleted file mode 100644 index 4e7a3447fa..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ap-Changes.xml +++ /dev/null @@ -1,86 +0,0 @@ - - What Changed in 1.0 -
- New - - Failure timeouts. See - New section for resource and operation defaults. See and - Tool for making offline configuration changes. See - Rules, instance_attributes, meta_attributes and sets of operations can be defined once and referenced in multiple places. See - The CIB now accepts XPath-based create/modify/delete operations. See the cibadmin help text. - Multi-dimensional colocation and ordering constraints. See and - The ability to connect to the CIB from non-cluster machines. See - Allow recurring actions to be triggered at known times. See - -
-
- Changed - - - Syntax - - All resource and cluster options now use dashes (-) instead of underscores (_) - master_slave was renamed to master - The attributes container tag was removed - The operation field pre-req has been renamed requires - All operations must have an interval, start/stop must have it set to zero - - - The stonith-enabled option now defaults to true. - The cluster will refuse to start resources if stonith-enabled is true (or unset) and no STONITH resources have been defined - The attributes of colocation and ordering constraints were renamed for clarity. See and - resource-failure-stickiness has been replaced by migration-threshold. See - The parameters for command-line tools have been made consistent - - Switched to RelaxNGRelaxNG schema validation and libxml2libxml2 parser - - - id fields are now XML IDs which have the following limitations: - - id's cannot contain colons (:) - id's cannot begin with a number - id's must be globally unique (not just unique for that tag) - - - - - Some fields (such as those in constraints that refer to resources) are IDREFs. - This means that they must reference existing resources or objects in order for the configuration to be valid. - Removing an object which is referenced elsewhere will therefore fail. - - - - - The CIB representation, from which a MD5 digest is calculated to verify CIBs on the nodes, has changed. - This means that every CIB update will require a full refresh on any upgraded nodes until the cluster is fully upgraded to 1.0. - This will result in significant performance degradation and it is therefore highly inadvisable to run a mixed 1.0/0.6 cluster for any longer than absolutely necessary. - - - - - - Ping node information no longer needs to be added to ha.cf. Simply include the lists of hosts in your ping resource(s). - - -
-
- Removed - - - Syntax - - - - It is no longer possible to set resource meta options as top-level attributes. Use meta attributes instead. - - - - - Resource and operation defaults are no longer read from crm_config. See and instead. - - - - - -
- diff --git a/doc/Pacemaker_Explained/en-US/Ap-Install.txt b/doc/Pacemaker_Explained/en-US/Ap-Install.txt new file mode 100644 index 0000000000..463692ef43 --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ap-Install.txt @@ -0,0 +1,122 @@ +[appendix] + +== Installation == + +anchor:ap-install[Installation] + +[WARNING] +The following text may no longer be accurate in some places. + +=== Choosing a Cluster Stack === +indexterm:[Cluster Stack,choosing one] + +Ultimately the choice of cluster stack is a personal decision that +must be made in the context of you or your company's needs and +strategic direction. Pacemaker currently functions equally well with +both stacks. + +Here are some factors that may influence the decision: + +* SUSE/Novell, Red Hat and Oracle are all putting their collective + weight behind the Corosync cluster stack. + indexterm:[Cluster Stack,Corosync] + indexterm:[Corosync] +* Using Corosync gives your applications access to the following + additional cluster services +** distributed locking service +** extended virtual synchronization service +** cluster closed process group service +* It is likely that Pacemaker, at some point in the future, will make + use of some of these additional services not provided by Heartbeat + indexterm:[Cluster Stack,Heartbeat] + indexterm:[Heartbeat] + +=== Enabling Pacemaker === + +==== For Corosync ==== + +The Corosync configuration is normally located in +'/etc/corosync/corosync.conf' and an example for a machine with an +address of +1.2.3.4+ in a cluster communicating on port 1234 (without +peer authentication and message encryption) is shown below. + +.An example Corosync configuration file +[source,XML] +------- + totem { + version: 2 + secauth: off + threads: 0 + interface { + ringnumber: 0 + bindnetaddr: 1.2.3.4 + mcastaddr: 239.255.1.1 + mcastport: 1234 + } + } + logging { + fileline: off + to_syslog: yes + syslog_facility: daemon + } + amf { + mode: disabled + } + +------- + +The logging should be mostly obvious and the amf section refers to the +Availability Management Framework and is not covered in this document. + +The interesting part of the configuration is the totem section. This +is where we define how the node can communicate with the rest of the +cluster and what protocol version and options (including encryption +footnote:[ +Please consult the Corosync website (http://www.corosync.org/) and documentation for details on enabling encryption and peer authentication for the cluster. +] +) it should use. Beginners are encouraged to use the values shown and +modify the interface section based on their network. + +It is also possible to configure Corosync for an IPv6 based +environment. Simply configure +bindnetaddr+ and +mcastaddr+ with their +IPv6 equivalents, eg. + +.Example options for an IPv6 environment +[source,Bash] +------- + bindnetaddr: fec0::1:a800:4ff:fe00:20 + mcastaddr: ff05::1 +------- + +To tell Corosync to use the Pacemaker cluster manager, add the +following fragment to a functional Corosync configuration and restart +the cluster. + +.Configuration fragment for enabling Pacemaker under Corosync +[source,XML] +------- +aisexec { + user: root + group: root +} +service { + name: pacemaker + ver: 0 +} +------- + +The cluster needs to be run as root so that its child processes (the ++lrmd+ in particular) have sufficient privileges to perform the +actions requested of it. After all, a cluster manager that can't add +an IP address or start apache is of little use. + +The second directive is the one that actually instructs the cluster to +run Pacemaker. + +==== For Heartbeat ==== + +Add the following to a functional _ha.cf_ configuration file and restart Heartbeat: + +.Configuration fragment for enabling Pacemaker under Heartbeat +[source,Bash] +crm respawn diff --git a/doc/Pacemaker_Explained/en-US/Ap-Install.xml b/doc/Pacemaker_Explained/en-US/Ap-Install.xml deleted file mode 100644 index eb3f94a010..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ap-Install.xml +++ /dev/null @@ -1,107 +0,0 @@ - - Installation -
- Choosing a <indexterm significance="preferred"><primary>Cluster Stack</primary><secondary>choosing one</secondary></indexterm>Cluster Stack - Ultimately the choice of cluster stack is a personal decision that must be made in the context of you or your company's needs and strategic direction. Pacemaker currently functions equally well with both stacks. - Here are some factors that may influence the decision: - - - SUSE/Novell, Red Hat and Oracle are all putting their collective weight behind the Corosync cluster stack. - - - Cluster StackCorosync - CorosyncCorosync is an OSI Certified implementation of an industry standard (the Service Availability Forum Application Interface Specification). - - - Using Corosync gives your applications access to the following additional cluster services - - - checkpoint service - - - distributed locking service - - - extended virtual synchronization service - - - cluster closed process group service - - - - - It is likely that Pacemaker, at some point in the future, will make use of some of these additional services not provided by Heartbeat - - - To date, Pacemaker has received less real-world testing on Corosync than it has on - Cluster StackHeartbeat - HeartbeatHeartbeat. - - -
-
- Enabling Pacemaker -
- For Corosync - The Corosync configuration is normally located in /etc/corosync/corosync.conf and an example for a machine with an address of 1.2.3.4 in a cluster communicating on port 1234 (without peer authentication and message encryption) is shown below. - - An example Corosync configuration file - totem { - version: 2 - secauth: off - threads: 0 - interface { - ringnumber: 0 - bindnetaddr: 1.2.3.4 - mcastaddr: 239.255.1.1 - mcastport: 1234 - } - } - logging { - fileline: off - to_syslog: yes - syslog_facility: daemon - } - amf { - mode: disabled - } - - - The logging should be mostly obvious and the amf section refers to the Availability Management Framework and is not covered in this document. - The interesting part of the configuration is the totem section. This is where we define how the node can communicate with the rest of the cluster and what protocol version and options (including encryption - Please consult the Corosync website and documentation for details on enabling encryption and peer authentication for the cluster. - ) it should use. Beginners are encouraged to use the values shown and modify the interface section based on their network. - It is also possible to configure Corosync for an IPv6 based environment. Simply configure bindnetaddr and mcastaddr with their IPv6 equivalents, eg. - - Example options for an IPv6 environment - bindnetaddr: fec0::1:a800:4ff:fe00:20 - mcastaddr: ff05::1 - - - To tell Corosync to use the Pacemaker cluster manager, add the following fragment to a functional Corosync configuration and restart the cluster. - - Configuration fragment for enabling Pacemaker under Corosync - aisexec { - user: root - group: root -} -service { - name: pacemaker - ver: 0 -} - - - The cluster needs to be run as root so that its child processes (the lrmd in particular) have sufficient privileges to perform the actions requested of it. After all, a cluster manager that can't add an IP address or start apache is of little use. - The second directive is the one that actually instructs the cluster to run Pacemaker. -
-
- For Heartbeat - Add the following to a functional ha.cf configuration file and restart Heartbeat: - - Configuration fragment for enabling Pacemaker under Heartbeat - crm respawn - - -
-
- diff --git a/doc/Pacemaker_Explained/en-US/Ap-LSB.txt b/doc/Pacemaker_Explained/en-US/Ap-LSB.txt new file mode 100644 index 0000000000..3a8aaffc11 --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ap-LSB.txt @@ -0,0 +1,71 @@ +[appendix] + +== init-Script LSB Compliance == + +anchor:ap-lsb[LSB Compliance] + +The relevant part of +http://refspecs.freestandards.org/LSB_3.1.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html[LSB spec] +includes a description of all the return codes listed here. + +Assuming +some_service+ is configured correctly and currently not +active, the following sequence will help you determine if it is LSB +compatible: + +. Start (stopped): ++ +`/etc/init.d/some_service start ; echo "result: $?"` ++ + .. Did the service start? + .. Did the command print result: 0 (in addition to the regular output)? ++ +. Status (running): ++ +`/etc/init.d/some_service status ; echo "result: $?"` ++ + .. Did the script accept the command? + .. Did the script indicate the service was running? + .. Did the command print result: 0 (in addition to the regular output)? ++ +. Start (running): ++ +`/etc/init.d/some_service start ; echo "result: $?"` ++ + .. Is the service still running? + .. Did the command print result: 0 (in addition to the regular output)? ++ +. Stop (running): ++ +`/etc/init.d/some_service stop ; echo "result: $?"` ++ + .. Was the service stopped? + .. Did the command print result: 0 (in addition to the regular output)? ++ +. Status (stopped): ++ +`/etc/init.d/some_service status ; echo "result: $?"` ++ + .. Did the script accept the command? + .. Did the script indicate the service was not running? + .. Did the command print result: 3 (in addition to the regular output)? ++ +. Stop (stopped): ++ +`/etc/init.d/some_service stop ; echo "result: $?"` ++ + .. Is the service still stopped? + .. Did the command print result: 0 (in addition to the regular output)? ++ +. Status (failed): ++ +This step is not readily testable and relies on manual inspection of the script. ++ +The script can use one of the error codes (other than 3) listed in the +LSB spec to indicate that it is active but failed. This tells the +cluster that before moving the resource to another node, it needs to +stop it on the existing one first. + + +If the answer to any of the above questions is no, then the script is +not LSB compliant. Your options are then to either fix the script or +write an OCF agent based on the existing script. diff --git a/doc/Pacemaker_Explained/en-US/Ap-LSB.xml b/doc/Pacemaker_Explained/en-US/Ap-LSB.xml deleted file mode 100644 index 4a267335be..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ap-LSB.xml +++ /dev/null @@ -1,62 +0,0 @@ - - init-Script LSB Compliance - The relevant part of LSB init scriptsinit scriptscompatibilityLSB spec - - includes a description of all the return codes listed here. - - Assuming some_service is configured correctly and currently not active, the following sequence will help you determine if it is LSB compatible: - - - Start (stopped): - /etc/init.d/some_service start ; echo "result: $?" - - Did the service start? - Did the command print result: 0 (in addition to the regular output)? - - - Status (running): - /etc/init.d/some_service status ; echo "result: $?" - - Did the script accept the command? - Did the script indicate the service was running? - Did the command print result: 0 (in addition to the regular output)? - - - Start (running): - /etc/init.d/some_service start ; echo "result: $?" - - Is the service still running? - Did the command print result: 0 (in addition to the regular output)? - - - Stop (running): - /etc/init.d/some_service stop ; echo "result: $?" - - Was the service stopped? - Did the command print result: 0 (in addition to the regular output)? - - - Status (stopped): - /etc/init.d/some_service status ; echo "result: $?" - - Did the script accept the command? - Did the script indicate the service was not running? - Did the command print result: 3 (in addition to the regular output)? - - - - Stop (stopped): - /etc/init.d/some_service stop ; echo "result: $?" - - Is the service still stopped? - Did the command print result: 0 (in addition to the regular output)? - - - - Status (failed): - This step is not readily testable and relies on manual inspection of the script. - The script can use one of the error codes (other than 3) listed in the LSB spec to indicate that it is active but failed. This tells the cluster that before moving the resource to another node, it needs to stop it on the existing one first. - - - If the answer to any of the above questions is no, then the script is not LSB compliant. Your options are then to either fix the script or write an OCF agent based on the existing script. - diff --git a/doc/Pacemaker_Explained/en-US/Ap-OCF.txt b/doc/Pacemaker_Explained/en-US/Ap-OCF.txt new file mode 100644 index 0000000000..8b776450a9 --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ap-OCF.txt @@ -0,0 +1,260 @@ +[appendix] + +== More About OCF Resource Agents == + +anchor:ap-ocf[OCF Resource Agents] + +=== Location of Custom Scripts === + +indexterm:[OCF Resource Agents] +OCF Resource Agents are found in '/usr/lib/ocf/resource.d/+provider+'. + +When creating your own agents, you are encouraged to create a new +directory under _/usr/lib/ocf/resource.d/_ so that they are not +confused with (or overwritten by) the agents shipped with Heartbeat. + +So, for example, if you chose the provider name of bigCorp and wanted +a new resource named bigApp, you would create a script called +_/usr/lib/ocf/resource.d/bigCorp/bigApp_ and define a resource: + +[source,XML] + + +=== Actions === + +All OCF Resource Agents are required to implement the following actions + +.Required Actions for OCF Agents +[width="95%",cols="3m,3,7",options="header",align="center"] +|========================================================= +|Action +|Description +|Instructions + +|start +|Start the resource +indexterm:[start action] +indexterm:[action,start] +|Return 0 on success and an appropriate error code otherwise. Must not report success until the resource is fully active. + +|stop +|Stop the resource +indexterm:[stop action] +indexterm:[action,stop] +|Return 0 on success and an appropriate error code otherwise. Must not report success until the resource is fully stopped. + +|monitor +|Check the resource's state +indexterm:[monitor action] +indexterm:[action,monitor] +|Exit 0 if the resource is running, 7 if it is stopped, and anything else if it is failed. + +NOTE: The monitor script should test the state of the resource on the local machine only. + +|meta-data +|Describe the resource +indexterm:[meta-data action] +indexterm:[action,meta-data] +|Provide information about this resource as an XML snippet. Exit with 0. + +NOTE: This is *not* performed as root. + +|validate-all +|Verify the supplied parameters +indexterm:[validate-all action] +indexterm:[action,validate-all] +|Exit with 0 if parameters are valid, 2 if not valid, 6 if resource is not configured. + +|========================================================= + +Additional requirements (not part of the OCF specs) are placed on agents that will be used for advanced concepts like xref:s-resource-clone[clones] and xref:s-resource-multistate[multi-state] resources. + +.Optional Actions for OCF Agents +[width="95%",cols="2m,6,3",options="header",align="center"] +|========================================================= + +|Action +|Description +|Instructions + +|promote +|Promote the local instance of a multi-state resource to the master/primary state. +indexterm:[promote action] +indexterm:[action,promote] +|Return 0 on success + +|demote +|Demote the local instance of a multi-state resource to the slave/secondary state. +indexterm:[demote action] +indexterm:[action,demote] +|Return 0 on success + +|notify +|Used by the cluster to send the agent pre and post notification events telling the resource what has happened and will happen. +indexterm:[notify action] +indexterm:[action,notify] +|Must not fail. Must exit with 0 + +|========================================================= + +One action specified in the OCF specs is not currently used by the cluster: + +* +recover+ - a variant of the +start+ action, this should try to + recover a resource locally. + +Remember to use indexterm:[ocf-tester]`ocf-tester` to verify that your +new agent complies with the OCF standard properly. + +=== How are OCF Return Codes Interpreted? === + +The first thing the cluster does is to check the return code against +the expected result. If the result does not match the expected value, +then the operation is considered to have failed and recovery action is +initiated. + +There are three types of failure recovery: + +.Types of recovery performed by the cluster +[width="95%",cols="1m,4,4",options="header",align="center"] +|========================================================= + +|Type +|Description +|Action Taken by the Cluster + +|soft +indexterm:[soft error type] +indexterm:[error type,soft] +|A transient error occurred +|Restart the resource or move it to a new location + +|hard +indexterm:[hard error type] +indexterm:[error type,hard] +|A non-transient error that may be specific to the current node occurred +|Move the resource elsewhere and prevent it from being retried on the current node + +|fatal +indexterm:[fatal error type] +indexterm:[error type,fatal] +|A non-transient error that will be common to all cluster nodes (eg. a bad configuration was specified) +|Stop the resource and prevent it from being started on any cluster node + +|========================================================= + +Assuming an action is considered to have failed, the following table +outlines the different OCF return codes and the type of recovery the +cluster will initiate when it is received. + +anchor:s-ocf-return-codes[OCF Return Codes] + +.OCF Return Codes and their Recovery Types +[width="95%",cols="1m,5^m,6<,1m",options="header",align="center"] +|========================================================= + +|RC +|OCF Alias +|Description +|RT + +|indexterm:[return code,0]0 +|OCF_SUCCESS +|Success. The command completed successfully. This is the expected result for all start, stop, promote and demote commands. +indexterm:[OCF_SUCCESS] +indexterm:[Environment Variable,OCF_SUCCESS] +indexterm:[return code,OCF_SUCCESS] +|soft + +|indexterm:[return code,1]1 +|OCF_ERR_GENERIC +|Generic "there was a problem" error code. +indexterm:[OCF_ERR_,GENERIC] +indexterm:[Environment Variable,OCF_ERR_,GENERIC] +indexterm:[return code,OCF_ERR_,GENERIC] +|soft + +|indexterm:[return code,2]2 +|OCF_ERR_ARGS +|The resource's configuration is not valid on this machine. Eg. refers to a location/tool not found on the node. +indexterm:[OCF_ERR_,ARGS] +indexterm:[Environment Variable,OCF_ERR_,ARGS] +indexterm:[return code,OCF_ERR_,ARGS] +|hard + +|indexterm:[return code,3]3 +|OCF_ERR_UNIMPLEMENTED +|The requested action is not implemented. +indexterm:[OCF_ERR_,UNIMPLEMENTED] +indexterm:[Environment Variable,OCF_ERR_,UNIMPLEMENTED] +indexterm:[return code,OCF_ERR_,UNIMPLEMENTED] +|hard + +|indexterm:[return code,4]4 +|OCF_ERR_PERM +|The resource agent does not have sufficient privileges to complete the task. +indexterm:[OCF_ERR_,PERM] +indexterm:[Environment Variable,OCF_ERR_,PERM] +indexterm:[return code,OCF_ERR_,PERM] +|hard + +|indexterm:[return code,5]5 +|OCF_ERR_INSTALLED +|The tools required by the resource are not installed on this machine. +indexterm:[OCF_ERR_,INSTALLED] +indexterm:[Environment Variable,OCF_ERR_,INSTALLED] +indexterm:[return code,OCF_ERR_,INSTALLED] +|hard + +|indexterm:[return code,6]6 +|OCF_ERR_CONFIGURED +|The resource's configuration is invalid. Eg. required parameters are missing. +indexterm:[OCF_ERR_,CONFIGURED] +indexterm:[Environment Variable,OCF_ERR_,CONFIGURED] +indexterm:[return code,OCF_ERR_,CONFIGURED] +|fatal + +|indexterm:[return code,7]7 +|OCF_NOT_RUNNING +|The resource is safely stopped. The cluster will not attempt to stop a resource that returns this for any action. +indexterm:[OCF_NOT_RUNNING] +indexterm:[Environment Variable,OCF_NOT_RUNNING] +indexterm:[return code,OCF_NOT_RUNNING] +|N/A + +|indexterm:[return code,8]8 +|OCF_RUNNING_MASTER +|The resource is running in +Master+ mode. +indexterm:[OCF_RUNNING_MASTER] +indexterm:[Environment Variable,OCF_RUNNING_MASTER] +indexterm:[return code,OCF_RUNNING_MASTER] +|soft + +|indexterm:[return code,9]9 +|OCF_FAILED_MASTER +|The resource is in +Master+ mode but has failed. The resource will be demoted, stopped and then started (and possibly promoted) again. +indexterm:[OCF_FAILED_MASTER] +indexterm:[Environment Variable,OCF_FAILED_MASTER] +indexterm:[return code,OCF_FAILED_MASTER] +|soft + +|other +|NA +|Custom error code. +indexterm:[other return codes] +indexterm:[return code,other] +|soft + +|========================================================= + +Although counterintuitive, even actions that return 0 +(aka. +OCF_SUCCESS+) can be considered to have failed. + +=== Exceptions === + +* Non-recurring monitor actions (probes) that find a resource active + (or in Master mode) will not result in recovery action unless it is + also found active elsewhere +* The recovery action taken when a resource is found active more than + once is determined by the _multiple-active_ property of the resource +* Recurring actions that return +OCF_ERR_UNIMPLEMENTED+ + do not cause any type of recovery diff --git a/doc/Pacemaker_Explained/en-US/Ap-OCF.xml b/doc/Pacemaker_Explained/en-US/Ap-OCF.xml deleted file mode 100644 index 0003466ff5..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ap-OCF.xml +++ /dev/null @@ -1,254 +0,0 @@ - - More About OCF Resource Agents -
- Location of Custom Scripts - OCF Resource AgentsOCF Resource Agents are found in /usr/lib/ocf/resource.d/provider. - - When creating your own agents, you are encouraged to create a new directory under /usr/lib/ocf/resource.d/ so that they are not confused with (or overwritten by) the agents shipped with Heartbeat. - So, for example, if you chose the provider name of bigCorp and wanted a new resource named bigApp, you would create a script called /usr/lib/ocf/resource.d/bigCorp/bigApp and define a resource: - - <primitive id="custom-app" class="ocf" provider="bigCorp" type="bigApp"/> -
-
- Actions - All OCF Resource Agents are required to implement the following actions - - Required Actions for OCF Agents - - - - - - - Action - Description - Instructions - - - - - start action - actionstartstart - Start the resource - Return 0 on success and an appropriate error code otherwise. Must not report success until the resource is fully active. - - - stop action - actionstopstop - Stop the resource - Return 0 on success and an appropriate error code otherwise. Must not report success until the resource is fully stopped. - - - monitor action - actionmonitormonitor - Check the resource's state - - Exit 0 if the resource is running, 7 if it is stopped, and anything else if it is failed. - NOTE: The monitor script should test the state of the resource on the local machine only. - - - - meta-data action - actionmeta-datameta-data - Describe the resource - - Provide information about this resource as an XML snippet. Exit with 0. - NOTE: This is not performed as root. - - - - validate-all action - actionvalidate-allvalidate-all - Verify the supplied parameters - Exit with 0 if parameters are valid, 2 if not valid, 6 if resource is not configured. - -
- Additional requirements (not part of the OCF specs) are placed on agents that will be used for advanced concepts like clones and multi-state resources. - - Optional Actions for OCF Agents - - - - - - - Action - Description - Instructions - - - promote action - actionpromotepromote - Promote the local instance of a multi-state resource to the master/primary state. - Return 0 on success. - - - demote action - actiondemotedemote - Demote the local instance of a multi-state resource to the slave/secondary state. - Return 0 on success. - - - notify action - actionnotifynotify - Used by the cluster to send the agent pre and post notification events telling the resource what has happened and will happen. - Must not fail. Must exit with 0. - -
- One action specified in the OCF specs is not currently used by the cluster: - - recover - a variant of the start action, this should try to recover a resource locally. - - - Remember to use ocf-testerocf-tester to verify that your new agent complies with the OCF standard properly. -
-
- How are OCF Return Codes Interpreted? - The first thing the cluster does is to check the return code against the expected result. -If the result does not match the expected value, then the operation is considered to have failed and recovery action is initiated. - - There are three types of failure recovery: - - Types of recovery performed by the cluster - - - - - - - Type - Description - Action Taken by the Cluster - - - soft error type - error typesoftsoft - A transient error occurred - Restart the resource or move it to a new location - - - hard error type - error typehardhard - A non-transient error that may be specific to the current node occurred - Move the resource elsewhere and prevent it from being retried on the current node - - - fatal error type - error typefatalfatal - A non-transient error that will be common to all cluster nodes (eg. a bad configuration was specified) - Stop the resource and prevent it from being started on any cluster node - -
- Assuming an action is considered to have failed, the following table outlines the different OCF return codes and the type of recovery the cluster will initiate when it is received. - - OCF Return Codes and their Recovery Types - - - - - - - - RC - OCF Alias - Description - RT - - - return code00 - OCF_SUCCESS - Environment VariableOCF_SUCCESS - return codeOCF_SUCCESSOCF_SUCCESS - Success. The command completed successfully. This is the expected result for all start, stop, promote and demote commands. - soft - - - return code11 - OCF_ERR_GENERIC - Environment VariableOCF_ERR_GENERIC - return codeOCF_ERR_GENERIC - OCF_ERR_GENERIC - Generic "there was a problem" error code. - soft - - - return code22 - OCF_ERR_ARGS - Environment VariableOCF_ERR_ARGS - return codeOCF_ERR_ARGSOCF_ERR_ARGS - The resource's configuration is not valid on this machine. Eg. refers to a location/tool not found on the node. - hard - - - return code33 - OCF_ERR_UNIMPLEMENTED - Environment VariableOCF_ERR_UNIMPLEMENTED - return codeOCF_ERR_UNIMPLEMENTEDOCF_ERR_UNIMPLEMENTED - The requested action is not implemented. - hard - - - return code44 - OCF_ERR_PERM - Environment VariableOCF_ERR_PERM - return codeOCF_ERR_PERMOCF_ERR_PERM - The resource agent does not have sufficient privileges to complete the task. - hard - - - return code55 - OCF_ERR_INSTALLED - Environment VariableOCF_ERR_INSTALLED - return codeOCF_ERR_INSTALLEDOCF_ERR_INSTALLED - The tools required by the resource are not installed on this machine. - hard - - - return code66 - OCF_ERR_CONFIGURED - Environment VariableOCF_ERR_CONFIGURED - return codeOCF_ERR_CONFIGUREDOCF_ERR_CONFIGURED - The resource's configuration is invalid. Eg. required parameters are missing. - fatal - - - return code77 - OCF_NOT_RUNNING - Environment VariableOCF_NOT_RUNNING - return codeOCF_NOT_RUNNINGOCF_NOT_RUNNING - The resource is safely stopped. The cluster will not attempt to stop a resource that returns this for any action. - N/A - - - return code88 - OCF_RUNNING_MASTER - Environment VariableOCF_RUNNING_MASTER - return codeOCF_RUNNING_MASTEROCF_RUNNING_MASTER - The resource is running in Master mode. - soft - - - return code99 - OCF_FAILED_MASTER - Environment VariableOCF_FAILED_MASTER - return codeOCF_FAILED_MASTEROCF_FAILED_MASTER - The resource is in Master mode but has failed. The resource will be demoted, stopped and then started (and possibly promoted) again. - soft - - - other return codes - return codeotherother - NA - Custom error code. - soft - -
- Although counterintuitive, even actions that return 0 (aka. OCF_SUCCESS) can be considered to have failed. -This can happen when a resource that is expected to be in the Master state is found running as a Slave, or when a resource is found active on multiple machines.
Exceptions - - Non-recurring monitor actions (probes) that find a resource active (or in Master mode) will not result in recovery action unless it is also found active elsewhere - The recovery action taken when a resource is found active more than once is determined by the multiple-active property of the resource - Recurring actions that return OCF_ERR_UNIMPLEMENTED do not cause any type of recovery - -
- diff --git a/doc/Pacemaker_Explained/en-US/Ap-Samples.xml b/doc/Pacemaker_Explained/en-US/Ap-Samples.txt similarity index 65% rename from doc/Pacemaker_Explained/en-US/Ap-Samples.xml rename to doc/Pacemaker_Explained/en-US/Ap-Samples.txt index ebb7a9798c..bf17efe126 100644 --- a/doc/Pacemaker_Explained/en-US/Ap-Samples.xml +++ b/doc/Pacemaker_Explained/en-US/Ap-Samples.txt @@ -1,129 +1,141 @@ - Sample Configurations -
- An Empty Configuration - - An <indexterm significance="preferred"><primary>Empty Configuration</primary></indexterm><indexterm significance="preferred"><primary>Configuration</primary><secondary>Empty</secondary></indexterm>empty configuration - +[appendix] + +== Sample Configurations == + +=== Empty === + +indexterm:[Configuration,Empty] + +.An Empty Configuration +[source,XML] +------- + - ]]> - -
-
- A <indexterm significance="preferred"><primary>Simple</primary><secondary>Configuration</secondary></indexterm><indexterm significance="preferred"><primary>Configuration</primary><secondary>Simple</secondary></indexterm>Simple Configuration - - 2 nodes, some cluster options and a resource - +------- + +=== Simple === + +indexterm:[Configuration,Simple] + +.Simple Configuration - 2 nodes, some cluster options and a resource +[source,XML] +------- + - ]]> - - In this example, we have one resource (an IP address) that we check every five minutes and will run on host c001n01 until either the resource fails 10 times or the host shuts down. -
-
- An <indexterm significance="preferred"><primary>Advanced</primary><secondary>Configuration</secondary></indexterm><indexterm significance="preferred"><primary>Configuration</primary><secondary>Advanced</secondary></indexterm>Advanced Configuration - - - groups and clones with stonith - +------- + +In this example, we have one resource (an IP address) that we check +every five minutes and will run on host +c001n01+ until either the +resource fails 10 times or the host shuts down. + + +=== Advanced Configuration === +indexterm:[Configuration,Advanced] + +.Advanced configuration - groups and clones with stonith +[source,XML] +------- + - ]]> - -
- + +------- diff --git a/doc/Pacemaker_Explained/en-US/Ap-Upgrade-Config.txt b/doc/Pacemaker_Explained/en-US/Ap-Upgrade-Config.txt new file mode 100644 index 0000000000..8605f5f805 --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ap-Upgrade-Config.txt @@ -0,0 +1,140 @@ +[appendix] + +== Upgrading the Configuration from 0.6 == + +=== Preparation === +indexterm:[Upgrading the Configuration] +indexterm:[Configuration,Upgrading] + +indexterm:[Download,DTD] +indexterm:[DTD,Download] + +Download the latest +http://hg.clusterlabs.org/pacemaker/stable-1.0/file-raw/tip/xml/crm.dtd[DTD] +and ensure your configuration validates. + +=== Perform the upgrade === + +==== Upgrade the software ==== + +Refer to the appendix: xref:ap-upgrade[] + +==== Upgrade the Configuration ==== + +As XML is not the friendliest of languages, it is common for cluster +administrators to have scripted some of their activities. In such +cases, it is likely that those scripts will not work with the new 1.0 +syntax. + +In order to support such environments, it is actually possible to +continue using the old 0.6 syntax. + +The downside is, however, that not all the new features will be +available and there is a performance impact since the cluster must do +a non-persistent configuration upgrade before each transition. So +while using the old syntax is possible, it is not advisable to +continue using it indefinitely. + +Even if you wish to continue using the old syntax, it is advisable to +follow the upgrade procedure to ensure that the cluster is able to use +your existing configuration (since it will perform much the same task +internally). + +. Create a shadow copy to work with indexterm:[shadow copy,example for upgrading] ++ +[source,Bash] +----- +crm_shadow --create upgrade06 +----- +. Verify the configuration is valid indexterm:[Configuration,Verify]indexterm:[Verify,Configuration] ++ +[source,Bash] +----- +crm_verify --live-check +----- +. Fix any errors or warnings +. Perform the upgrade: ++ +[source,Bash] +----- +cibadmin --upgrade +----- +. If this step fails, there are three main possibilities: +.. The configuration was not valid to start with - go back to step 2 +.. The transformation failed - report a bug or mailto:pacemaker@oss.clusterlabs.org?subject=Transformation%20failed%20during%20upgrade[email the project] +.. The transformation was successful but produced an invalid result footnote:[ +The most common reason is ID values being repeated or invalid. Pacemaker 1.0 is much stricter regarding this type of validation. +] ++ +If the result of the transformation is invalid, you may see a number of errors from the validation library. If these are not helpful, visit http://clusterlabs.org/wiki/Validation_FAQ and/or try the procedure described below under xref:s-upgrade-config-manual[] ++ +. Check the changes ++ +[source,Bash] +----- +crm_shadow --diff +----- ++ +If at this point there is anything about the upgrade that you wish to fine-tune (for example, to change some of the automatic IDs) now is the time to do so. Since the shadow configuration is not in use by the cluster, it is safe to edit the file manually: ++ +[source,Bash] +----- +crm_shadow --edit +----- ++ +This will open the configuration in your favorite editor (whichever is specified by the standard +$EDITOR+ environment variable) ++ +. Preview how the cluster will react ++ +Test what the cluster will do when you upload the new configuration ++ +[source,Bash] +------ +crm_simulate --live-check --save-dotfile upgrade06.dot -S +graphviz upgrade06.dot +------ ++ +Verify that either no resource actions will occur or that you are +happy with any that are scheduled. If the output contains actions you +do not expect (possibly due to changes to the score calculations), you +may need to make further manual changes. See +xref:s-config-testing-changes[] for further details on how to interpret +the output of `crm_simulate` ++ +. Upload the changes ++ +[source,Bash] +----- +crm_shadow --commit upgrade06 --force +----- +If this step fails, something really strange has occurred. You should report a bug. + +==== Manually Upgrading the Configuration ==== + +anchor:s-upgrade-config-manual[Manually Upgrading the Configuration] +indexterm:[Configuration,Upgrade manually] +It is also possible to perform the configuration upgrade steps manually. To do this + +Locate the 'upgrade06.xsl' conversion script or download the latest +version from +https://github.com/ClusterLabs/pacemaker/tree/master/xml/upgrade06.xsl[Git] + +. Convert the XML blob: indexterm:[XML,Convert] ++ +[source,Bash] +----- +xsltproc /path/to/upgrade06.xsl config06.xml > config10.xml +----- ++ +. Locate the 'pacemaker.rng' script. +. Check the XML validity: indexterm:[Validate,XML]indexterm:[xmllint,Validate XML] ++ +[source,Bash] +----- +xmllint --relaxng /path/to/pacemaker.rng config10.xml +----- + +The advantage of this method is that it can be performed without the +cluster running and any validation errors should be more informative +(despite being generated by the same library!) since they include line +numbers. diff --git a/doc/Pacemaker_Explained/en-US/Ap-Upgrade-Config.xml b/doc/Pacemaker_Explained/en-US/Ap-Upgrade-Config.xml index a011eb97b6..b08a468e5e 100644 --- a/doc/Pacemaker_Explained/en-US/Ap-Upgrade-Config.xml +++ b/doc/Pacemaker_Explained/en-US/Ap-Upgrade-Config.xml @@ -1,96 +1,210 @@ - - Upgrading the Configuration from 0.6 -
- Preparation - Upgrading the Configuration - ConfigurationUpgrading - - DownloadDTD - DTDDownload - Download the latest DTD and ensure your configuration validates. -
-
- Perform the upgrade -
- Upgrade the software - Refer to the appendix: -
-
- Upgrade the Configuration - As XML is not the friendliest of languages, it is common for cluster administrators to have scripted some of their activities. In such cases, it is likely that those scripts will not work with the new 1.0 syntax. - In order to support such environments, it is actually possible to continue using the old 0.6 syntax. - The downside is, however, that not all the new features will be available and there is a performance impact since the cluster must do a non-persistent configuration upgrade before each transition. So while using the old syntax is possible, it is not advisable to continue using it indefinitely. - Even if you wish to continue using the old syntax, it is advisable to follow the upgrade procedure to ensure that the cluster is able to use your existing configuration (since it will perform much the same task internally). - - - Create a shadow copyexample for upgradingshadow copy to work with - crm_shadow --create upgrade06 - - - Verify the ConfigurationVerifyVerifyConfigurationconfiguration is valid - crm_verify --live-check - - - Fix any errors or warnings - - - Perform the upgrade: - cibadmin --upgrade - If this step fails, there are three main possibilities: - - The configuration was not valid to start with - go back to step 2 - The transformation failed - report a bug or email the project - The transformation was successful but produced an invalid result - The most common reason is ID values being repeated or invalid. Pacemaker 1.0 is much stricter regarding this type of validation. - - - If the result of the transformation is invalid, you may see a number of errors from the validation library. If these are not helpful, visit and/or try the procedure described below under . - - - Check the changes - crm_shadow --diff - If at this point there is anything about the upgrade that you wish to fine-tune (for example, to change some of the automatic IDs) now is the time to do so. Since the shadow configuration is not in use by the cluster, it is safe to edit the file manually: - crm_shadow --edit - This will open the configuration in your favorite editor (whichever is specified by the standard $EDITOR environment variable). - - - Preview how the cluster will react - Test what the cluster will do when you upload the new configuration - # ptest -VVVVV --live-check --save-dotfile upgrade06.dot -# graphviz upgrade06.dot - - Verify that either no resource actions will occur or that you are happy with any that are scheduled. - If the output contains actions you do not expect (possibly due to changes to the score calculations), you may need to make further manual changes. - See for further details on how to interpret the output of ptest. - - - - Upload the changes - crm_shadow --commit upgrade06 --force - If this step fails, something really strange has occurred. You should report a bug. - - -
-
- Manually Upgrading the Configuration - It is also possible to perform the ConfigurationUpgrade manuallyconfiguration upgrade steps manually. To do this - - - Locate the upgrade06.xsl conversion script or download the latest version from version control - - - Convert the XMLConvertXML blob: - xsltproc /path/to/upgrade06.xsl config06.xml > config10.xml - - - Locate the pacemaker.rng script. - - Check the ValidateXMLxmllintValidate XMLXML validity: - xmllint --relaxng /path/to/pacemaker.rng config10.xml - - - - The advantage of this method is that it can be performed without the cluster running and any validation errors should be more informative (despite being generated by the same library!) since they include line numbers. -
-
- + + + + + + + + +Upgrading the Configuration from 0.6 +
+Preparation + + Upgrading the Configuration + + + ConfigurationUpgrading + + + Upgrading + + + DownloadDTD + + + DTD + + + DTDDownload + + + Download + +Download the latest +DTD +and ensure your configuration validates. +
+
+Perform the upgrade +
+Upgrade the software +Refer to the appendix: +
+
+Upgrade the Configuration +As XML is not the friendliest of languages, it is common for cluster +administrators to have scripted some of their activities. In such +cases, it is likely that those scripts will not work with the new 1.0 +syntax. +In order to support such environments, it is actually possible to +continue using the old 0.6 syntax. +The downside is, however, that not all the new features will be +available and there is a performance impact since the cluster must do +a non-persistent configuration upgrade before each transition. So +while using the old syntax is possible, it is not advisable to +continue using it indefinitely. +Even if you wish to continue using the old syntax, it is advisable to +follow the upgrade procedure to ensure that the cluster is able to use +your existing configuration (since it will perform much the same task +internally). + + + +Create a shadow copy to work with + shadow copyexample for upgrading + + + example for upgrading + + +crm_shadow --create upgrade06 + + + +Verify the configuration is valid + ConfigurationVerify + + + Verify + + VerifyConfiguration + + + Configuration + + +crm_verify --live-check + + + +Fix any errors or warnings + + + + +Perform the upgrade: + +cibadmin --upgrade + + + +If this step fails, there are three main possibilities: + + + + +The configuration was not valid to start with - go back to step 2 + + + + +The transformation failed - report a bug or email the project + + + + +The transformation was successful but produced an invalid result +The most common reason is ID values being repeated or invalid. Pacemaker 1.0 is much stricter regarding this type of validation. + + +If the result of the transformation is invalid, you may see a number of errors from the validation library. If these are not helpful, visit http://clusterlabs.org/wiki/Validation_FAQ and/or try the procedure described below under + + + + + +Check the changes + +crm_shadow --diff +If at this point there is anything about the upgrade that you wish to fine-tune (for example, to change some of the automatic IDs) now is the time to do so. Since the shadow configuration is not in use by the cluster, it is safe to edit the file manually: +crm_shadow --edit +This will open the configuration in your favorite editor (whichever is specified by the standard $EDITOR environment variable) + + + +Preview how the cluster will react + +Test what the cluster will do when you upload the new configuration +crm_simulate --live-check --save-dotfile upgrade06.dot -S +graphviz upgrade06.dot +Verify that either no resource actions will occur or that you are +happy with any that are scheduled. If the output contains actions you +do not expect (possibly due to changes to the score calculations), you +may need to make further manual changes. See + for further details on how to interpret +the output of crm_simulate + + + +Upload the changes + +crm_shadow --commit upgrade06 --force + + +If this step fails, something really strange has occurred. You should report a bug. +
+
+Manually Upgrading the Configuration + + + ConfigurationUpgrade manually + + + Upgrade manually + +It is also possible to perform the configuration upgrade steps manually. To do this +Locate the upgrade06.xsl conversion script or download the latest +version from +Git + + + +Convert the XML blob: + XMLConvert + + + Convert + + +xsltproc /path/to/upgrade06.xsl config06.xml > config10.xml + + + +Locate the pacemaker.rng script. + + + + +Check the XML validity: + ValidateXML + + + XML + + xmllintValidate XML + + + Validate XML + + +xmllint --relaxng /path/to/pacemaker.rng config10.xml + + +The advantage of this method is that it can be performed without the +cluster running and any validation errors should be more informative +(despite being generated by the same library!) since they include line +numbers. +
+
+ + diff --git a/doc/Pacemaker_Explained/en-US/Ap-Upgrade.txt b/doc/Pacemaker_Explained/en-US/Ap-Upgrade.txt new file mode 100644 index 0000000000..1130607087 --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ap-Upgrade.txt @@ -0,0 +1,216 @@ +[appendix] +== Upgrading Cluster Software + +anchor:ap-upgrade[Upgrading Cluster Software] + +=== Version Compatibility === + +When releasing newer versions we take care to make sure we are +backwards compatible with older versions. While you will always be +able to upgrade from version x to x+1, in order to continue to produce +high quality software it may occasionally be necessary to drop +compatibility with older versions. + +There will always be an upgrade path from any series-2 release to any +other series-2 release. + +There are three approaches to upgrading your cluster software: + +* Complete Cluster Shutdown +* Rolling (node by node) +* Disconnect and Reattach + +Each method has advantages and disadvantages, some of which are listed +in the table below, and you should chose the one most appropriate to +your needs. + +.Summary of Upgrade Methodologies +[width="95%",cols="6*",options="header",align="center"] +|========================================================= + +|Type +|Available between all software versions +|Service Outage During Upgrade +|Service Recovery During Upgrade +|Exercises Failover Logic/Configuration +|Allows change of cluster stack type +indexterm:[Cluster Stack,switching between] +indexterm:[Changing Cluster Stack] +footnote:[ +For example, switching from Heartbeat to Corosync. Consult the +Heartbeat or Corosync documentation to see if upgrading them to a +newer version is also supported. +] + +|Shutdown +indexterm:[Upgrade,Shutdown] +indexterm:[Shutdown Upgrade] +|yes +|always +|N/A +|no +|yes + +|Rolling +indexterm:[Upgrade,Rolling] +indexterm:[Rolling Upgrade] +|no +|always +|yes +|yes +|no + +|Reattach +indexterm:[Upgrade,Reattach] +indexterm:[Reattach Upgrade] +|yes +|only due to failure +|no +|no +|yes + +|========================================================= + +=== Complete Cluster Shutdown === + +In this scenario one shuts down all cluster nodes and resources and +upgrades all the nodes before restarting the cluster. + +==== Procedure ==== +. On each node: +.. Shutdown the cluster stack (Heartbeat or Corosync) +.. Upgrade the Pacemaker software. + This may also include upgrading the cluster stack and/or the + underlying operating system. +.. Check the configuration manually or with the `crm_verify` tool if available. +. On each node: +.. Start the cluster stack. + This can be either Corosync or Heartbeat and does not need to be + the same as the previous cluster stack. + +=== Rolling (node by node) === + +In this scenario each node is removed from the cluster, upgraded and then brought back online until all nodes are running the newest version. + +[IMPORTANT] +=========== +This method is currently broken between Pacemaker 0.6.x and 1.0.x. + +Measures have been put into place to ensure rolling upgrades always +work for versions after 1.0.0. Please try one of the other upgrade +strategies. Detach/Reattach is a particularly good option for most +people. +=========== + +==== Procedure ==== + +On each node: +. Shutdown the cluster stack (Heartbeat or Corosync) +. Upgrade the Pacemaker software. This may also include upgrading the + cluster stack and/or the underlying operating system. +.. On the first node, check the configuration manually or with the + `crm_verify` tool if available. +.. Start the cluster stack. ++ +This must be the same type of cluster stack (Corosync or Heartbeat) +that the rest of the cluster is using. Upgrading Corosync/Heartbeat +may also be possible, please consult the documentation for those +projects to see if the two versions will be compatible. ++ +.. Repeat for each node in the cluster. + +==== Version Compatibility ==== + +.Version Compatibility Table +[width="95%",cols="2*",options="header",align="center"] +|========================================================= + +|Version being Installed +|Oldest Compatible Version + +|Pacemaker 1.0.x +|Pacemaker 1.0.0 + +|Pacemaker 0.7.x +|Pacemaker 0.6 or Heartbeat 2.1.3 + +|Pacemaker 0.6.x +|Heartbeat 2.0.8 + +|Heartbeat 2.1.3 (or less) +|Heartbeat 2.0.4 + +|Heartbeat 2.0.4 (or less) +|Heartbeat 2.0.0 + +|Heartbeat 2.0.0 +|None. Use an alternate upgrade strategy. + +|========================================================= + +==== Crossing Compatibility Boundaries ==== + +Rolling upgrades that cross compatibility boundaries must be preformed +in multiple steps. For example, to perform a rolling update from +Heartbeat 2.0.1 to Pacemaker 0.6.6 one must: + +. Perform a rolling upgrade from Heartbeat 2.0.1 to Heartbeat 2.0.4 +. Perform a rolling upgrade from Heartbeat 2.0.4 to Heartbeat 2.1.3 +. Perform a rolling upgrade from Heartbeat 2.1.3 to Pacemaker 0.6.6 + +=== Disconnect and Reattach === + +A variant of a complete cluster shutdown, but the resources are left +active and get re-detected when the cluster is restarted. + +==== Procedure ==== + +. Tell the cluster to stop managing services. ++ +This is required to allow the services to remain active after the +cluster shuts down. ++ +[source,Bash] +crm_attribute -t crm_config -n is-managed-default -v false ++ +. For any resource that has a value for +is-managed+, make sure it is +set to +false+ (so that the cluster will not stop it) ++ +[source,Bash] +crm_resource -t primitive -r $rsc_id -p is-managed -v false ++ +. On each node: +.. Shutdown the cluster stack (Heartbeat or Corosync) +.. Upgrade the cluster stack program - This may also include upgrading +the underlying operating system. +. Check the configuration manually or with the `crm_verify` tool if available. +. On each node: +.. Start the cluster stack. ++ +This can be either Corosync or Heartbeat and does not need to be the +same as the previous cluster stack. ++ +. Verify that the cluster re-detected all resources correctly. +. Allow the cluster to resume managing resources again: ++ +[source,Bash] +crm_attribute -t crm_config -n is-managed-default -v true ++ +. For any resource that has a value for +is-managed+ reset it to + +true+ (so the cluster can recover the service if it fails) if + desired: ++ +[source,Bash] +crm_resource -t primitive -r $rsc_id -p is-managed -v true + + +==== Notes ==== + +[IMPORTANT] +=========== +Always check your existing configuration is still compatible with the +version you are installing before starting the cluster. +=========== + +[NOTE] +The oldest version of the CRM to support this upgrade type was in Heartbeat 2.0.4 diff --git a/doc/Pacemaker_Explained/en-US/Ap-Upgrade.xml b/doc/Pacemaker_Explained/en-US/Ap-Upgrade.xml deleted file mode 100644 index b690b6acbd..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ap-Upgrade.xml +++ /dev/null @@ -1,258 +0,0 @@ - - Upgrading Cluster Software -
- Version Compatibility - When releasing newer versions we take care to make sure we are backwards compatible with older versions. While you will always be able to upgrade from version x to x+1, in order to continue to produce high quality software it may occasionally be necessary to drop compatibility with older versions. - There will always be an upgrade path from any series-2 release to any other series-2 release. - There are three approaches to upgrading your cluster software: - - Complete Cluster Shutdown - Rolling (node by node) - Disconnect and Reattach - - Each method has advantages and disadvantages, some of which are listed in the table below, and you should chose the one most appropriate to your needs. - - Summary of Upgrade Methodologies - - - - Type - Available between all software versions - Service Outage During Upgrade - Service Recovery During Upgrade - Exercises Failover Logic/Configuration - - Allows change of cluster stack type - - Cluster Stackswitching between - For example, switching from Heartbeat to Corosync. - Consult the Heartbeat or Corosync documentation to see if upgrading them to a newer version is also supported. - - - - - - - - - UpgradeShutdown - Shutdown Upgrade - Shutdown - yes - always - N/A - no - yes - - - - UpgradeRolling - Rolling Upgrade - Rolling - no - always - yes - yes - no - - - - UpgradeReattach - Reattach Upgrade - Reattach - yes - only due to failure - no - no - yes - - - -
-
-
- Complete Cluster Shutdown - In this scenario one shuts down all cluster nodes and resources and upgrades all the nodes before restarting the cluster. -
Procedure - - - On each node: - - - Shutdown the cluster stack (Heartbeat or Corosync) - - - - Upgrade the Pacemaker software. - This may also include upgrading the cluster stack and/or the underlying operating system. - - - - - - Check the configuration manually or with the crm_verify tool if available. - - - On each node: - - - - Start the cluster stack. - This can be either Corosync or Heartbeat and does not need to be the same as the previous cluster stack. - - - - - -
-
-
- Rolling (node by node) - In this scenario each node is removed from the cluster, upgraded and then brought back online until all nodes are running the newest version. - - - This method is currently broken between Pacemaker 0.6.x and 1.0.x. - - - Measures have been put into place to ensure rolling upgrades always work for versions after 1.0.0. - If there is sufficient demand, the work to repair 0.6 -> 1.0 compatibility will be carried out. - Otherwise, please try one of the other upgrade strategies. - Detach/Reattach is a particularly good option for most people. - - - -
- Procedure - On each node: - - - Shutdown the cluster stack (Heartbeat or Corosync) - - - Upgrade the Pacemaker software. This may also include upgrading the cluster stack and/or the underlying operating system. - - - On the first node, check the configuration manually or with the crm_verify tool if available. - - - - - - Start the cluster stack. - This must be the same type of cluster stack (Corosync or Heartbeat) that the rest of the cluster is using. - Upgrading Corosync/Heartbeat may also be possible, please consult the documentation for those projects to see if the two versions will be compatible. - - - - Repeat for each node in the cluster. -
-
- Version Compatibility - - Version Compatibility Table - - - - Version being Installed - Oldest Compatible Version - - - Pacemaker 1.0.x - Pacemaker 1.0.0 - - - Pacemaker 0.7.x - Pacemaker 0.6 or Heartbeat 2.1.3 - - - Pacemaker 0.6.x - Heartbeat 2.0.8 - - - Heartbeat 2.1.3 (or less) - Heartbeat 2.0.4 - - - Heartbeat 2.0.4 (or less) - Heartbeat 2.0.0 - - - Heartbeat 2.0.0 - None. Use an alternate upgrade strategy. - -
-
-
- Crossing Compatibility Boundaries - Rolling upgrades that cross compatibility boundaries must be preformed in multiple steps. For example, to perform a rolling update from Heartbeat 2.0.1 to Pacemaker 0.6.6 one must: - - Perform a rolling upgrade from Heartbeat 2.0.1 to Heartbeat 2.0.4 - Perform a rolling upgrade from Heartbeat 2.0.4 to Heartbeat 2.1.3 - Perform a rolling upgrade from Heartbeat 2.1.3 to Pacemaker 0.6.6 - -
-
-
- Disconnect and Reattach - A variant of a complete cluster shutdown, but the resources are left active and get re-detected when the cluster is restarted. -
- Procedure - - - - Tell the cluster to stop managing services. - This is required to allow the services to remain active after the cluster shuts down. - crm_attribute -t crm_config -n is-managed-default -v false - - - For any resource that has a value for is-managed, make sure it is set to false (so that the cluster will not stop it) - crm_resource -t primitive -r <rsc_id> -p is-managed -v false - - - On each node: - - - Shutdown the cluster stack (Heartbeat or Corosync) - - - Upgrade the cluster stack program - This may also include upgrading the underlying operating system. - - - - - Check the configuration manually or with the crm_verify tool if available. - - - On each node: - - - Start the cluster stack. - This can be either Corosync or Heartbeat and does not need to be the same as the previous cluster stack. - - - - - Verify that the cluster re-detected all resources correctly. - - - Allow the cluster to resume managing resources again: - crm_attribute -t crm_config -n is-managed-default -v true - - - For any resource that has a value for is-managed reset it to true (so the cluster can recover the service if it fails) if desired: - crm_resource -t primitive -r <rsc_id> -p is-managed -v true - - -
-
- Notes - - Always check your existing configuration is still compatible with the version you are installing before starting the cluster. - - - - The oldest version of the CRM to support this upgrade type was in Heartbeat 2.0.4 - -
-
- diff --git a/doc/Pacemaker_Explained/en-US/Book_Info.xml b/doc/Pacemaker_Explained/en-US/Book_Info.xml index 8255c99d68..93f1783439 100644 --- a/doc/Pacemaker_Explained/en-US/Book_Info.xml +++ b/doc/Pacemaker_Explained/en-US/Book_Info.xml @@ -1,37 +1,40 @@ Configuration Explained An A-Z guide to Pacemaker's Configuration Options Pacemaker 1.1 1 0 The purpose of this document is to definitively explain the concepts used to configure Pacemaker. To achieve this, it will focus exclusively on the XML syntax used to configure the CIB. - For those that are allergic to XML, Pacemaker comes with a cluster shell; a Python based GUI exists, too, however these tools will not be covered at all in this document + For those that are allergic to XML, there exist several unified shells + and GUIs for Pacemaker. However these tools will not be covered at all + in this document I hope, however, that the concepts explained here make the functionality of these tools more easily understood. , precisely because they hide the XML. Additionally, this document is NOT a step-by-step how-to guide for configuring a specific clustering scenario. Although such guides exist, the purpose of this document is to provide an understanding of the building blocks that can be used to construct any type of Pacemaker cluster. + Try the Clusters from Scratch document instead. diff --git a/doc/Pacemaker_Explained/en-US/Ch-Basics.txt b/doc/Pacemaker_Explained/en-US/Ch-Basics.txt index b23597679e..c165dcdf39 100644 --- a/doc/Pacemaker_Explained/en-US/Ch-Basics.txt +++ b/doc/Pacemaker_Explained/en-US/Ch-Basics.txt @@ -1,349 +1,349 @@ = Configuration Basics = == Configuration Layout == The cluster is written using XML notation and divided into two main sections: configuration and status. The status section contains the history of each resource on each node and based on this data, the cluster can construct the complete current state of the cluster. The authoritative source for the status section is the local resource manager (lrmd) process on each cluster node and the cluster will occasionally repopulate the entire section. For this reason it is never written to disk and administrators are advised against modifying it in any way. The configuration section contains the more traditional information like cluster options, lists of resources and indications of where they should be placed. The configuration section is the primary focus of this document. The configuration section itself is divided into four parts: * Configuration options (called +crm_config+) * Nodes * Resources * Resource relationships (called +constraints+) .An empty configuration [source,XML] ------- ------- == The Current State of the Cluster == Before one starts to configure a cluster, it is worth explaining how to view the finished product. For this purpose we have created the -pass:[crm_mon] utility that will display the +`crm_mon` utility that will display the current state of an active cluster. It can show the cluster status by node or by resource and can be used in either single-shot or dynamically-updating mode. There are also modes for displaying a list of the operations performed (grouped by node and resource) as well as information about failures. Using this tool, you can examine the state of the cluster for irregularities and see how it responds when you cause or simulate failures. Details on all the available options can be obtained using the -pass:[crm_mon --help] command. +`crm_mon --help` command. .Sample output from crm_mon ------- ============ Last updated: Fri Nov 23 15:26:13 2007 Current DC: sles-3 (2298606a-6a8c-499a-9d25-76242f7006ec) 3 Nodes configured. 5 Resources configured. ============ Node: sles-1 (1186dc9a-324d-425a-966e-d757e693dc86): online 192.168.100.181 (heartbeat::ocf:IPaddr): Started sles-1 192.168.100.182 (heartbeat:IPaddr): Started sles-1 192.168.100.183 (heartbeat::ocf:IPaddr): Started sles-1 rsc_sles-1 (heartbeat::ocf:IPaddr): Started sles-1 child_DoFencing:2 (stonith:external/vmware): Started sles-1 Node: sles-2 (02fb99a8-e30e-482f-b3ad-0fb3ce27d088): standby Node: sles-3 (2298606a-6a8c-499a-9d25-76242f7006ec): online rsc_sles-2 (heartbeat::ocf:IPaddr): Started sles-3 rsc_sles-3 (heartbeat::ocf:IPaddr): Started sles-3 child_DoFencing:0 (stonith:external/vmware): Started sles-3 ------- .Sample output from crm_mon -n ------- ============ Last updated: Fri Nov 23 15:26:13 2007 Current DC: sles-3 (2298606a-6a8c-499a-9d25-76242f7006ec) 3 Nodes configured. 5 Resources configured. ============ Node: sles-1 (1186dc9a-324d-425a-966e-d757e693dc86): online Node: sles-2 (02fb99a8-e30e-482f-b3ad-0fb3ce27d088): standby Node: sles-3 (2298606a-6a8c-499a-9d25-76242f7006ec): online Resource Group: group-1 192.168.100.181 (heartbeat::ocf:IPaddr): Started sles-1 192.168.100.182 (heartbeat:IPaddr): Started sles-1 192.168.100.183 (heartbeat::ocf:IPaddr): Started sles-1 rsc_sles-1 (heartbeat::ocf:IPaddr): Started sles-1 rsc_sles-2 (heartbeat::ocf:IPaddr): Started sles-3 rsc_sles-3 (heartbeat::ocf:IPaddr): Started sles-3 Clone Set: DoFencing child_DoFencing:0 (stonith:external/vmware): Started sles-3 child_DoFencing:1 (stonith:external/vmware): Stopped child_DoFencing:2 (stonith:external/vmware): Started sles-1 ------- The DC (Designated Controller) node is where all the decisions are made and if the current DC fails a new one is elected from the remaining cluster nodes. The choice of DC is of no significance to an administrator beyond the fact that its logs will generally be more interesting. == How Should the Configuration be Updated? == There are three basic rules for updating the cluster configuration: * Rule 1 - Never edit the cib.xml file manually. Ever. I'm not making this up. * Rule 2 - Read Rule 1 again. * Rule 3 - The cluster will notice if you ignored rules 1 & 2 and refuse to use the configuration. Now that it is clear how NOT to update the configuration, we can begin to explain how you should. The most powerful tool for modifying the configuration is the +cibadmin+ command which talks to a running cluster. With +cibadmin+, the user can query, add, remove, update or replace any part of the configuration; all changes take effect immediately, so there is no need to perform a reload-like operation. The simplest way of using cibadmin is to use it to save the current configuration to a temporary file, edit that file with your favorite text or XML editor and then upload the revised configuration. .Safely using an editor to modify the cluster configuration [source,Bash] -------- # cibadmin --query > tmp.xml # vi tmp.xml # cibadmin --replace --xml-file tmp.xml -------- Some of the better XML editors can make use of a Relax NG schema to help make sure any changes you make are valid. The schema describing the configuration can normally be found in pass:[/usr/lib/heartbeat/pacemaker.rng] on most systems. If you only wanted to modify the resources section, you could instead do .Safely using an editor to modify a subsection of the cluster configuration [source,Bash] -------- # cibadmin --query --obj_type resources > tmp.xml # vi tmp.xml # cibadmin --replace --obj_type resources --xml-file tmp.xml -------- to avoid modifying any other part of the configuration. == Quickly Deleting Part of the Configuration == Identify the object you wish to delete. Eg. run .Searching for STONITH related configuration items [source,Bash] -------- # cibadmin -Q | grep stonith -------- Next identify the resource's tag name and id (in this case we'll choose +primitive+ and +child_DoFencing+). Then simply execute: -pass:[cibadmin --delete --crm_xml '<primitive id="child_DoFencing"/>'] +`cibadmin --delete --crm_xml '<primitive id="child_DoFencing"/>'` == Updating the Configuration Without Using XML == Some common tasks can also be performed with one of the higher level tools that avoid the need to read or edit XML. To enable stonith for example, one could run: -pass:[crm_attribute --attr-name stonith-enabled --attr-value true] +`crm_attribute --attr-name stonith-enabled --attr-value true` Or, to see if +somenode+ is allowed to run resources, there is: -pass:[crm_standby --get-value --node-uname somenode] +`crm_standby --get-value --node-uname somenode` Or, to find the current location of +my-test-rsc+, one can use: -pass:[crm_resource --locate --resource my-test-rsc] +`crm_resource --locate --resource my-test-rsc` [[s-config-sandboxes]] == Making Configuration Changes in a Sandbox == Often it is desirable to preview the effects of a series of changes before updating the configuration atomically. For this purpose we -have created pass:[crm_shadow] which creates a +have created `crm_shadow` which creates a "shadow" copy of the configuration and arranges for all the command line tools to use it. -To begin, simply invoke pass:[crm_shadow] and give +To begin, simply invoke `crm_shadow` and give it the name of a configuration to create footnote:[Shadow copies are identified with a name, making it possible to have more than one.] ; be sure to follow the simple on-screen instructions. WARNING: Read the above carefully, failure to do so could result in you destroying the cluster's active configuration! .Creating and displaying the active sandbox [source,Bash] -------- # crm_shadow --create test Setting up shadow instance Type Ctrl-D to exit the crm_shadow shell shadow[test]: shadow[test] # crm_shadow --which test -------- From this point on, all cluster commands will automatically use the shadow copy instead of talking to the cluster's active configuration. Once you have finished experimenting, you can either commit the changes, or discard them as shown below. Again, be sure to follow the on-screen instructions carefully. -For a full list of pass:[crm_shadow] options and +For a full list of `crm_shadow` options and commands, invoke it with the --help option. .Using a sandbox to make multiple changes atomically [source,Bash] -------- shadow[test] # crm_failcount -G -r rsc_c001n01 name=fail-count-rsc_c001n01 value=0 shadow[test] # crm_standby -v on -n c001n02 shadow[test] # crm_standby -G -n c001n02 name=c001n02 scope=nodes value=on shadow[test] # cibadmin --erase --force shadow[test] # cibadmin --query shadow[test] # crm_shadow --delete test --force Now type Ctrl-D to exit the crm_shadow shell shadow[test] # exit # crm_shadow --which No shadow instance provided # cibadmin -Q -------- Making changes in a sandbox and verifying the real configuration is untouched [[s-config-testing-changes]] == Testing Your Configuration Changes == We saw previously how to make a series of changes to a "shadow" copy of the configuration. Before loading the changes back into the -cluster (eg. pass:[crm_shadow --commit mytest ---force]), it is often advisable to simulate the effect of -the changes with +ptest+, eg. +cluster (eg. `crm_shadow --commit mytest +--force`), it is often advisable to simulate the effect of +the changes with +crm_simulate+, eg. -pass:[ptest --live-check -VVVVV --save-graph tmp.graph --save-dotfile tmp.dot] +`crm_simulate --live-check -VVVVV --save-graph tmp.graph --save-dotfile tmp.dot` The tool uses the same library as the live cluster to show what it would have done given the supplied input. It's output, in addition to a significant amount of logging, is stored in two files +tmp.graph+ and +tmp.dot+, both are representations of the same thing -- the cluster's response to your changes. In the graph file is stored the complete transition, containing a list of all the actions, their parameters and their pre-requisites. Because the transition graph is not terribly easy to read, the tool also generates a Graphviz dot-file representing the same information. == Interpreting the Graphviz output == * Arrows indicate ordering dependencies * Dashed-arrows indicate dependencies that are not present in the transition graph * Actions with a dashed border of any color do not form part of the transition graph * Actions with a green border form part of the transition graph * Actions with a red border are ones the cluster would like to execute but cannot run * Actions with a blue border are ones the cluster does not feel need to be executed * Actions with orange text are pseudo/pretend actions that the cluster uses to simplify the graph * Actions with black text are sent to the LRM * Resource actions have text of the form pass:[rsc]_pass:[action]_pass:[interval] pass:[node] * Any action depending on an action with a red border will not be able to execute. * Loops are _really_ bad. Please report them to the development team. === Small Cluster Transition === image::images/Policy-Engine-small.png["An example transition graph as represented by Graphviz",width="16cm",height="6cm",align="center"] In the above example, it appears that a new node, +node2+, has come online and that the cluster is checking to make sure +rsc1+, +rsc2+ and +rsc3+ are not already running there (Indicated by the +*_monitor_0+ entries). Once it did that, and assuming the resources were not active there, it would have liked to stop +rsc1+ and +rsc2+ on +node1+ and move them to +node2+. However, there appears to be some problem and the cluster cannot or is not permitted to perform the stop actions which implies it also cannot perform the start actions. For some reason the cluster does not want to start +rsc3+ anywhere. -For information on the options supported by ptest, use -pass:[ptest --help]. +For information on the options supported by `crm_simulate`, use +the `--help` option. === Complex Cluster Transition === image::images/Policy-Engine-big.png["Another, slightly more complex, transition graph that you're not expected to be able to read",width="16cm",height="20cm",align="center"] == Do I Need to Update the Configuration on all Cluster Nodes? == No. Any changes are immediately synchronized to the other active members of the cluster. To reduce bandwidth, the cluster only broadcasts the incremental updates that result from your changes and uses MD5 checksums to ensure that each copy is completely consistent. diff --git a/doc/Pacemaker_Explained/en-US/Ch-Constraints.txt b/doc/Pacemaker_Explained/en-US/Ch-Constraints.txt new file mode 100644 index 0000000000..e93edd1adc --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ch-Constraints.txt @@ -0,0 +1,546 @@ += Resource Constraints = + +== Scores == +indexterm:[Resource,Constraints] +indexterm:[Constraints,for Resources] + +Scores of all kinds are integral to how the cluster works. +Practically everything from moving a resource to deciding which +resource to stop in a degraded cluster is achieved by manipulating +scores in some way. + +Scores are calculated on a per-resource basis and any node with a +negative score for a resource can't run that resource. After +calculating the scores for a resource, the cluster then chooses the +node with the highest one. + +=== Infinity Math === + ++INFINITY+ is currently defined as 1,000,000 and addition/subtraction +with it follows these three basic rules: + +* Any value + +INFINITY+ = +INFINITY+ +* Any value - +INFINITY+ = -+INFINITY+ +* +INFINITY+ - +INFINITY+ = -+INFINITY+ + +== Deciding Which Nodes a Resource Can Run On == + +There are two alternative strategies for specifying which nodes a +resources can run on. One way is to say that by default they can run +anywhere and then create location constraints for nodes that are not +allowed. The other option is to have nodes "opt-in"... to start with +nothing able to run anywhere and selectively enable allowed nodes. + +=== Options === + +.Options for Simple Location Constraints +[width="95%",cols="1m,5<",options="header",align="center"] +|========================================================= + +|Field +|Description + +|id +indexterm:[id,Constraint Field] +indexterm:[Constraint Field,id] +|A unique name for the constraint + +|rsc, +indexterm:[rsc Constraint Field] +indexterm:[Constraint Field,rsc] +|A resource name + +|node +indexterm:[Node,Constraint Field] +indexterm:[Constraint Field,node] +|A node's uname + +|score +indexterm:[score,Constraint Field] +indexterm:[Constraint Field,score] +|Positive values indicate the resource should run on this +. node. Negative values indicate the resource should not run on this + node. Values of +/- +INFINITY+ change "should"/"should not" to + "must"/"must not". + +|========================================================= + +=== Asymmetrical "Opt-In" Clusters === +indexterm:[Asymmetrical Opt-In Clusters] +indexterm:[Cluster Type,Asymmetrical Opt-In] + + +To create an opt-in cluster, start by preventing resources from +running anywhere by default: + +[source,Bash] +crm_attribute --attr-name symmetric-cluster --attr-value false + +Then start enabling nodes. The following fragment says that the web +server prefers +sles-1+, the database prefers +sles-2+ and both can +fail over to +sles-3+ if their most preferred node fails. + +.Example set of opt-in location constraints +[source,XML] +------- + + + + + + +------- + +=== Symmetrical "Opt-Out" Clusters === +indexterm:[Symmetrical Opt-Out Clusters] +indexterm:[Cluster Type,Symmetrical Opt-Out] + +To create an opt-out cluster, start by allowing resources to run +anywhere by default: + +[source,Bash] +crm_attribute --attr-name symmetric-cluster --attr-value true + +Then start disabling nodes. The following fragment is the equivalent +of the above opt-in configuration. + +.Example set of opt-out location constraints +[source,XML] +------- + + + + + + +------- + +Whether you should choose opt-in or opt-out depends both on your +personal preference and the make-up of your cluster. If most of your +resources can run on most of the nodes, then an opt-out arrangement is +likely to result in a simpler configuration. On the other-hand, if +most resources can only run on a small subset of nodes an opt-in +configuration might be simpler. + +=== What if Two Nodes Have the Same Score === + +anchor:node-score-equal[What if Two Nodes Have the Same Score] +If two nodes have the same score, then the cluster will choose one. +This choice may seem random and may not be what was intended, however +the cluster was not given enough information to know any better. + +.Example of two resources that prefer two nodes equally +[source,XML] +------- + + + + + + + +------- + +In the example above, assuming no other constraints and an inactive +cluster, Webserver would probably be placed on sles-1 and Database on +sles-2. It would likely have placed Webserver based on the node's +uname and Database based on the desire to spread the resource load +evenly across the cluster. However other factors can also be involved +in more complex configurations. + +== Specifying in which Order Resources Should Start/Stop == + +anchor:s-resource-ordering[Resource Start Ordering] +The way to specify the order in which resources should start is by +creating +rsc_order+ constraints. + +.Properties of an Ordering Constraint +[width="95%",cols="1m,5<",options="header",align="center"] +|========================================================= + +|Field +|Description + +|id +|A unique name for the constraint + +|first +|The name of a resource that must be started before the +then+ + resource is allowed to. + +|then +|The name of a resource. This resource will start after the +first+ resource. + +|score +|If greater than zero, the constraint is mandatory. Otherwise it is + only a suggestion. Default value: _INFINITY_ + +|symmetrical +|If true, which is the default, stop the resources in the reverse + order. Default value: _true_ + +|========================================================= + +=== Mandatory Ordering === + +When the +then+ resource cannot run without the +first+ resource being +active, one should use mandatory constraints. To specify a constraint +is mandatory, use scores greater than zero. This will ensure that the +then resource will react when the first resource changes state. + +* If the +first+ resource was running and is stopped, the +then+ + resource will also be stopped (if it is running). +* If the +first+ resource was not running and cannot be started, the + +then+ resource will be stopped (if it is running). +* If the +first+ resource is (re)started while the +then+ resource is + running, the +then+ resource will be stopped and restarted. + +=== Advisory Ordering === + +On the other hand, when +score="0"+ is specified for a constraint, the +constraint is considered optional and only has an effect when both +resources are stopping and/or starting. Any change in state by the ++first+ resource will have no effect on the +then+ resource. + +.Example of an optional and mandatory ordering constraint +[source,XML] +------- + + + + +------- + +Some additional information on ordering constraints can be found in +the document http://www.clusterlabs.org/mediawiki/images/d/d6/Ordering_Explained.pdf[Ordering Explained]. + +== Placing Resources Relative to other Resources == + +anchor:s-resource-colocation[Resource Colocation] +When the location of one resource depends on the location of another +one, we call this colocation. + +There is an important side-effect of creating a colocation constraint +between two resources: it affects the order in which resources are +assigned to a node. If you think about it, it's somewhat obvious. +You can't place A relative to B unless you know where B is. +footnote:[ +While the human brain is sophisticated enough to read the constraint +in any order and choose the correct one depending on the situation, +the cluster is not quite so smart. Yet. +] + +So when you are creating colocation constraints, it is important to +consider whether you should colocate A with B or B with A. + +Another thing to keep in mind is that, assuming A is collocated with +B, the cluster will also take into account A's preferences when +deciding which node to choose for B. + +For a detailed look at exactly how this occurs, see the +http://www.clusterlabs.org/mediawiki/images/6/61/Colocation_Explained.pdf[Colocation +Explained] document. + +=== Options === + +.Properties of a Collocation Constraint +[width="95%",cols="1m,5<",options="header",align="center"] +|========================================================= + +|Field +|Description + +|id +|A unique name for the constraint. + +|rsc +|The colocation source. If the constraint cannot be satisfied, the + cluster may decide not to allow the resource to run at all. + +|with-rsc +|The colocation target. The cluster will decide where to put this + resource first and then decide where to put the resource in the +rsc+ + field. + +|score +|Positive values indicate the resource should run on the same + node. Negative values indicate the resources should not run on the + same node. Values of \+/- +INFINITY+ change "should" to "must". + +|========================================================= + +=== Mandatory Placement === + +Mandatory placement occurs any time the constraint's score is +++INFINITY+ or +-INFINITY+. In such cases, if the constraint can't be +satisfied, then the +rsc+ resource is not permitted to run. For ++score=INFINITY+, this includes cases where the +with-rsc+ resource is +not active. + +If you need +resource1+ to always run on the same machine as ++resource2+, you would add the following constraint: + +.An example colocation constraint +[source,XML] + + +Remember, because +INFINITY+ was used, if +resource2+ can't run on any +of the cluster nodes (for whatever reason) then +resource1+ will not +be allowed to run. + +Alternatively, you may want the opposite... that +resource1+ cannot +run on the same machine as +resource2+. In this case use ++score="-INFINITY"+ + +.An example anti-colocation constraint +[source,XML] + + +Again, by specifying +-INFINTY+, the constraint is binding. So if the +only place left to run is where +resource2+ already is, then ++resource1+ may not run anywhere. + +=== Advisory Placement === + +If mandatory placement is about "must" and "must not", then advisory +placement is the "I'd prefer if" alternative. For constraints with +scores greater than +-INFINITY+ and less than +INFINITY+, the cluster +will try and accommodate your wishes but may ignore them if the +alternative is to stop some of the cluster resources. + + +Like in life, where if enough people prefer something it effectively +becomes mandatory, advisory colocation constraints can combine with +other elements of the configuration to behave as if they were +mandatory. + +.An example advisory-only colocation constraint +[source,XML] + + +== Ordering Sets of Resources == + +anchor:s-resource-sets-ordering[Resource Sets - Start Ordering] +A common situation is for an administrator to create a chain of +ordered resources, such as: + +.A chain of ordered resources +[source,XML] +------- + + + + + +------- + +== Ordered Set == + +.Visual representation of the four resources' start order for the above constraints +image::images/resource-set.png["Ordered set",width="16cm",height="2.5cm",align="center"] + +To simplify this situation, there is an alternate format for ordering +constraints: + +.A chain of ordered resources expressed as a set +[source,XML] +------- + + + + + + + + + + +------- + +[NOTE] +Resource sets have the same ordering semantics as groups. + +.A group resource with the equivalent ordering rules +[source,XML] +------- + + + + + + +------- + +While the set-based format is not less verbose, it is significantly +easier to get right and maintain. It can also be expanded to allow +ordered sets of (un)ordered resources. In the example below, +rscA+ +and +rscB+ can both start in parallel, as can +rscC+ and +rscD+, +however +rscC+ and +rscD+ can only start once _both_ +rscA+ _and_ + +rscB+ are active. + +.Ordered sets of unordered resources +[source,XML] +------- + + + + + + + + + + + + +------- + +== Two Sets of Unordered Resources == + +.Visual representation of the start order for two ordered sets of unordered resources +image::images/two-sets.png["Two ordered sets",width="13cm",height="7.5cm",align="center"] + + +Of course either set -- or both sets -- of resources can also be +internally ordered (by setting +sequential="true"+) and there is no +limit to the number of sets that can be specified. + +.Advanced use of set ordering - Three ordered sets, two of which are internally unordered +[source,XML] +------- + + + + + + + + + + + + + + + + +------- + +== Three Resources Sets == + +.Visual representation of the start order for the three sets defined above +image::images/three-sets.png["Three ordered sets",width="16cm",height="7.5cm",align="center"] + +== Collocating Sets of Resources == + +anchor:s-resource-sets-collocation[Resource Sets - Colocation] +Another common situation is for an administrator to create a set of +collocated resources. Previously this was possible either by defining +a resource group (See xref:group-resources[]) which could not always +accurately express the design; or by defining each relationship as an +individual constraint, causing a constraint explosion as the number of +resources and combinations grew. + +.A chain of collocated resources +[source,XML] +------- + + + + + +------- + +To make things easier, we allow an alternate form of colocation +constraints using +resource_sets+. Just like the expanded version, a +resource that can't be active also prevents any resource that must be +collocated with it from being active. For example, if +B was+ not +able to run, then both +C (+and by inference +D)+ must also remain +stopped. + +.The equivalent colocation chain expressed using +resource_sets+ +[source,XML] +------- + + + + + + + + + + +------- + +[NOTE] +Resource sets have the same colocation semantics as groups. + +.A group resource with the equivalent colocation rules +[source,XML] +------- + + + + + + +------- + +This notation can also be used in this context to tell the cluster +that a set of resources must all be located with a common peer, but +have no dependencies on each other. In this scenario, unlike the +previous, +B would+ be allowed to remain active even if +A or+ +C+ (or +both) were inactive. + +.Using colocation sets to specify a common peer. +[source,XML] +------- + + + + + + + + + + + + +------- + +Of course there is no limit to the number and size of the sets used. +The only thing that matters is that in order for any member of set N +to be active, all the members of set N+1 must also be active (and +naturally on the same node); and if a set has +sequential="true"+, +then in order for member M to be active, member M+1 must also be +active. You can even specify the role in which the members of a set +must be in using the set's role attribute. + +.A colocation chain where the members of the middle set have no inter-dependencies and the last has master status. +[source,XML] +------- + + + + + + + + + + + + + + + + + +------- + +== Another Three Resources Sets == + +.Visual representation of a colocation chain where the members of the middle set have no inter-dependencies +image::images/three-sets-complex.png["Colocation chain",width="16cm",height="9cm",align="center"] diff --git a/doc/Pacemaker_Explained/en-US/Ch-Constraints.xml b/doc/Pacemaker_Explained/en-US/Ch-Constraints.xml deleted file mode 100644 index 49c51e501f..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ch-Constraints.xml +++ /dev/null @@ -1,510 +0,0 @@ - Resource Constraints -
- Scores - ResourceConstraints - Constraintsfor Resources - - Scores of all kinds are integral to how the cluster works. - Practically everything from moving a resource to deciding which resource to stop in a degraded cluster is achieved by manipulating scores in some way. - - - Scores are calculated on a per-resource basis and any node with a negative score for a resource can't run that resource. - After calculating the scores for a resource, the cluster then chooses the node with the highest one. - -
- Infinity Math - INFINITY is currently defined as 1,000,000 and addition/subtraction with it follows these three basic rules: - - Any value + INFINITY = INFINITY - Any value - INFINITY = -INFINITY - INFINITY - INFINITY = -INFINITY - -
-
-
- Deciding Which Nodes a Resource Can Run On - - There are two alternative strategies for specifying which nodes a resources can run on. - One way is to say that by default they can run anywhere and then create location constraints for nodes that are not allowed. - The other option is to have nodes "opt-in"... - to start with nothing able to run anywhere and selectively enable allowed nodes. - -
- Options - - Options for Simple Location Constraints - - - - - - Field - Description - - - - - idConstraint Field - Constraint Fieldid - id - A unique name for the constraint - - - rsc Constraint Field - Constraint Fieldrsc - rsc - A resource name - - - NodeConstraint Field - Constraint Fieldnode - node - A node's uname - - - scoreConstraint Field - Constraint Fieldscore - score - Positive values indicate the resource should run on this node. Negative values indicate the resource should not run on this node. Values of +/- INFINITY change "should"/"should not" to "must"/"must not". - - - -
-
-
- <indexterm significance="preferred"><primary>Asymmetrical Opt-In Clusters</primary></indexterm> - <indexterm significance="preferred"><primary>Cluster Type</primary><secondary>Asymmetrical Opt-In</secondary></indexterm> - Asymmetrical "Opt-In" Clusters - To create an opt-in cluster, start by preventing resources from running anywhere by default: - crm_attribute --attr-name symmetric-cluster --attr-value false - - Then start enabling nodes. - The following fragment says that the web server prefers sles-1, the database prefers sles-2 and both can fail over to sles-3 if their most preferred node fails. - - - Example set of opt-in location constraints - - - - - - ]]> - -
-
- <indexterm significance="preferred"><primary>Symmetrical Opt-Out Clusters</primary></indexterm> - <indexterm significance="preferred"><primary>Cluster Type</primary><secondary>Symmetrical Opt-Out</secondary></indexterm> - Symmetrical "Opt-Out" Clusters - To create an opt-out cluster, start by allowing resources to run anywhere by default - crm_attribute --attr-name symmetric-cluster --attr-value true - - Then start disabling nodes. - The following fragment is the equivalent of the above opt-in configuration. - - - Example set of opt-out location constraints - - - - - - ]]> - - - Whether you should choose opt-in or opt-out depends both on your personal preference and the make-up of your cluster. - If most of your resources can run on most of the nodes, then an opt-out arrangement is likely to result in a simpler configuration. - On the other-hand, if most resources can only run on a small subset of nodes an opt-in configuration might be simpler. - -
-
- What if Two Nodes Have the Same Score - - If two nodes have the same score, then the cluster will choose one. - This choice may seem random and may not be what was intended, however the cluster was not given enough information to know any better. - - - Example of two resources that prefer two nodes equally - - - - - - - ]]> - - - In the example above, assuming no other constraints and an inactive cluster, Webserver would probably be placed on sles-1 and Database on sles-2. - It would likely have placed Webserver based on the node's uname and Database based on the desire to spread the resource load evenly across the cluster. - However other factors can also be involved in more complex configurations. - -
-
-
- Specifying in which Order Resources Should Start/Stop - The way to specify the order in which resources should start is by creating rsc_order constraints. - - Properties of an Ordering Constraint - - - - - - Field - Description - - - - - id - A unique name for the constraint - - - first - The name of a resource that must be started before the then resource is allowed to. - - - then - The name of a resource. This resource will start after the first resource. - - - score - If greater than zero, the constraint is mandatory. Otherwise it is only a suggestion. Default value: INFINITY - - - - symmetrical - If true, which is the default, stop the resources in the reverse order. Default value: true - - - -
-
- Mandatory Ordering - - When the then resource cannot run without the first resource being active, one should use mandatory constraints. - To specify a constraint is mandatory, use scores greater than zero. - This will ensure that the then resource will react when the first resource changes state. - - - If the first resource was running and is stopped, the then resource will also be stopped (if it is running). - If the first resource was not running and cannot be started, the then resource will be stopped (if it is running). - If the first resource is (re)started while the then resource is running, the then resource will be stopped and restarted. - -
-
- Advisory Ordering - - On the other hand, when score="0" is specified for a constraint, the constraint is considered optional and only has an effect when both resources are stopping and/or starting. - Any change in state by the first resource will have no effect on the then resource. - - - Example of an optional and mandatory ordering constraint - - - - ]]> - - Some additional information on ordering constraints can be found in the document Ordering Explained. - -
-
-
- Placing Resources Relative to other Resources - When the location of one resource depends on the location of another one, we call this colocation. - - There is an important side-effect of creating a colocation constraint between two resources: it affects the order in which resources are assigned to a node. - If you think about it, it's somewhat obvious. - You can't place A relative to B unless you know where B is - While the human brain is sophisticated enough to read the constraint in any order and choose the correct one depending on the situation, the cluster is not quite so smart. Yet. - . - So when you are creating colocation constraints, it is important to consider whether you should colocate A with B or B with A. - - - Another thing to keep in mind is that, assuming A is collocated with B, the cluster will also take into account A's preferences when deciding which node to choose for B. - For a detailed look at exactly how this occurs, see the Colocation Explained document. - -
- Options - - Properties of a Collocation Constraint - - - - - - Field - Description - - - - - id - A unique name for the constraint. - - - rsc - The colocation source. If the constraint cannot be satisfied, the cluster may decide not to allow the resource to run at all. - - - with-rsc - The colocation target. The cluster will decide where to put this resource first and then decide where to put the resource in the rsc field. - - - score - Positive values indicate the resource should run on the same node. Negative values indicate the resources should not run on the same node. Values of +/- INFINITY change "should" to "must". - - - -
-
-
- Mandatory Placement - - Mandatory placement occurs any time the constraint's score is +INFINITY or -INFINITY. - In such cases, if the constraint can't be satisfied, then the rsc resource is not permitted to run. - For score=INFINITY, this includes cases where the with-rsc resource is not active. - - If you need resource1 to always run on the same machine as resource2, you would add the following constraint: - - An example colocation constraint - <rsc_colocation id="colocate" rsc="resource1" with-rsc="resource2" score="INFINITY"/> - - - Remember, because INFINITY was used, if resource2 can't run on any of the cluster nodes (for whatever reason) then resource1 will not be allowed to run. - - Alternatively, you may want the opposite... - that resource1 cannot run on the same machine as resource2. - In this case use score="-INFINITY" - - - An example anti-colocation constraint - <rsc_colocation id="anti-colocate" - rsc="resource1" with-rsc="resource2" score="-INFINITY"/> - - - - Again, by specifying -INFINTY, the constraint is binding. - So if the only place left to run is where resource2 already is, then resource1 may not run anywhere. - -
-
- Advisory Placement - - If mandatory placement is about "must" and "must not", then advisory placement is the "I'd prefer if" alternative. - For constraints with scores greater than -INFINITY and less than INFINITY, the cluster will try and accommodate your wishes but may ignore them if the alternative is to stop some of the cluster resources. - - Like in life, where if enough people prefer something it effectively becomes mandatory, advisory colocation constraints can combine with other elements of the configuration to behave as if they were mandatory. - - An example advisory-only colocation constraint - <rsc_colocation id="colocate-maybe" rsc="resource1" with-rsc="resource2" score="500"/> - - -
-
-
- Ordering Sets of Resources - A common situation is for an administrator to create a chain of ordered resources, such as: - - A chain of ordered resources - - - - - ]]> - - -
- Ordered Set - - - - - Visual representation of the four resources' start order for the above constraints - -
- - To simplify this situation, there is an alternate format for ordering constraints: - - A chain of ordered resources expressed as a set - - - - - - - - - - ]]> - - Resource sets have the same ordering semantics as groups. - - A group resource with the equivalent ordering rules - - - - - - ]]> - - - While the set-based format is not less verbose, it is significantly easier to get right and maintain. - It can also be expanded to allow ordered sets of (un)ordered resources. - In the example below, rscA and rscB can both start in parallel, as can rscC and rscD, however rscC and rscD can only start once both rscA and rscB are active. - - Ordered sets of unordered resources - - - - - - - - - - - - ]]> - - -
- Two Sets of Unordered Resources - - - - - Visual representation of the start order for two ordered sets of unordered resources - -
- - Of course either set -- or both sets -- of resources can also be internally ordered (by setting sequential="true") and there is no limit to the number of sets that can be specified. - - Advanced use of set ordering - Three ordered sets, two of which are internally unordered - - - - - - - - - - - - - - - - ]]> - - -
- Three Resources Sets - - - - - Visual representation of the start order for the three sets defined above - -
- -
-
- Collocating Sets of Resources - - Another common situation is for an administrator to create a set of collocated resources. - Previously this was possible either by defining a resource group (See ) which could not always accurately express the design; or by defining each relationship as an individual constraint, causing a constraint explosion as the number of resources and combinations grew. - - - A chain of collocated resources - - - - - ]]> - - - To make things easier, we allow an alternate form of colocation constraints using resource_sets. - Just like the expanded version, a resource that can't be active also prevents any resource that must be collocated with it from being active. - For example, if B was not able to run, then both C (and by inference D) must also remain stopped. - - - The equivalent colocation chain expressed using <literal>resource_sets</literal> - - - - - - - - - - ]]> - - Resource sets have the same colocation semantics as groups. - - A group resource with the equivalent colocation rules - - - - - - ]]> - - - This notation can also be used in this context to tell the cluster that a set of resources must all be located with a common peer, but have no dependencies on each other. - In this scenario, unlike the previous, B would be allowed to remain active even if A or C (or both) were inactive. - - - Using colocation sets to specify a common peer. - - - - - - - - - - - - ]]> - - - Of course there is no limit to the number and size of the sets used. - The only thing that matters is that in order for any member of set N to be active, all the members of set N+1 must also be active (and naturally on the same node); and if a set has sequential="true", then in order for member M to be active, member M+1 must also be active. - You can even specify the role in which the members of a set must be in using the set's role attribute. - - - A colocation chain where the members of the middle set have no inter-dependencies and the last has master status. - - - - - - - - - - - - - - - - - ]]> - - -
- Another Three Resources Sets - - - - - Visual representation of a colocation chain where the members of the middle set have no inter-dependencies - -
- -
- diff --git a/doc/Pacemaker_Explained/en-US/Ch-Intro.txt b/doc/Pacemaker_Explained/en-US/Ch-Intro.txt new file mode 100644 index 0000000000..20a563be1f --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ch-Intro.txt @@ -0,0 +1,175 @@ += Read-Me-First = + +== The Scope of this Document == + +The purpose of this document is to definitively explain the concepts +used to configure Pacemaker. To achieve this, it will focus +exclusively on the XML syntax used to configure the CIB. + +For those that are allergic to XML, there exist several unified shells +and GUIs for Pacemaker. However these tools will not be covered at all +in this document +footnote:[I hope, however, that the concepts explained here make the functionality of these tools more easily understood.] +, precisely because they hide the XML. + +Additionally, this document is NOT a step-by-step how-to guide for +configuring a specific clustering scenario. + +Although such guides exist, the purpose of this document is to provide +an understanding of the building blocks that can be used to construct +any type of Pacemaker cluster. + +== What Is Pacemaker? == + +Pacemaker is a cluster resource manager. + +It achieves maximum availability for your cluster services +(aka. resources) by detecting and recovering from node and +resource-level failures by making use of the messaging and membership +capabilities provided by your preferred cluster infrastructure (either +http://www.corosync.org/[Corosync] or +http://linux-ha.org/wiki/Heartbeat[Heartbeat]. + +Pacemaker's key features include: + +* Detection and recovery of node and service-level failures +* Storage agnostic, no requirement for shared storage +* Resource agnostic, anything that can be scripted can be clustered +* Supports http://en.wikipedia.org/wiki/STONITH[STONITH] for ensuring data integrity +* Supports large and small clusters +* Supports both http://en.wikipedia.org/wiki/Quorum_(Distributed_Systems)[quorate] and http://devresources.linux-foundation.org/dev/clusters/docs/ResourceDrivenClusters.pdf[resource driven] clusters +* Supports practically any http://en.wikipedia.org/wiki/High-availability_cluster#Node_configurations[redundancy configuration] +* Automatically replicated configuration that can be updated from any node +* Ability to specify cluster-wide service ordering, colocation and anti-colocation +* Support for advanced services type +** Clones: for services which need to be active on multiple nodes +** Multi-state: for services with multiple modes (eg. master/slave, primary/secondary) + +== Types of Pacemaker Clusters == + +Pacemaker makes no assumptions about your environment, this allows it +to support practically any +http://en.wikipedia.org/wiki/High-availability_cluster#Node_configurations[redundancy configuration] +including Active/Active, Active/Passive, N+1, N+M, N-to-1 and N-to-N. + +.Active/Passive Redundancy +image::images/pcmk-active-passive.png["Active/Passive Redundancy",width="10cm",height="7.5cm",align="center"] + +Two-node Active/Passive clusters using Pacemaker and DRBD are a +cost-effective solution for many High Availability situations. + +.Shared Failover +image::images/pcmk-shared-failover.png["Shared Failover",width="10cm",height="7.5cm",align="center"] + +By supporting many nodes, Pacemaker can dramatically reduce hardware +costs by allowing several active/passive clusters to be combined and +share a common backup node + +.N to N Redundancy +image::images/pcmk-active-active.png["N to N Redundancy",width="10cm",height="7.5cm",align="center"] + +When shared storage is available, every node can potentially be used +for failover. Pacemaker can even run multiple copies of services to +spread out the workload. + + +== Pacemaker Architecture == + +At the highest level, the cluster is made up of three pieces: + +* Core cluster infrastructure providing messaging and membership + functionality (illustrated in red) +* Non-cluster aware components (illustrated in green). ++ +In a Pacemaker cluster, these pieces include not only the scripts +that knows how to start, stop and monitor resources, but also a local +daemon that masks the differences between the different standards +these scripts implement. ++ +* A brain (illustrated in blue) ++ +This component processes and reacts to events from the cluster (nodes +leaving or joining) and resources (eg. monitor failures) as well as +configuration changes from the administrator. In response to all of +these events, Pacemaker will compute the ideal state of the cluster +and plot a path to achieve it. This may include moving resources, +stopping nodes and even forcing nodes offline with remote power +switches. ++ + +//// +Hack to force end list +//// + + +=== Conceptual Stack Overview === + +.Conceptual overview of the cluster stack +image::images/pcmk-overview.png["Conceptual overview of the cluster stack",width="10cm",height="7.5cm",align="center"] + +When combined with Corosync, Pacemaker also supports popular open +source cluster filesystems. +footnote:[ +Even though Pacemaker also supports Heartbeat, the filesystems need to +use the stack for messaging and membership and Corosync seems to be +what they're standardizing on. + +Technically it would be possible for them to support Heartbeat as +well, however there seems little interest in this. +] + +Due to recent standardization within the cluster filesystem community, +they make use of a common distributed lock manager which makes use of +Corosync for its messaging capabilities and Pacemaker for its +membership (which nodes are up/down) and fencing services. + +.The Pacemaker stack when running on Corosync +image::images/pcmk-stack.png["The Pacemaker stack when running on Corosync",width="10cm",height="7.5cm",align="center"] + +=== Internal Components === + +Pacemaker itself is composed of four key components (illustrated below +in the same color scheme as the previous diagram): + +* CIB (aka. Cluster Information Base) +* CRMd (aka. Cluster Resource Management daemon) +* PEngine (aka. PE or Policy Engine) +* STONITHd + +.Subsystems of a Pacemaker cluster +image::images/pcmk-internals.png["Subsystems of a Pacemaker cluster",width="10cm",height="7.5cm",align="center"] + +The CIB uses XML to represent both the cluster's configuration and +current state of all resources in the cluster. The contents of the +CIB are automatically kept in sync across the entire cluster and are +used by the PEngine to compute the ideal state of the cluster and how +it should be achieved. + +This list of instructions is then fed to the DC (Designated +Controller). Pacemaker centralizes all cluster decision making by +electing one of the CRMd instances to act as a master. Should the +elected CRMd process (or the node it is on) fail... a new one is +quickly established. + +The DC carries out PEngine's instructions in the required order by +passing them to either the LRMd (Local Resource Management daemon) or +CRMd peers on other nodes via the cluster messaging infrastructure +(which in turn passes them on to their LRMd process). + +The peer nodes all report the results of their operations back to the +DC and, based on the expected and actual results, will either execute +any actions that needed to wait for the previous one to complete, or +abort processing and ask the PEngine to recalculate the ideal cluster +state based on the unexpected results. + +In some cases, it may be necessary to power off nodes in order to +protect shared data or complete resource recovery. For this Pacemaker +comes with STONITHd. + +STONITH is an acronym for Shoot-The-Other-Node-In-The-Head and is +usually implemented with a remote power switch. + +In Pacemaker, STONITH devices are modeled as resources (and configured +in the CIB) to enable them to be easily monitored for failure, however +STONITHd takes care of understanding the STONITH topology such that +its clients simply request a node be fenced and it does the rest. diff --git a/doc/Pacemaker_Explained/en-US/Ch-Intro.xml b/doc/Pacemaker_Explained/en-US/Ch-Intro.xml deleted file mode 100644 index 992a771e80..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ch-Intro.xml +++ /dev/null @@ -1,172 +0,0 @@ - Read-Me-First -
- The Scope of this Document - - The purpose of this document is to definitively explain the concepts used to configure Pacemaker. - To achieve this, it will focus exclusively on the XML syntax used to configure the CIB. - - - For those that are allergic to XML, Pacemaker comes with a cluster shell; a Python based GUI exists, too, however these tools will not be covered at all in this document - I hope, however, that the concepts explained here make the functionality of these tools more easily understood. - , precisely because they hide the XML. - - - Additionally, this document is NOT a step-by-step how-to guide for configuring a specific clustering scenario. - Although such guides exist, the purpose of this document is to provide an understanding of the building blocks that can be used to construct any type of Pacemaker cluster. - -
-
- What Is Pacemaker? - - Pacemaker is a cluster resource manager. - It achieves maximum availability for your cluster services (aka. resources) by detecting and recovering from node and resource-level failures by making use of the messaging and membership capabilities provided by your preferred cluster infrastructure (either Corosync or Heartbeat). - - Pacemaker's key features include: - - Detection and recovery of node and service-level failures - Storage agnostic, no requirement for shared storage - Resource agnostic, anything that can be scripted can be clustered - Supports STONITH for ensuring data integrity - Supports large and small clusters - Supports both quorate and resource driven clusters TODO: quorum-driven? - Supports practically any redundancy configuration - Automatically replicated configuration that can be updated from any node - Ability to specify cluster-wide service ordering, colocation and anti-colocation - Support for advanced services type - - Clones: for services which need to be active on multiple nodes - Multi-state: for services with multiple modes (eg. master/slave, primary/secondary) - - - Unified, scriptable, cluster shell - -
-
- Types of Pacemaker Clusters - Pacemaker makes no assumptions about your environment, this allows it to support practically any redundancy configuration including Active/Active, Active/Passive, N+1, N+M, N-to-1 and N-to-N. - - -
- Active/Passive Redundancy - - - - - Two-node Active/Passive clusters using Pacemaker and DRBD are a cost-effective solution for many High Availability situations. - -
- - -
- Shared Failover - - - - - By supporting many nodes, Pacemaker can dramatically reduce hardware costs by allowing several active/passive clusters to be combined and share a common backup node - -
- - -
- N to N Redundancy - - - - - - When shared storage is available, every node can potentially be used for failover. - Pacemaker can even run multiple copies of services to spread out the workload. - - -
- -
-
- Pacemaker Architecture - At the highest level, the cluster is made up of three pieces: - - - Core cluster infrastructure providing messaging and membership functionality (illustrated in red) - - - Non-cluster aware components (illustrated in green). - In a Pacemaker cluster, these pieces include not only the scripts that knows how to start, stop and monitor resources, but also a local daemon that masks the differences between the different standards these scripts implement. - - - A brain (illustrated in blue) that processes and reacts to events from the cluster (nodes leaving or joining) and resources (eg. monitor failures) as well as configuration changes from the administrator. - In response to all of these events, Pacemaker will compute the ideal state of the cluster and plot a path to achieve it. - This may include moving resources, stopping nodes and even forcing nodes offline with remote power switches. - - - -
- Conceptual Stack Overview - - - - - Conceptual overview of the cluster stack - -
- - When combined with Corosync, Pacemaker also supports popular open source cluster filesystems - - Even though Pacemaker also supports Heartbeat, the filesystems need to use the stack for messaging and membership and Corosync seems to be what they're standardizing on. - Technically it would be possible for them to support Heartbeat as well, however there seems little interest in this. - - . - Due to recent standardization within the cluster filesystem community, they make use of a common distributed lock manager which makes use of Corosync for its messaging capabilities and Pacemaker for its membership (which nodes are up/down) and fencing services. - - -
- The Pacemaker Stack - - - - - The Pacemaker stack when running on Corosync - -
- -
- Internal Components - Pacemaker itself is composed of four key components (illustrated below in the same color scheme as the previous diagram): - - CIB (aka. Cluster Information Base) - CRMd (aka. Cluster Resource Management daemon) - PEngine (aka. PE or Policy Engine) - STONITHd - - -
- Internal Components - - - - - Subsystems of a Pacemaker cluster - -
- - - The CIB uses XML to represent both the cluster's configuration and current state of all resources in the cluster. - The contents of the CIB are automatically kept in sync across the entire cluster and are used by the PEngine to compute the ideal state of the cluster and how it should be achieved. - - - This list of instructions is then fed to the DC (Designated Controller). - Pacemaker centralizes all cluster decision making by electing one of the CRMd instances to act as a master. - Should the elected CRMd process (or the node it is on) fail... - a new one is quickly established. - - The DC carries out PEngine's instructions in the required order by passing them to either the LRMd (Local Resource Management daemon) or CRMd peers on other nodes via the cluster messaging infrastructure (which in turn passes them on to their LRMd process). - The peer nodes all report the results of their operations back to the DC and, based on the expected and actual results, will either execute any actions that needed to wait for the previous one to complete, or abort processing and ask the PEngine to recalculate the ideal cluster state based on the unexpected results. - - In some cases, it may be necessary to power off nodes in order to protect shared data or complete resource recovery. - For this Pacemaker comes with STONITHd. - STONITH is an acronym for Shoot-The-Other-Node-In-The-Head and is usually implemented with a remote power switch. - In Pacemaker, STONITH devices are modeled as resources (and configured in the CIB) to enable them to be easily monitored for failure, however STONITHd takes care of understanding the STONITH topology such that its clients simply request a node be fenced and it does the rest. - -
-
- diff --git a/doc/Pacemaker_Explained/en-US/Ch-Nodes.txt b/doc/Pacemaker_Explained/en-US/Ch-Nodes.txt new file mode 100644 index 0000000000..a4e34e3067 --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ch-Nodes.txt @@ -0,0 +1,157 @@ += Cluster Nodes = + +== Defining a Cluster Node == + +Each node in the cluster will have an entry in the nodes section +containing its UUID, uname, and type. + +.Example cluster node entry +[source,XML] +------- + +------- + +In normal circumstances, the admin should let the cluster populate +this information automatically from the communications and membership +data. However one can use the `crm_uuid` tool +to read an existing UUID or define a value before the cluster starts. + +== Describing a Cluster Node == + +anchor:s-node-attributes[Describing a Cluster Node] +Beyond the basic definition of a node the administrator can also +describe the node's attributes, such as how much RAM, disk, what OS or +kernel version it has, perhaps even its physical location. This +information can then be used by the cluster when deciding where to +place resources. For more information on the use of node attributes, +see the section on xref:ch-rules[]. + +Node attributes can be specified ahead of time or populated later, +when the cluster is running, using `crm_attribute`. + +Below is what the node's definition would look like if the admin ran the command: + +.The result of using crm_attribute to specify which kernel pcmk-1 is running +[source,XML] +------- +# crm_attribute --type nodes --node-uname pcmk-1 --attr-name kernel --attr-value `uname -r` + + + + + + +------- + +A simpler way to determine the current value of an attribute is to use `crm_attribute` command again: + + ` crm_attribute --type nodes --node-uname pcmk-1 --attr-name kernel --get-value` + +By specifying --type nodes the admin tells the +cluster that this attribute is persistent. There are also transient +attributes which are kept in the status section which are "forgotten" +whenever the node rejoins the cluster. The cluster uses this area to +store a record of how many times a resource has failed on that node +but administrators can also read and write to this section by +specifying --type status. + +== Adding a New Cluster Node == + +=== Corosync === + +Adding a new node is as simple as installing Corosync and Pacemaker, +and copying _/etc/corosync/corosync.conf_ and _/etc/ais/authkey_ (if +it exists) from an existing node. You may need to modify the ++mcastaddr+ option to match the new node's IP address. + +If a log message containing "Invalid digest" appears from Corosync, +the keys are not consistent between the machines. + +=== Heartbeat === + +Provided you specified +autojoin any+ in _ha.cf_, adding a new node is +as simple as installing heartbeat and copying _ha.cf_ and _authkeys_ +from an existing node. + +If you don't want to use +autojoin+, then after setting up _ha.cf_ and +_authkeys_, you must use the `hb_addnode` +command before starting the new node. + + +== Removing a Cluster Node == + +=== Corosync === + +Because the messaging and membership layers are the authoritative +source for cluster nodes, deleting them from the CIB is not a reliable +solution. First one must arrange for heartbeat to forget about the +node (_pcmk-1_ in the example below). + +On the host to be removed: + +. Find and record the node's Corosync id: `crm_node -i` +. Stop the cluster: `/etc/init.d/corosync stop` + +Next, from one of the remaining active cluster nodes: + +. Tell the cluster to forget about the removed host: ++ +[source,Bash] +crm_node -R $COROSYNC_ID ++ +. Only now is it safe to delete the node from the CIB with: ++ +[source,Bash] +----- +cibadmin --delete --obj_type nodes --crm_xml '' +cibadmin --delete --obj_type status --crm_xml '' +----- + + +=== Heartbeat === + +Because the messaging and membership layers are the authoritative +source for cluster nodes, deleting them from the CIB is not a reliable +solution. + +First one must arrange for heartbeat to forget about the node (pcmk-1 +in the example below). To do this, shut down heartbeat on the node +and then, from one of the remaining active cluster nodes, run: + +[source,Bash] +hb_delnode pcmk-1 + +Only then is it safe to delete the node from the CIB with: + +[source,Bash] +----- +cibadmin --delete --obj_type nodes --crm_xml '' +cibadmin --delete --obj_type status --crm_xml '' +----- + +== Replacing a Cluster Node == + +=== Corosync === + +The five-step guide to replacing an existing cluster node: + +. Make sure the old node is completely stopped +. Give the new machine the same hostname and IP address as the old one +. Install the cluster software :-) +. Copy _/etc/corosync/corosync.conf_ and _/etc/ais/authkey_ (if it exists) to the new node +. Start the new cluster node + +If a log message containing "Invalid digest" appears from Corosync, +the keys are not consistent between the machines. + +=== Heartbeat === + +The seven-step guide to replacing an existing cluster node: + +. Make sure the old node is completely stopped +. Give the new machine the same hostname as the old one +. Go to an active cluster node and look up the UUID for the old node in _/var/lib/heartbeat/hostcache_ +. Install the cluster software +. Copy _ha.cf_ and _authkeys_ to the new node +. On the new node, populate it's UUID using `crm_uuid -w` and the UUID from step 2 +. Start the new cluster node diff --git a/doc/Pacemaker_Explained/en-US/Ch-Nodes.xml b/doc/Pacemaker_Explained/en-US/Ch-Nodes.xml deleted file mode 100644 index 80b8bff2c0..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ch-Nodes.xml +++ /dev/null @@ -1,128 +0,0 @@ - - Cluster Nodes -
- Defining a Cluster Node - Each node in the cluster will have an entry in the nodes section containing its UUID, uname, and type. - - Example cluster node entry - ]]> - - - - In normal circumstances, the admin should let the cluster populate this information automatically from the communications and membership data. - However one can use the crm_uuid tool to read an existing UUID or define a value before the cluster starts. - -
-
- Describing a Cluster Node - - Beyond the basic definition of a node the administrator can also describe the node's attributes, such as how much RAM, disk, what OS or kernel version it has, perhaps even its physical location. - This information can then be used by the cluster when deciding where to place resources. - For more information on the use of node attributes, see the section on . - - Node attributes can be specified ahead of time or populated later, when the cluster is running, using crm_attribute. - Below is what the node's definition would look like if the admin ran the command: -
- The result of using crm_attribute to specify which kernel pcmk-1 is running - crm_attribute --type nodes --node-uname pcmk-1 --attr-name kernel --attr-value `uname -r` - - - - - ]]> -
- A simpler way to determine the current value of an attribute is to use crm_attribute command again: - crm_attribute --type nodes --node-uname pcmk-1 --attr-name kernel --get-value - - - By specifying --type nodes the admin tells the cluster that this attribute is persistent. - There are also transient attributes which are kept in the status section which are "forgotten" whenever the node rejoins the cluster. - The cluster uses this area to store a record of how many times a resource has failed on that node but administrators can also read and write to this section by specifying --type status. - -
-
- Adding a New Cluster Node -
- Corosync - Adding a new node is as simple as installing Corosync and Pacemaker, and copying /etc/corosync/corosync.conf and /etc/ais/authkey (if it exists) from an existing node. -You may need to modify the mcastaddr option to match the new node's IP address. - If a log message containing "Invalid digest" appears from Corosync, the keys are not consistent between the machines. -
-
- Heartbeat - Provided you specified autojoin any in ha.cf, adding a new node is as simple as installing heartbeat and copying ha.cf and authkeys from an existing node. - If you don't want to use autojoin, then after setting up ha.cf and authkeys, you must use the hb_addnode command before starting the new node. -
-
-
- Removing a Cluster Node -
- Corosync - - Because the messaging and membership layers are the authoritative source for cluster nodes, deleting them from the CIB is not a reliable solution. - First one must arrange for heartbeat to forget about the node (pcmk-1 in the example below). - - On the host to be removed: - - - Find and record the node's Corosync id: crm_node -i - - - Stop the cluster: /etc/init.d/corosync stop - - - Next, from one of the remaining active cluster nodes: - - - Tell the cluster to forget about the removed host: crm_node -R COROSYNC_ID - - - Only now is it safe to delete the node from the CIB with: - cibadmin --delete --obj_type nodes --crm_xml '<node uname="pcmk-1"/>' - cibadmin --delete --obj_type status --crm_xml '<node_state uname="pcmk-1"/>' - - -
-
- Heartbeat - - Because the messaging and membership layers are the authoritative source for cluster nodes, deleting them from the CIB is not a reliable solution. - First one must arrange for heartbeat to forget about the node (pcmk-1 in the example below). - To do this, shut down heartbeat on the node and then, from one of the remaining active cluster nodes, run: - - hb_delnode pcmk-1 - Only then is it safe to delete the node from the CIB with: - cibadmin --delete --obj_type nodes --crm_xml '<node uname="pcmk-1"/>' - cibadmin --delete --obj_type status --crm_xml '<node_state uname="pcmk-1"/>' -
-
-
- Replacing a Cluster Node -
- Corosync - The five-step guide to replacing an existing cluster node: - - Make sure the old node is completely stopped - Give the new machine the same hostname and IP address as the old one - Install the cluster software :-) - Copy /etc/corosync/corosync.conf and /etc/ais/authkey (if it exists) to the new node - Start the new cluster node - - If a log message containing "Invalid digest" appears from Corosync, the keys are not consistent between the machines. -
-
- Heartbeat - The seven-step guide to replacing an existing cluster node: - - Make sure the old node is completely stopped - Give the new machine the same hostname as the old one - Go to an active cluster node and look up the UUID for the old node in /var/lib/heartbeat/hostcache - Install the cluster software - Copy ha.cf and authkeys to the new node - On the new node, populate it's UUID using crm_uuid -w and the UUID from step 2 - Start the new cluster node - -
-
- diff --git a/doc/Pacemaker_Explained/en-US/Ch-Options.txt b/doc/Pacemaker_Explained/en-US/Ch-Options.txt index 71c58884dd..180f4c906e 100644 --- a/doc/Pacemaker_Explained/en-US/Ch-Options.txt +++ b/doc/Pacemaker_Explained/en-US/Ch-Options.txt @@ -1,278 +1,278 @@ = Cluster Options = == Special Options == indexterm:[Special Cluster Options] indexterm:[Cluster Options,Special Options] The reason for these fields to be placed at the top level instead of with the rest of cluster options is simply a matter of parsing. These options are used by the configuration database which is, by design, mostly ignorant of the content it holds. So the decision was made to place them in an easy to find location. == Configuration Version == indexterm:[Configuration Version, Cluster Option] indexterm:[Cluster Options,Configuration Version] When a node joins the cluster, the cluster will perform a check to see who has the best configuration based on the fields below. It then asks the node with the highest (+admin_epoch+, +epoch+, +num_updates+) tuple to replace the configuration on all the nodes - which makes setting them, and setting them correctly, very important. .Configuration Version Properties [width="95%",cols="1m,5<",options="header",align="center"] |========================================================= |Field |Description | admin_epoch | indexterm:[admin_epoch Cluster Option] indexterm:[Cluster Options,admin_epoch] Never modified by the cluster. Use this to make the configurations on any inactive nodes obsolete. _Never set this value to zero_, in such cases the cluster cannot tell the difference between your configuration and the "empty" one used when nothing is found on disk. | epoch | indexterm:[epoch Cluster Option] indexterm:[Cluster Options,epoch] Incremented every time the configuration is updated (usually by the admin) | num_updates | indexterm:[num_updates Cluster Option] indexterm:[Cluster Options,num_updates] Incremented every time the configuration or status is updated (usually by the cluster) |========================================================= == Other Fields == .Properties Controlling Validation [width="95%",cols="1m,5<",options="header",align="center"] |========================================================= |Field |Description | validate-with | indexterm:[validate-with Cluster Option] indexterm:[Cluster Options,validate-with] Determines the type of validation being done on the configuration. If set to "none", the cluster will not verify that updates conform to the DTD (nor reject ones that don't). This option can be useful when operating a mixed version cluster during an upgrade. |========================================================= == Fields Maintained by the Cluster == .Properties Maintained by the Cluster [width="95%",cols="1m,5<",options="header",align="center"] |========================================================= |Field |Description |cib-last-written | indexterm:[cib-last-written Cluster Fields] indexterm:[Cluster Fields,cib-last-written] Indicates when the configuration was last written to disk. Informational purposes only. |dc-uuid | indexterm:[dc-uuid Cluster Fields] indexterm:[Cluster Fields,dc-uuid] Indicates which cluster node is the current leader. Used by the cluster when placing resources and determining the order of some events. |have-quorum | indexterm:[have-quorum Cluster Fields] indexterm:[Cluster Fields,have-quorum] Indicates if the cluster has quorum. If false, this may mean that the cluster cannot start resources or fence other nodes. See +no-quorum-policy+ below. |========================================================= Note that although these fields can be written to by the admin, in most cases the cluster will overwrite any values specified by the admin with the "correct" ones. To change the +admin_epoch+, for example, one would use: -pass:[cibadmin --modify --crm_xml ‘<cib admin_epoch="42"/>'] +`cibadmin --modify --crm_xml ‘<cib admin_epoch="42"/>'` A complete set of fields will look something like this: .An example of the fields set for a cib object [source,XML] ------- ------- == Cluster Options == Cluster options, as you might expect, control how the cluster behaves when confronted with certain situations. They are grouped into sets and, in advanced configurations, there may be more than one. footnote:[This will be described later in the section on <> where we will show how to have the cluster use different sets of options during working hours (when downtime is usually to be avoided at all costs) than it does during the weekends (when resources can be moved to the their preferred hosts without bothering end users)] For now we will describe the simple case where each option is present at most once. == Available Cluster Options == .Cluster Options [width="95%",cols="5m,2m,13",options="header",align="center"] |========================================================= |Option |Default |Description | batch-limit | 30 | indexterm:[batch-limit Cluster Options] indexterm:[Cluster Options,batch-limit] The number of jobs that the TE is allowed to execute in parallel. The "correct" value will depend on the speed and load of your network and cluster nodes. | migration-limit | -1 (unlimited) | indexterm:[migration-limit Cluster Options] indexterm:[Cluster Options,migration-limit] The number of migration jobs that the TE is allowed to execute in parallel on a node. | no-quorum-policy | stop | indexterm:[no-quorum-policy Cluster Options] indexterm:[Cluster Options,no-quorum-policy] What to do when the cluster does not have quorum. Allowed values: * ignore - continue all resource management * freeze - continue resource management, but don't recover resources from nodes not in the affected partition * stop - stop all resources in the affected cluster partition * suicide - fence all nodes in the affected cluster partition | symmetric-cluster | TRUE | indexterm:[symmetric-cluster Cluster Options] indexterm:[Cluster Options,symmetric-cluster] Can all resources run on any node by default? | stonith-enabled | TRUE | indexterm:[stonith-enabled Cluster Options] indexterm:[Cluster Options,stonith-enabled] Should failed nodes and nodes with resources that can't be stopped be shot? If you value your data, set up a STONITH device and enable this. If true, or unset, the cluster will refuse to start resources unless one or more STONITH resources have been configured also. | stonith-action | reboot | indexterm:[stonith-action Cluster Options] indexterm:[Cluster Options,stonith-action] Action to send to STONITH device. Allowed values: reboot, off. The value 'poweroff' is also allowed, but is only used for legacy devices. | cluster-delay | 60s | indexterm:[cluster-delay Cluster Options] indexterm:[Cluster Options,cluster-delay] Round trip delay over the network (excluding action execution). The "correct" value will depend on the speed and load of your network and cluster nodes. | stop-orphan-resources | TRUE | indexterm:[stop-orphan-resources Cluster Options] indexterm:[Cluster Options,stop-orphan-resources] Should deleted resources be stopped? | stop-orphan-actions | TRUE | indexterm:[stop-orphan-actions Cluster Options] indexterm:[Cluster Options,stop-orphan-actions] Should deleted actions be cancelled? | start-failure-is-fatal | TRUE | indexterm:[start-failure-is-fatal Cluster Options] indexterm:[Cluster Options,start-failure-is-fatal] When set to FALSE, the cluster will instead use the resource's +failcount+ and value for +resource-failure-stickiness+. | pe-error-series-max | -1 (all) | indexterm:[pe-error-series-max Cluster Options] indexterm:[Cluster Options,pe-error-series-max] The number of PE inputs resulting in ERRORs to save. Used when reporting problems. | pe-warn-series-max | -1 (all) | indexterm:[pe-warn-series-max Cluster Options] indexterm:[Cluster Options,pe-warn-series-max] The number of PE inputs resulting in WARNINGs to save. Used when reporting problems. | pe-input-series-max | -1 (all) | indexterm:[pe-input-series-max Cluster Options] indexterm:[Cluster Options,pe-input-series-max] The number of "normal" PE inputs to save. Used when reporting problems. |========================================================= You can always obtain an up-to-date list of cluster options, including -their default values, by running the pass:[pengine -metadata] command. +their default values, by running the `pengine +metadata` command. == Querying and Setting Cluster Options == indexterm:[Querying Cluster Options] indexterm:[Setting Cluster Options] indexterm:[Cluster Options,Querying] indexterm:[Cluster Options,Setting] Cluster options can be queried and modified using the -pass:[crm_attribute] tool. To get the current +`crm_attribute` tool. To get the current value of +cluster-delay+, simply use: -pass:[crm_attribute --attr-name cluster-delay --get-value] +`crm_attribute --attr-name cluster-delay --get-value` which is more simply written as -pass:[crm_attribute --get-value -n cluster-delay] +`crm_attribute --get-value -n cluster-delay` If a value is found, you'll see a result like this: ======= -pass:[ # crm_attribute --get-value -n cluster-delay] +` # crm_attribute --get-value -n cluster-delay` name=cluster-delay value=60s ======== However, if no value is found, the tool will display an error: ======= -pass:[# crm_attribute --get-value -n clusta-deway] +`# crm_attribute --get-value -n clusta-deway` name=clusta-deway value=(null) Error performing operation: The object/attribute does not exist ======== To use a different value, eg. +30+, simply run: -pass:[crm_attribute --attr-name cluster-delay --attr-value 30s] +`crm_attribute --attr-name cluster-delay --attr-value 30s` To go back to the cluster's default value you can delete the value, for example with this command: -pass:[crm_attribute --attr-name cluster-delay --delete-attr] +`crm_attribute --attr-name cluster-delay --delete-attr` == When Options are Listed More Than Once == If you ever see something like the following, it means that the option you're modifying is present more than once. .Deleting an option that is listed twice ======= -pass:[# crm_attribute --attr-name batch-limit --delete-attr] +`# crm_attribute --attr-name batch-limit --delete-attr` Multiple attributes match name=batch-limit in crm_config: Value: 50 (set=cib-bootstrap-options, id=cib-bootstrap-options-batch-limit) Value: 100 (set=custom, id=custom-batch-limit) Please choose from one of the matches above and supply the 'id' with --attr-id ======= In such cases follow the on-screen instructions to perform the requested action. To determine which value is currently being used by the cluster, please refer to the section on <>. diff --git a/doc/Pacemaker_Explained/en-US/Ch-Resources.txt b/doc/Pacemaker_Explained/en-US/Ch-Resources.txt new file mode 100644 index 0000000000..9033b35ec5 --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ch-Resources.txt @@ -0,0 +1,589 @@ += Cluster Resources = + +== What is a Cluster Resource == + +indexterm:[Resource,Description] + +The role of a resource agent is to abstract the service it provides +and present a consistent view to the cluster, which allows the cluster +to be agnostic about the resources it manages. + +The cluster doesn't need to understand how the resource works because +it relies on the resource agent to do the right thing when given a ++start+, +stop+ or +monitor+ command. + +For this reason it is crucial that resource agents are well tested. + +Typically resource agents come in the form of shell scripts, however +they can be written using any technology (such as C, Python or Perl) +that the author is comfortable with. + +== Supported Resource Classes == + +indexterm:[Resource,Classes] +anchor:s-resource-supported[Supported Resource Classes] + +There are three basic classes of agents supported by Pacemaker. +In order of encouraged usage they are: + +=== Open Cluster Framework === + +indexterm:[Resource,OCF] +indexterm:[OCF,Resources] +indexterm:[Open Cluster Framework,Resources] + +The OCF standard +footnote:[ +http://www.opencf.org/cgi-bin/viewcvs.cgi/specs/ra/resource-agent-api.txt?rev=HEAD - at least as it relates to resource agents. +] footnote:[ +The Pacemaker implementation has been somewhat extended from the OCF +Specs, but none of those changes are incompatible with the original +OCF specification. +] +is basically an extension of the Linux Standard Base conventions for +init scripts to: + +* support parameters, +* make them self describing and +* extensible + +OCF specs have strict definitions of the exit codes that actions must return. +footnote:[ +Included with the cluster is the ocf-tester script, which can be +useful in this regard. +] + +The cluster follows these specifications exactly, and giving the wrong +exit code will cause the cluster to behave in ways you will likely +find puzzling and annoying. In particular, the cluster needs to +distinguish a completely stopped resource from one which is in some +erroneous and indeterminate state. + +Parameters are passed to the script as environment variables, with the +special prefix +OCF_RESKEY_+. So, a parameter which the user thinks +of as ip it will be passed to the script as +OCF_RESKEY_ip+. The +number and purpose of the parameters is completely arbitrary, however +your script should advertise any that it supports using the ++meta-data+ command. + + +The OCF class is the most preferred one as it is an industry standard, +highly flexible (allowing parameters to be passed to agents in a +non-positional manner) and self-describing. + +For more information, see the +http://www.linux-ha.org/wiki/OCF_Resource_Agents[reference] and +xref:ap-ocf[]. + +=== Linux Standard Base === +indexterm:[Resource,LSB] +indexterm:[LSB,Resources] +indexterm:[Linus Standard Base,Resources] + +LSB resource agents are those found in '/etc/init.d'. + +Generally they are provided by the OS/distribution and, in order to be used with the cluster, they must conform to the LSB Spec. +footnote:[ +See +http://refspecs.linux-foundation.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/iniscrptact.html +for the LSB Spec (as it relates to init scripts). +] + +Many distributions claim LSB compliance but ship with broken init +scripts. To see if your init script is LSB-compatible, see the FAQ +entry xref:ap-lsb[]. The most common problems are: + +* Not implementing the status operation at all +* Not observing the correct exit status codes for start/stop/status actions +* Starting a started resource returns an error (this violates the LSB spec) +* Stopping a stopped resource returns an error (this violates the LSB spec) + +=== Legacy Heartbeat === +indexterm:[Resource,Heartbeat (legacy)] +indexterm:[Heartbeat,Legacy Resources] + +Version 1 of Heartbeat came with its own style of resource agents and +it is highly likely that many people have written their own agents +based on its conventions. To enable administrators to continue to use +these agents, they are supported by the new cluster manager +footnote:[ +See http://wiki.linux-ha.org/HeartbeatResourceAgent for more information +] + +=== STONITH === +indexterm:[Resource,STONITH] +indexterm:[STONITH,Resources] + +There is also an additional class, STONITH, which is used exclusively +for fencing related resources. This is discussed later in +xref:ch-stonith[]. + +== Properties == + +These values tell the cluster which script to use for the resource, where to find that script and what standards it conforms to. + +.Properties of a Primitive Resource +[width="95%",cols="1m,6<",options="header",align="center"] +|========================================================= + +|Field +|Description + +|id +indexterm:[id] +|Your name for the resource + +|class +indexterm:[class,Resource Field] +indexterm:[Resource,Field,class] +|The standard the script conforms to. Allowed values: +heartbeat+, +lsb+, +ocf+, +stonith+ + +|type +indexterm:[type,Resource Field] +indexterm:[Resource,Field,type] +|The name of the Resource Agent you wish to use. Eg. _IPaddr_ or _Filesystem_ + +|provider +indexterm:[provider,Resource Field] +indexterm:[Resource,Field,provider] + +|The OCF spec allows multiple vendors to supply the same + ResourceAgent. To use the OCF resource agents supplied with + Heartbeat, you should specify +heartbeat+ here. + +|========================================================= + +Resource definitions can be queried with the `crm_resource` tool. For example + +[source,Bash] +crm_resource --resource Email --query-xml + +might produce: + +.An example LSB resource +[source,XML] + + +[NOTE] +One of the main drawbacks to LSB resources is that they do not allow any parameters! + +Example for an OCF resource: + +.An example OCF resource +[source,XML] +------- + + + + + +------- + +Or, finally for the equivalent legacy Heartbeat resource: + +.An example Heartbeat resource +[source,XML] +------- + + + + + +------- + +[NOTE] +====== +Heartbeat resources take only ordered and unnamed parameters. The +supplied name therefore indicates the order in which they are passed +to the script. Only single digit values are allowed. +====== + +== Resource Options == + +anchor:s-resource-options[Resource Options] +Options are used by the cluster to decide how your resource should +behave and can be easily set using the `--meta` option of the +`crm_resource` command. + +.Options for a Primitive Resource +[width="95%",cols="1m,1,4<",options="header",align="center"] +|========================================================= + +|Field +|Default +|Description + +|priority +|+0+ +|If not all resources can be active, the cluster will stop lower +priority resources in order to keep higher priority ones active. +indexterm:[priority,Resource Option] +indexterm:[Resource,Option,priority] + +|target-role +|+Started+ +|What state should the cluster attempt to keep this resource in? Allowed values: + +* 'Stopped' - Force the resource to be stopped + +* 'Started' - Allow the resource to be started (In the case of + xref:s-resource-multistate[] resources, they will not promoted to + master) + +* 'Master' - Allow the resource to be started and, if appropriate, promoted +indexterm:[target-role,Resource Option] +indexterm:[Resource,Option,target-role] + +|is-managed +|+TRUE+ +|Is the cluster allowed to start and stop the resource? Allowed + values: +true+, +false+ + indexterm:[is-managed,Resource Option] + indexterm:[Resource,Option,is-managed] + +|resource-stickiness +|Inherited +|How much does the resource prefer to stay where it is? Defaults to + the value of +resource-stickiness+ in the +rsc_defaults+ section + indexterm:[resource-stickiness,Resource Option] + indexterm:[Resource,Option,resource-stickiness] + +|migration-threshold +|+INFINITY+ (disabled) + +|How many failures may occur for this resource on a node, before this + node is marked ineligible to host this resource. + indexterm:[migration-threshold,Resource Option] + indexterm:[Resource,Option,migration-threshold] + +|failure-timeout +|+0+ (disabled) +|How many seconds to wait before acting as if the failure had not + occurred, and potentially allowing the resource back to the node on + which it failed. + indexterm:[failure-timeout,Resource Option] + indexterm:[Resource,Option,failure-timeout] + +|multiple-active +|+stop_start+ +|What should the cluster do if it ever finds the resource active on + more than one node. Allowed values: + +* 'block' - mark the resource as unmanaged + +* 'stop_only' - stop all active instances and leave them that way + +* 'stop_start' - stop all active instances and start the resource in + one location only + +indexterm:[multiple-active,Resource Option] +indexterm:[Resource,Option,multiple-active] + +|========================================================= + +If you performed the following commands on the previous LSB Email resource + +[source,Bash] +------- +crm_resource --meta --resource Email --set-parameter priority --property-value 100 +crm_resource --meta --resource Email --set-parameter multiple-active --property-value block +------- + +the resulting resource definition would be + +.An LSB resource with cluster options +[source,XML] +------- + + + + + + +------- + +== Setting Global Defaults for Resource Options == + +anchor:s-resource-defaults[Resource Defaults] +To set a default value for a resource option, simply add it to the ++rsc_defaults+ section with `crm_attribute`. Thus, + +[source,Bash] +crm_attribute --type rsc_defaults --attr-name is-managed --attr-value false + +would prevent the cluster from starting or stopping any of the +resources in the configuration (unless of course the individual +resources were specifically enabled and had +is-managed+ set to ++true+). + +== Instance Attributes == + +The scripts of some resource classes (LSB not being one of them) can +be given parameters which determine how they behave and which instance +of a service they control. + +If your resource agent supports parameters, you can add them with the +`crm_resource` command. For instance + +[source,Bash] +crm_resource --resource Public-IP --set-parameter ip --property-value 1.2.3.4 + +would create an entry in the resource like this: + +.An example OCF resource with instance attributes +[source,XML] +------- + + + + + +------- + +For an OCF resource, the result would be an environment variable +called +OCF_RESKEY_ip+ with a value of +1.2.3.4+. + +The list of instance attributes supported by an OCF script can be +found by calling the resource script with the `meta-data` command. +The output contains an XML description of all the supported +attributes, their purpose and default values. + +.Displaying the metadata for the Dummy resource agent template +[source,XML] +------- +# export OCF_ROOT=/usr/lib/ocf +# $OCF_ROOT/resource.d/pacemaker/Dummy meta-data + + + + + 1.0 + + + This is a Dummy Resource Agent. It does absolutely nothing except + keep track of whether its running or not. + Its purpose in life is for testing and to serve as a template for RA writers. + + Dummy resource agent + + + + + Location to store the resource state in. + + State file + + + + + + Dummy attribute that can be changed to cause a reload + + Dummy attribute that can be changed to cause a reload + + + + + + + + + + + + + + + +------- + +== Resource Operations == + +=== Monitoring Resources for Failure === + + +By default, the cluster will not ensure your resources are still +healthy. To instruct the cluster to do this, you need to add a ++monitor+ operation to the resource's definition. + +.An OCF resource with a recurring health check +[source,XML] +------- + + + + + + + + +------- + +.Properties of an Operation +[width="95%",cols="1m,6<",options="header",align="center"] +|========================================================= + +|Field +|Description + +|id +|Your name for the action. Must be unique. + +|name +|The action to perform. Common values: +monitor+, +start+, +stop+ + +|interval + +|How frequently (in seconds) to perform the operation. Default value: + +0+, meaning never. + +|timeout +|How long to wait before declaring the action has failed. + +|requires + +|What conditions need to be satisfied before this action + occurs. Allowed values: + +* 'nothing' - The cluster may start this resource at any time + +* 'quorum' - The cluster can only start this resource if a majority of + the configured nodes are active + +* 'fencing' - The cluster can only start this resource if a majority + of the configured nodes are active _and_ any failed or unknown nodes + have been powered off. + +STONITH resources default to +nothing+, and all others default to ++fencing+ if STONITH is enabled and +quorum+ otherwise. + +|on-fail +|The action to take if this action ever fails. Allowed values: + +* 'ignore' - Pretend the resource did not fail + +* 'block' - Don't perform any further operations on the resource + +* 'stop' - Stop the resource and do not start it elsewhere + +* 'restart' - Stop the resource and start it again (possibly on a different node) + +* 'fence' - STONITH the node on which the resource failed + +* 'standby' - Move _all_ resources away from the node on which the resource failed + +The default for the +stop+ operation is +fence+ when STONITH is +enabled and +block+ otherwise. All other operations default to +stop+. + +|enabled +|If +false+, the operation is treated as if it does not exist. Allowed + values: +true+, +false+ + +|========================================================= + + +=== Setting Global Defaults for Operations === + +anchor:s-operation-defaults[Operation Defaults] +To set a default value for a operation option, simply add it to the ++op_defaults+ section with `crm_attribute`. Thus, + +[source,Bash] +crm_attribute --type op_defaults --attr-name timeout --attr-value 20s + + +would default each operation's +timeout+ to 20 seconds. If an +operation's definition also includes a value for +timeout+, then that +value would be used instead (for that operation only). + +==== When Resources Take a Long Time to Start/Stop ==== + +There are a number of implicit operations that the cluster will always +perform - +start+, +stop+ and a non-recurring +monitor+ operation +(used at startup to check the resource isn't already active). If one +of these is taking too long, then you can create an entry for them and +simply specify a new value. + +.An OCF resource with custom timeouts for its implicit actions +[source,XML] +------- + + + + + + + + + + +------- + +==== Multiple Monitor Operations ==== + +Provided no two operations (for a single resource) have the same name +and interval you can have as many monitor operations as you like. In +this way you can do a superficial health check every minute and +progressively more intense ones at higher intervals. + +To tell the resource agent what kind of check to perform, you need to +provide each monitor with a different value for a common parameter. +The OCF standard creates a special parameter called +OCF_CHECK_LEVEL+ +for this purpose and dictates that it is _"made available to the +resource agent without the normal +OCF_RESKEY+ prefix"_. + +Whatever name you choose, you can specify it by adding an ++instance_attributes+ block to the op tag. Note that it is up to each +resource agent to look for the parameter and decide how to use it. + +.An OCF resource with two recurring health checks, performing different levels of checks - specified via +OCF_CHECK_LEVEL+. +[source,XML] +------- + + + + + + + + + + + + + + + + + +------- + +==== Disabling a Monitor Operation ==== + +The easiest way to stop a recurring monitor is to just delete it. +However, there can be times when you only want to disable it +temporarily. In such cases, simply add +enabled="false"+ to the +operation's definition. + +.Example of an OCF resource with a disabled health check +[source,XML] +------- + + + + + + + + +------- + +This can be achieved from the command-line by executing + +[source,Bash] +cibadmin -M -X ‘' + +Once you've done whatever you needed to do, you can then re-enable it with + +[source,Bash] +cibadmin -M -X ‘' diff --git a/doc/Pacemaker_Explained/en-US/Ch-Resources.xml b/doc/Pacemaker_Explained/en-US/Ch-Resources.xml deleted file mode 100644 index 2075048f8d..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ch-Resources.xml +++ /dev/null @@ -1,522 +0,0 @@ - - Cluster Resources -
- What is a Cluster Resource - ResourceDescription - - The role of a resource agent is to abstract the service it provides and present a consistent view to the cluster, which allows the cluster to be agnostic about the resources it manages. - The cluster doesn't need to understand how the resource works because it relies on the resource agent to do the right thing when given a start, stop or monitor command. - - For this reason it is crucial that resource agents are well tested. - Typically resource agents come in the form of shell scripts, however they can be written using any technology (such as C, Python or Perl) that the author is comfortable with. -
-
- Supported Resource Classes - ResourceClasses - - There are three basic classes of agents supported by Pacemaker. - In order of encouraged usage they are: - -
- Open Cluster Framework - ResourceOCF - OCFResources - Open Cluster FrameworkResources - The OCF Spec - at least as it relates to resource agents.'Note: The Pacemaker implementation has been somewhat extended from the OCF Specs, but none of those changes are incompatible with the original OCF specification. is basically an extension of the Linux Standard Base conventions for init scripts to - - support parameters, - make them self describing and - extensible - - - OCF specs have strict definitions of the exit codes that actions must return - Included with the cluster is the ocf-tester script, which can be useful in this regard. - . - The cluster follows these specifications exactly, and giving the wrong exit code will cause the cluster to behave in ways you will likely find puzzling and annoying. - In particular, the cluster needs to distinguish a completely stopped resource from one which is in some erroneous and indeterminate state. - - - Parameters are passed to the script as environment variables, with the special prefix OCF_RESKEY_. - So, a parameter which the user thinks of as ip it will be passed to the script as OCF_RESKEY_ip. - The number and purpose of the parameters is completely arbitrary, however your script should advertise any that it supports using the meta-data command. - - The OCF class is the most preferred one as it is an industry standard, highly flexible (allowing parameters to be passed to agents in a non-positional manner) and self-describing. - For more information, see the reference and . -
-
- Linux Standard Base - ResourceLSB - LSBResources - Linus Standard BaseResources - - LSB resource agents are those typically found in /etc/init.d. - Generally they are provided by the OS/distribution and, in order to be used with the cluster, they must conform to the LSB Spec - See - for the LSB Spec (as it relates to init scripts). - . - - - Many distributions claim LSB compliance but ship with broken init scripts. - To see if your init script is LSB-compatible, see the FAQ entry . - The most common problems are: - - - Not implementing the status operation at all - Not observing the correct exit status codes for start/stop/status actions - Starting a started resource returns an error (this violates the LSB spec) - Stopping a stopped resource returns an error (this violates the LSB spec) - -
-
- Legacy Heartbeat - ResourceHeartbeat (legacy) - HeartbeatLegacy Resources - - Version 1 of Heartbeat came with its own style of resource agents and it is highly likely that many people have written their own agents based on its conventions. - To enable administrators to continue to use these agents, they are supported by the new cluster manager - See for more information.. - -
-
- STONITH - ResourceSTONITH - STONITHResources - - There is also an additional class, STONITH, which is used exclusively for fencing related resources. - This is discussed later in . - -
-
-
- Properties - These values tell the cluster which script to use for the resource, where to find that script and what standards it conforms to. - - Properties of a Primitive Resource - - - - - - Field - Description - - - - - - id - id - Your name for the resource - - - - classResource Field - ResourceFieldclass - class - The standard the script conforms to. Allowed values: heartbeat, lsb, ocf, stonith - - - - typeResource Field - ResourceFieldtype - type - The name of the Resource Agent you wish to use. Eg. IPaddr or Filesystem - - - - providerResource Field - ResourceFieldprovider - provider - The OCF spec allows multiple vendors to supply the same ResourceAgent. To use the OCF resource agents supplied with Heartbeat, you should specify heartbeat here. - - - -
- Resource definitions can be queried with the crm_resource tool. For example - crm_resource --resource Email --query-xml - might produce - - An example LSB resource - ]]> - - - - One of the main drawbacks to LSB resources is that they do not allow any parameters! - - - Example for an OCF resource: - - An example OCF resource - - - - - ]]> - - Or, finally for the equivalent legacy Heartbeat resource: - - An example Heartbeat resource - - - - - ]]> - - - - Heartbeat resources take only ordered and unnamed parameters. - The supplied name therefore indicates the order in which they are passed to the script. - Only single digit values are allowed. - - - -
-
- Resource Options - Options are used by the cluster to decide how your resource should behave and can be easily set using the --meta option of the crm_resource command. - - Options for a Primitive Resource - - - - - - - Field - Default - Description - - - - priorityResource Option - ResourceOptionpriority - priority - 0 - If not all resources can be active, the cluster will stop lower priority resources in order to keep higher priority ones active. - - - - target-roleResource Option - ResourceOptiontarget-role - target-role - Started - - What state should the cluster attempt to keep this resource in? Allowed values: - - Stopped - Force the resource to be stopped - Started - Allow the resource to be started (In the case of multi-state resources, they will not promoted to master) - Master - Allow the resource to be started and, if appropriate, promoted - - - - - - is-managedResource Option - ResourceOptionis-managed - is-managed - TRUE - - Is the cluster allowed to start and stop the resource? - Allowed values: true, false - - - - - resource-stickinessResource Option - ResourceOptionresource-stickiness - resource-stickiness - Inherited - - How much does the resource prefer to stay where it is? - Defaults to the value of resource-stickiness in the rsc_defaults section - - - - - migration-thresholdResource Option - ResourceOptionmigration-threshold - migration-threshold - INFINITY (disabled) - How many failures may occur for this resource on a node, before this node is marked ineligible to host this resource. - - - - failure-timeoutResource Option - ResourceOptionfailure-timeout - failure-timeout - 0 (disabled) - How many seconds to wait before acting as if the failure had not occurred, and potentially allowing the resource back to the node on which it failed. - - - - multiple-activeResource Option - ResourceOptionmultiple-active - multiple-active - stop_start - - What should the cluster do if it ever finds the resource active on more than one node. Allowed values: - - block - mark the resource as unmanaged - stop_only - stop all active instances and leave them that way - stop_start - stop all active instances and start the resource in one location only - - - - - -
- If you performed the following commands on the previous LSB Email resource - crm_resource --meta --resource Email --set-parameter priority --property-value 100 - crm_resource --meta --resource Email --set-parameter multiple-active --property-value block - - the resulting resource definition would be - - An LSB resource with cluster options - - - - - - ]]> - -
-
- Setting Global Defaults for Resource Options - To set a default value for a resource option, simply add it to the rsc_defaults section with crm_attribute. Thus, - crm_attribute --type rsc_defaults --attr-name is-managed --attr-value false - would prevent the cluster from starting or stopping any of the resources in the configuration (unless of course the individual resources were specifically enabled and had is-managed set to true). -
-
- Instance Attributes - The scripts of some resource classes (LSB not being one of them) can be given parameters which determine how they behave and which instance of a service they control. - If your resource agent supports parameters, you can add them with the crm_resource command. For instance - crm_resource --resource Public-IP --set-parameter ip --property-value 1.2.3.4 - would create an entry in the resource like this: - - An example OCF resource with instance attributes - - - - - ]]> - - For an OCF resource, the result would be an environment variable called OCF_RESKEY_ip with a value of 1.2.3.4. - - The list of instance attributes supported by an OCF script can be found by calling the resource script with the meta-data command. - The output contains an XML description of all the supported attributes, their purpose and default values. - - - Displaying the metadata for the Dummy resource agent template - export OCF_ROOT=/usr/lib/ocf; $OCF_ROOT/resource.d/pacemaker/Dummy meta-data - - - - 1.0 - - - This is a Dummy Resource Agent. It does absolutely nothing except - keep track of whether its running or not. - Its purpose in life is for testing and to serve as a template for RA writers. - - Dummy resource agent - - - - - Location to store the resource state in. - - State file - - - - - - Dummy attribute that can be changed to cause a reload - - Dummy attribute that can be changed to cause a reload - - - - - - - - - - - - - - - ]]> - -
-
- Resource Operations -
- Monitoring Resources for Failure - - By default, the cluster will not ensure your resources are still healthy. - To instruct the cluster to do this, you need to add a monitor operation to the resource's definition. - - - An OCF resource with a recurring health check - - - - - - - - ]]> - - - Properties of an Operation - - - - - - Field - Description - - - id - Your name for the action. Must be unique. - - - name - The action to perform. Common values: monitor, start, stop - - - interval - How frequently (in seconds) to perform the operation. Default value: 0, meaning never. - - - timeout - How long to wait before declaring the action has failed. - - - requires - - What conditions need to be satisfied before this action occurs. Allowed values: - - nothing - The cluster may start this resource at any time - quorum - The cluster can only start this resource if a majority of the configured nodes are active - fencing - The cluster can only start this resource if a majority of the configured nodes are active and any failed or unknown nodes have been powered off. - - STONITH resources default to nothing, and all others default to fencing if STONITH is enabled and quorum otherwise. - - - - on-fail - - The action to take if this action ever fails. Allowed values: - - ignore - Pretend the resource did not fail - block - Don't perform any further operations on the resource - stop - Stop the resource and do not start it elsewhere - restart - Stop the resource and start it again (possibly on a different node) - fence - STONITH the node on which the resource failed - standby - Move all resources away from the node on which the resource failed - - The default for the stop operation is fence when STONITH is enabled and block otherwise. All other operations default to stop. - - - - enabled - If false, the operation is treated as if it does not exist. Allowed values: true, false - - - -
-
-
-
- Setting Global Defaults for Operations - To set a default value for a operation option, simply add it to the op_defaults section with crm_attribute. Thus, - crm_attribute --type op_defaults --attr-name timeout --attr-value 20s - - would default each operation's timeout to 20 seconds. - If an operation's definition also includes a value for timeout, then that value would be used instead (for that operation only). - -
- When Resources Take a Long Time to Start/Stop - - There are a number of implicit operations that the cluster will always perform - start, stop and a non-recurring monitor operation (used at startup to check the resource isn't already active). - If one of these is taking too long, then you can create an entry for them and simply specify a new value. - - - An OCF resource with custom timeouts for its implicit actions - - - - - - - - - - ]]> - -
-
- Multiple Monitor Operations - - Provided no two operations (for a single resource) have the same name and interval you can have as many monitor operations as you like. - In this way you can do a superficial health check every minute and progressively more intense ones at higher intervals. - - - To tell the resource agent what kind of check to perform, you need to provide each monitor with a different value for a common parameter. - The OCF standard creates a special parameter called OCF_CHECK_LEVEL for this purpose and dictates that it is "made available to the resource agent without the normal OCF_RESKEY_ prefix". - - - Whatever name you choose, you can specify it by adding an instance_attributes block to the op tag. - Note that it is up to each resource agent to look for the parameter and decide how to use it. - - - An OCF resource with two recurring health checks, performing different levels of checks - specified via <literal>OCF_CHECK_LEVEL</literal>. - - - - - - - - - - - - - - - - - ]]> - -
-
- Disabling a Monitor Operation - - The easiest way to stop a recurring monitor is to just delete it. - However, there can be times when you only want to disable it temporarily. - In such cases, simply add enabled="false" to the operation's definition. - - - Example of an OCF resource with a disabled health check - - - - - - - - ]]> - - This can be achieved from the command-line by executing - cibadmin -M -X ‘<op id="public-ip-check" enabled="false"/>' - Once you've done whatever you needed to do, you can then re-enable it with - cibadmin -M -X ‘<op id="public-ip-check" enabled="true"/>' -
-
- diff --git a/doc/Pacemaker_Explained/en-US/Ch-Rules.txt b/doc/Pacemaker_Explained/en-US/Ch-Rules.txt new file mode 100644 index 0000000000..e8521178f3 --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ch-Rules.txt @@ -0,0 +1,512 @@ += Rules = + +anchor:ch-rules[Rules] +Rules can be used to make your configuration more dynamic. One common +example is to set one value for +resource-stickiness+ during working +hours, to prevent resources from being moved back to their most +preferred location, and another on weekends when no-one is around to +notice an outage. + +Another use of rules might be to assign machines to different +processing groups (using a node attribute) based on time and to then +use that attribute when creating location constraints. + +Each rule can contain a number of expressions, date-expressions and +even other rules. The results of the expressions are combined based +on the rule's +boolean-op+ field to determine if the rule ultimately +evaluates to +true+ or +false+. What happens next depends on the +context in which the rule is being used. + +.Properties of a Rule +[width="95%",cols="1m,5<",options="header",align="center"] +|========================================================= + +|Field +|Description + +|role +indexterm:[role Rule Property] +indexterm:[Rule,Properties,role] +|Limits the rule to apply only when the resource is in that + role. Allowed values: _Started_, +Slave,+ and +Master+. NOTE: A rule + with +role="Master"+ can not determine the initial location of a + clone instance. It will only affect which of the active instances + will be promoted. + +|score +indexterm:[score,Rule Property] +indexterm:[Rule,Properties,score] +|The score to apply if the rule evaluates to +true+. Limited to use in + rules that are part of location constraints. + +|score-attribute +indexterm:[score-attribute Rule Property] +indexterm:[Rule,Properties,score-attribute] +|The node attribute to look up and use as a score if the rule + evaluates to +true+. Limited to use in rules that are part of + location constraints. + +|boolean-op +indexterm:[boolean-op Rule Property] +indexterm:[Rule,Properties,boolean-op] +|How to combine the result of multiple expression objects. Allowed + values: _and_ and +or+. + +|========================================================= + +== Node Attribute Expressions == + +indexterm:[Node,Attribute Expressions] + +Expression objects are used to control a resource based on the +attributes defined by a node or nodes. In addition to any attributes +added by the administrator, each node has a built-in node attribute +called +#uname+ that can also be used. + +.Properties of an Expression +[width="95%",cols="1m,5<",options="header",align="center"] +|========================================================= + +|Field +|Description + +|value +indexterm:[value Expression Property] +indexterm:[Expression Properties,value] +|User supplied value for comparison + +|attribute +indexterm:[attribute Expression Property] +indexterm:[Expression Properties,attribute] +|The node attribute to test + +|type +indexterm:[type,Expression Property] +indexterm:[Expression Properties,type] +|Determines how the value(s) should be tested. Allowed values: + _string_, +integer+, +version+ + +|operation +indexterm:[operation Expression Property] +indexterm:[Expression Properties,operation] +|The comparison to perform. Allowed values: + +* +lt+ - True if the node attribute's value is less than +value+ + +* +gt+ - True if the node attribute's value is greater than +value+ + +* +lte+ - True if the node attribute's value is less than or equal to +value+ + +* +gte+ - True if the node attribute's value is greater than or equal to +value+ + +* +eq+ - True if the node attribute's value is equal to +value+ + +* +ne+ - True if the node attribute's value is not equal to +value+ + +* +defined+ - True if the node has the named attribute + +* +not_defined+ - True if the node does not have the named attribute + +|========================================================= + +== Time/Date Based Expressions == + +indexterm:[Time Based Expressions] +indexterm:[Expression,Time/Date Based] + +As the name suggests, +date_expressions+ are used to control a +resource or cluster option based on the current date/time. They can +contain an optional +date_spec+ and/or +duration+ object depending on +the context. + +.Properties of a Date Expression +[width="95%",cols="1m,5<",options="header",align="center"] +|========================================================= +|Field +|Description + +|start +|A date/time conforming to the ISO8601 specification. + +|end +|A date/time conforming to the ISO8601 specification. Can be inferred + by supplying a value for +start+ and a +duration+. + +|operation +|Compares the current date/time with the start and/or end date, + depending on the context. Allowed values: + +* +gt+ - True if the current date/time is after +start+ + +* +lt+ - True if the current date/time is before +end+ + +* +in-range+ - True if the current date/time is after +start+ and before +end+ + +* +date-spec+ - performs a cron-like comparison to the current date/time + +|========================================================= + +[NOTE] +====== +Because the comparisons (except for +date_spec+) include the time, the ++eq+, +neq+, +gte+ and +lte+ operators have not been +implemented. +====== + +=== Date Specifications === +indexterm:[Date Specifications] + ++date_spec+ objects are used to create cron-like expressions relating +to time. Each field can contain a single number or a single range. +Instead of defaulting to zero, any field not supplied is ignored. + +For example, +monthdays="1"+ matches the first day of every month and ++hours="09-17"+ matches the hours between 9am and 5pm (inclusive). +However, at this time one cannot specify +weekdays="1,2"+ or ++weekdays="1-2,5-6"+ since they contain multiple ranges. Depending on +demand, this may be implemented in a future release. + +.Properties of a Date Spec +[width="95%",cols="1m,5<",options="header",align="center"] +|========================================================= + +|Field +|Description + +|id +indexterm:[id,Date Spec Property] +indexterm:[Date Spec Properties,id] +|A unique name for the date + +|hours +indexterm:[hours Date Spec Property] +indexterm:[Date Spec Properties,hours] +|Allowed values: 0-23 + +|monthdays +indexterm:[monthdays Date Spec Property] +indexterm:[Date Spec Properties,monthdays] +|Allowed values: 0-31 (depending on month and year) + +|weekdays +indexterm:[weekdays Date Spec Property] +indexterm:[Date Spec Properties,weekdays] +|Allowed values: 1-7 (1=Monday, 7=Sunday) + +|yeardays +indexterm:[yeardays Date Spec Property] +indexterm:[Date Spec Properties,yeardays] +|Allowed values: 1-366 (depending on the year) + +|months +indexterm:[months Date Spec Property] +indexterm:[Date Spec Properties,months] +|Allowed values: 1-12 + +|weeks +indexterm:[weeks Date Spec Property] +indexterm:[Date Spec Properties,weeks] +|Allowed values: 1-53 (depending on weekyear) + +|years +indexterm:[years Date Spec Property] +indexterm:[Date Spec Properties,years] +|Year according the Gregorian calendar + +|weekyears +indexterm:[weekyears Date Spec Property] +indexterm:[Date Spec Properties,weekyears] +|May differ from Gregorian years; Eg. +2005-001 Ordinal+ is also + +2005-01-01 Gregorian+ is also +2004-W53-6 Weekly+ + +|moon +indexterm:[moon Date Spec Property] +indexterm:[Date Spec Properties,moon] +|Allowed values: 0-7 (0 is new, 4 is full moon). Seriously, you can + use this. This was implemented to demonstrate the ease with which new + comparisons could be added. + +|========================================================= + +=== Durations === +indexterm:[Durations Expressions] +indexterm:[Expressions,Durations] + +Durations are used to calculate a value for +end+ when one is not +supplied to in_range operations. They contain the same fields as ++date_spec+ objects but without the limitations (ie. you can have a +duration of 19 months). Like +date_specs+, any field not supplied is +ignored. + +== Sample Time Based Expressions == + +A small sample of how time based expressions can be used. + +//// +These should have source,XML directives +But then the title doesn't appear. +WTF? +//// + +.True if now is any time in the year 2005 +---- + + + + + +---- + +.Equivalent expression +---- + + + + + +---- + +.9am-5pm, Mon-Friday +------- + + + + + +------- + +Please note that the +16+ matches up to +16:59:59+, as the numeric +value (hour) still matches! + +.9am-6pm, Mon-Friday, or all day saturday +------- + + + + + + + + +------- + +.9am-5pm or 9pm-12pm, Mon-Friday +------- + + + + + + + + + + + + + +------- + +.Mondays in March 2005 +------- + + + + + + +------- + +[NOTE] +====== +Because no time is specified, 00:00:00 is implied. + +This means that the range includes all of 2005-03-01 but none of 2005-04-01. +You may wish to write +end="2005-03-31T23:59:59"+ to avoid confusion. +====== + +.A full moon on Friday the 13th +------- + + + + + +------- + +== Using Rules to Determine Resource Location == +indexterm:[Rule,Determine Resource Location] +indexterm:[Resource,Location, Determine by Rules] + +If the constraint's outer-most rule evaluates to +false+, the cluster +treats the constraint as if it was not there. When the rule evaluates +to +true+, the node's preference for running the resource is updated +with the score associated with the rule. + +If this sounds familiar, its because you have been using a simplified +syntax for location constraint rules already. Consider the following +location constraint: + +.Prevent myApacheRsc from running on c001n03 +------- + +------- + +This constraint can be more verbosely written as: + +.Prevent myApacheRsc from running on c001n03 - expanded version +------- + + + + + +------- + +The advantage of using the expanded form is that one can then add +extra clauses to the rule, such as limiting the rule such that it only +applies during certain times of the day or days of the week (this is +discussed in subsequent sections). + + +It also allows us to match on node properties other than its name. If +we rated each machine's CPU power such that the cluster had the +following nodes section: + +.A sample nodes section for use with score-attribute +------- + + + + + + + + + + + + +------- + +then we could prevent resources from running on underpowered machines with the rule + +[source,XML] +------- + + + +------- + +=== Using +score-attribute+ Instead of +score+ === + +When using +score-attribute+ instead of +score+, each node matched by +the rule has its score adjusted differently, according to its value +for the named node attribute. Thus, in the previous example, if a +rule used +score-attribute="cpu_mips"+, +c001n01+ would have its +preference to run the resource increased by +1234+ whereas +c001n02+ +would have its preference increased by +5678+. + +== Using Rules to Control Resource Options == + +Often some cluster nodes will be different from their peers; sometimes +these differences (the location of a binary or the names of network +interfaces) require resources to be configured differently depending +on the machine they're hosted on. + +By defining multiple +instance_attributes+ objects for the resource +and adding a rule to each, we can easily handle these special cases. + +In the example below, +mySpecialRsc+ will use eth1 and port 9999 when +run on +node1+, eth2 and port 8888 on +node2+ and default to eth0 and +port 9999 for all other nodes. + +.Defining different resource options based on the node name +------- + + + + + + + + + + + + + + + + + + + +------- + +The order in which +instance_attributes+ objects are evaluated is +determined by their score (highest to lowest). If not supplied, score +defaults to zero and objects with an equal score are processed in +listed order. If the +instance_attributes+ object does not have a ++rule+ or has a +rule+ that evaluates to +true+, then for any +parameter the resource does not yet have a value for, the resource +will use the parameter values defined by the +instance_attributes+ +object. + +== Using Rules to Control Cluster Options == +indexterm:[Rule,Controlling Cluster Options] +indexterm:[Cluster Options,Controlled by Rules] + +Controlling cluster options is achieved in much the same manner as +specifying different resource options on different nodes. + +The difference is that because they are cluster options, one cannot +(or should not, because they won't work) use attribute based +expressions. The following example illustrates how to set a different ++resource-stickiness+ value during and outside of work hours. This +allows resources to automatically move back to their most preferred +hosts, but at a time that (in theory) does not interfere with business +activities. + +.Change +resource-stickiness+ during working hours +------- + + + + + + + + + + + + + +------- + +== Ensuring Time Based Rules Take Effect == + +anchor:s-rules-recheck[Ensuring Time Based Rules Take Effect] +A Pacemaker cluster is an event driven system. As such, it won't +recalculate the best place for resources to run in unless something +(like a resource failure or configuration change) happens. This can +mean that a location constraint that only allows resource X to run +between 9am and 5pm is not enforced. + +If you rely on time based rules, it is essential that you set the ++cluster-recheck-interval+ option. This tells the cluster to +periodically recalculate the ideal state of the cluster. For example, +if you set +cluster-recheck-interval=5m+, then sometime between 9:00 +and 9:05 the cluster would notice that it needs to start resource X, +and between 17:00 and 17:05 it would realize that X needed to be +stopped. + +Note that the timing of the actual start and stop actions depends on +what else needs to be performed first. diff --git a/doc/Pacemaker_Explained/en-US/Ch-Rules.xml b/doc/Pacemaker_Explained/en-US/Ch-Rules.xml deleted file mode 100644 index b8c3050b78..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ch-Rules.xml +++ /dev/null @@ -1,463 +0,0 @@ - - Rules - - Rules can be used to make your configuration more dynamic. - One common example is to set one value for resource-stickiness during working hours, to prevent resources from being moved back to their most preferred location, and another on weekends when no-one is around to notice an outage. - - Another use of rules might be to assign machines to different processing groups (using a node attribute) based on time and to then use that attribute when creating location constraints. - - Each rule can contain a number of expressions, date-expressions and even other rules. - The results of the expressions are combined based on the rule's boolean-op field to determine if the rule ultimately evaluates to true or false. - What happens next depends on the context in which the rule is being used. - - - Properties of a Rule - - - - - - Field - Description - - - - - role Rule Property - RulePropertiesrole - role - Limits the rule to apply only when the resource is in that role. Allowed values: Started, Slave, and Master. NOTE: A rule with role="Master" can not determine the initial location of a clone instance. It will only affect which of the active instances will be promoted. - - - scoreRule Property - RulePropertiesscore - score - The score to apply if the rule evaluates to true. Limited to use in rules that are part of location constraints. - - - score-attribute Rule Property - RulePropertiesscore-attribute - score-attribute - The node attribute to look up and use as a score if the rule evaluates to true. Limited to use in rules that are part of location constraints. - - - boolean-op Rule Property - RulePropertiesboolean-op - boolean-op - How to combine the result of multiple expression objects. Allowed values: and and or. - - - -
-
- <indexterm significance="preferred"><primary>Node</primary><secondary>Attribute Expressions</secondary></indexterm>Node Attribute Expressions - Expression objects are used to control a resource based on the attributes defined by a node or nodes. -In addition to any attributes added by the administrator, each node has a built-in node attribute called #uname that can also be used. - - Properties of an Expression - - - - - - Field - Description - - - value Expression Property - Expression Propertiesvalue - value - User supplied value for comparison - - - attribute Expression Property - Expression Propertiesattribute - attribute - The node attribute to test - - - typeExpression Property - Expression Propertiestype - type - Determines how the value(s) should be tested. Allowed values: string, integer, version - - - operation Expression Property - Expression Propertiesoperation - operation - - The comparison to perform. Allowed values: - - lt - True if the node attribute's value is less than value - gt - True if the node attribute's value is greater than value - lte - True if the node attribute's value is less than or equal to value - gte - True if the node attribute's value is greater than or equal to value - eq - True if the node attribute's value is equal to value - ne - True if the node attribute's value is not equal to value - defined - True if the node has the named attribute - not_defined - True if the node does not have the named attribute - - - - - -
-
-
- <indexterm significance="preferred"><primary>Time Based Expressions</primary></indexterm> - <indexterm significance="preferred"><primary>Expression</primary><secondary>Time/Date Based</secondary></indexterm> - Time/Date Based Expressions - - As the name suggests, date_expressions are used to control a resource or cluster option based on the current date/time. - They can contain an optional date_spec and/or duration object depending on the context. - - - Properties of a Date Expression - - - - - - Field - Description - - - start - A date/time conforming to the ISO8601 specification. - - - end - A date/time conforming to the ISO8601 specification. Can be inferred by supplying a value for start and a duration. - - - operation - - Compares the current date/time with the start and/or end date, depending on the context. Allowed values: - - gt - True if the current date/time is after start - lt - True if the current date/time is before end - in-range - True if the current date/time is after start and before end - date-spec - performs a cron-like comparison to the current date/time - - - - - -
- Because the comparisons (except for date_spec) include the time, the eq, neq, gte and lte operators have not been implemented. -
- <indexterm significance="preferred"><primary>Date Specifications</primary></indexterm> - Date Specifications - - date_spec objects are used to create cron-like expressions relating to time. - Each field can contain a single number or a single range. - Instead of defaulting to zero, any field not supplied is ignored. - - - For example, monthdays="1" matches the first day of every month and hours="09-17" matches the hours between 9am and 5pm (inclusive). - However, at this time one cannot specify weekdays="1,2" or weekdays="1-2,5-6" since they contain multiple ranges. - Depending on demand, this may be implemented in a future release. - - - Properties of a Date Spec - - - - - - Field - Description - - - - - idDate Spec Property - Date Spec Propertiesid - id - A unique name for the date - - - hours Date Spec Property - Date Spec Propertieshours - hours - Allowed values: 0-23 - - - monthdays Date Spec Property - Date Spec Propertiesmonthdays - monthdays - Allowed values: 0-31 (depending on month and year) - - - weekdays Date Spec Property - Date Spec Propertiesweekdays - weekdays - Allowed values: 1-7 (1=Monday, 7=Sunday) - - - yeardays Date Spec Property - Date Spec Propertiesyeardays - yeardays - Allowed values: 1-366 (depending on the year) - - - months Date Spec Property - Date Spec Propertiesmonths - months - Allowed values: 1-12 - - - weeks Date Spec Property - Date Spec Propertiesweeks - weeks - Allowed values: 1-53 (depending on weekyear) - - - years Date Spec Property - Date Spec Propertiesyears - years - Year according the Gregorian calendar - - - weekyears Date Spec Property - Date Spec Propertiesweekyears - weekyears - - May differ from Gregorian years; Eg. 2005-001 Ordinal is also 2005-01-01 Gregorian is also 2004-W53-6 Weekly - - - - moon Date Spec Property - Date Spec Propertiesmoon - moon - Allowed values: 0-7 (0 is new, 4 is full moon). Seriously, you can use this. This was implemented to demonstrate the ease with which new comparisons could be added. - - - -
-
-
- <indexterm significance="preferred"><primary>Durations Expressions</primary></indexterm> - <indexterm significance="preferred"><primary>Expressions</primary><secondary>Durations</secondary></indexterm> - Durations - - Durations are used to calculate a value for end when one is not supplied to in_range operations. - They contain the same fields as date_spec objects but without the limitations (ie. you can have a duration of 19 months). - Like date_specs, any field not supplied is ignored. - -
- Sample Time Based Expressions - - True if now is any time in the year 2005 - - - - - ]]> - - - Equivalent expression. - - - - - ]]> - - - 9am-5pm, Mon-Friday - - - - - ]]> - - Please note that the 16 matches up to 16:59:59, as the numeric value (hour) still matches! - - 9am-6pm, Mon-Friday, or all day saturday - - - - - - - - ]]> - - - 9am-5pm or 9pm-12pm, Mon-Friday - - - - - - - - - - - - - ]]> - - - Mondays in March 2005 - - - - - - ]]> - - NOTE: Because no time is specified, 00:00:00 is implied. - This means that the range includes all of 2005-03-01 but none of 2005-04-01. - You may wish to write end="2005-03-31T23:59:59" to avoid confusion. - - A full moon on Friday the 13th - - - - - ]]> - -
-
-
-
- <indexterm significance="preferred"><primary>Rule</primary><secondary>Determine Resource Location</secondary></indexterm> - <indexterm><primary>Resource</primary><secondary>Location, Determine by Rules</secondary></indexterm> - Using Rules to Determine Resource Location - - If the constraint's outer-most rule evaluates to false, the cluster treats the constraint as if it was not there. - When the rule evaluates to true, the node's preference for running the resource is updated with the score associated with the rule. - - - If this sounds familiar, its because you have been using a simplified syntax for location constraint rules already. - Consider the following location constraint: - - - Prevent myApacheRsc from running on c001n03 - <rsc_location id="dont-run-apache-on-c001n03" rsc="myApacheRsc" - score="-INFINITY" node="c001n03"/> - - This constraint can be more verbosely written as: - - Prevent myApacheRsc from running on c001n03 - expanded version - - - - - ]]> - - The advantage of using the expanded form is that one can then add extra clauses to the rule, such as limiting the rule such that it only applies during certain times of the day or days of the week (this is discussed in subsequent sections). - - It also allows us to match on node properties other than its name. - If we rated each machine's CPU power such that the cluster had the following nodes section: - - - A sample nodes section for use with score-attribute - - - - - - - - - - - - ]]> - - then we could prevent resources from running on underpowered machines with the rule - - - ]]> -
- Using <literal>score-attribute</literal> Instead of <literal>score</literal> - - When using score-attribute instead of score, each node matched by the rule has its score adjusted differently, according to its value for the named node attribute. - Thus, in the previous example, if a rule used score-attribute="cpu_mips", c001n01 would have its preference to run the resource increased by 1234 whereas c001n02 would have its preference increased by 5678. - -
-
-
- Using Rules to Control Resource Options - Often some cluster nodes will be different from their peers; sometimes these differences (the location of a binary or the names of network interfaces) require resources to be configured differently depending on the machine they're hosted on. - By defining multiple instance_attributes objects for the resource and adding a rule to each, we can easily handle these special cases. - In the example below, mySpecialRsc will use eth1 and port 9999 when run on node1, eth2 and port 8888 on node2 and default to eth0 and port 9999 for all other nodes. - - Defining different resource options based on the node name - - - - - - - - - - - - - - - - - - - ]]> - - - The order in which instance_attributes objects are evaluated is determined by their score (highest to lowest). - If not supplied, score defaults to zero and objects with an equal score are processed in listed order. - If the instance_attributes object does not have a rule or has a rule that evaluates to true, then for any parameter the resource does not yet have a value for, the resource will use the parameter values defined by the instance_attributes object. - -
-
- - <indexterm><primary>Rule</primary><secondary>Controlling Cluster Options</secondary></indexterm> - <indexterm><primary>Cluster Options</primary><secondary>Controlled by Rules</secondary></indexterm> - Using Rules to Control Cluster Options - Controlling cluster options is achieved in much the same manner as specifying different resource options on different nodes. - - The difference is that because they are cluster options, one cannot (or should not, because they won't work) use attribute based expressions. - The following example illustrates how to set a different resource-stickiness value during and outside of work hours. - This allows resources to automatically move back to their most preferred hosts, but at a time that (in theory) does not interfere with business activities. - - - Change <literal>resource-stickiness</literal> during working hours - - - - - - - - - - - - - ]]> - -
-
- Ensuring Time Based Rules Take Effect - - A Pacemaker cluster is an event driven system. - As such, it won't recalculate the best place for resources to run in unless something (like a resource failure or configuration change) happens. - This can mean that a location constraint that only allows resource X to run between 9am and 5pm is not enforced. - - - If you rely on time based rules, it is essential that you set the cluster-recheck-interval option. - This tells the cluster to periodically recalculate the ideal state of the cluster. - For example, if you set cluster-recheck-interval=5m, then sometime between 9:00 and 9:05 the cluster would notice that it needs to start resource X, and between 17:00 and 17:05 it would realize that X needed to be stopped. - - Note that the timing of the actual start and stop actions depends on what else needs to be performed first. -
- diff --git a/doc/Pacemaker_Explained/en-US/Ch-Status.txt b/doc/Pacemaker_Explained/en-US/Ch-Status.txt new file mode 100644 index 0000000000..44f6b46edf --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ch-Status.txt @@ -0,0 +1,371 @@ += Status - Here be dragons = + +Most users never need to understand the contents of the status section +and can be happy with the output from `crm_mon`. + +However for those with a curious inclination, this section attempts to +provide an overview of its contents. + +== Node Status == + +indexterm:[Node,Status] +indexterm:[Status of a Node] + +In addition to the cluster's configuration, the CIB holds an +up-to-date representation of each cluster node in the status section. + +.A bare-bones status entry for a healthy node called +cl-virt-1+ +[source,XML] +----- + + + + +----- + + + +Users are highly recommended _not to modify_ any part of a node's +state _directly_. The cluster will periodically regenerate the entire +section from authoritative sources. So any changes should be done +with the tools for those subsystems. + +.Authoritative Sources for State Information +[width="95%",cols="5m,5<",options="header",align="center"] +|========================================================= + +|Dataset |Authoritative Source + +|node_state fields |crmd + +|transient_attributes tag |attrd + +|lrm tag |lrmd + +|========================================================= + +The fields used in the +node_state+ objects are named as they are +largely for historical reasons and are rooted in Pacemaker's origins +as the Heartbeat resource manager. + +They have remained unchanged to preserve compatibility with older +versions. + +.Node Status Fields +[width="95%",cols="2m,5<",options="header",align="center"] +|========================================================= + +|Field |Description + + +| id | +indexterm:[id,Node Status Field] +indexterm:[>Node,Status Field,id] +Unique identifier for the node. Corosync based clusters use the uname +of the machine, Heartbeat clusters use a human-readable (but annoying) +UUID. + +| uname | +indexterm:[uname Node Status Field] +indexterm:[>Node,Status Field,uname] +The node's machine name (output from `uname -n`). + +| ha | +indexterm:[ha Node Status Field] +indexterm:[>Node,Status Field,ha] +Flag specifying whether the cluster software is active on the +node. Allowed values: +active+, +dead+. + +| in_ccm | +indexterm:[in_ccm Node Status Field] +indexterm:[>Node,Status Field,in_ccm] +Flag for cluster membership; allowed values: +true+, +false+. + +| crmd | +indexterm:[crmd Node Status Field] +indexterm:[>Node,Status Field,crmd] +Flag: is the crmd process active on the node? One of +online+, +offline+. + +| join | +indexterm:[join Node Status Field] +indexterm:[>Node,Status Field,join] +Flag saying whether the node participates in hosting +resources. Possible values: +down+, +pending+, +member+, +banned+. + +| expected | +indexterm:[expected Node Status Field] +indexterm:[>Node,Status Field,expected] +Expected value for +join+. + +| crm-debug-origin | +indexterm:[crm-debug-origin Node Status Field] +indexterm:[>Node,Status Field,crm-debug-origin] +Diagnostic indicator: the origin of the most recent change(s). + +|========================================================= + +The cluster uses these fields to determine if, at the node level, the +node is healthy or is in a failed state and needs to be fenced. + +== Transient Node Attributes == + +Like regular xref:s-node-attributes[node attributes], the name/value +pairs listed here also help to describe the node. However they are +forgotten by the cluster when the node goes offline. This can be +useful, for instance, when you want a node to be in standby mode (not +able to run resources) until the next reboot. + +In addition to any values the administrator sets, the cluster will +also store information about failed resources here. + +.Example set of transient node attributes for node "cl-virt-1" +[source,XML] +----- + + + + + + + + +----- + +In the above example, we can see that the +pingd:0+ resource has +failed once, at +Mon Apr 6 11:22:22 2009+. +footnote:[ +You can use the standard +date+ command to print a human readable of +any seconds-since-epoch value: + # `date -d @number` +] +We also see that the node is connected to three "pingd" peers and that +all known resources have been checked for on this machine (+probe_complete+). + +== Operation History == +indexterm:[Operation History] + +A node's resource history is held in the +lrm_resources+ tag (a child +of the +lrm+ tag). The information stored here includes enough +information for the cluster to stop the resource safely if it is +removed from the +configuration+ section. Specifically the resource's ++id+, +class+, +type+ and +provider+ are stored. + +.A record of the apcstonith resource +[source,XML] +----- + +----- + +Additionally, we store the last job for every combination of ++resource, action+ and +interval+. The concatenation of the values in +this tuple are used to create the id of the +lrm_rsc_op+ object. + +.Contents of an +lrm_rsc_op+ job +[width="95%",cols="2m,5<",options="header",align="center"] +|========================================================= + +|Field +|Description + +| id | +indexterm:[id,Job Field] +indexterm:[>Job Field,id] + +Identifier for the job constructed from the resource's +id+, ++operation+ and +interval+. + +| call-id | +indexterm:[call-id Job Field] +indexterm:[>Job Field,call-id] + +The job's ticket number. Used as a sort key to determine the order in +which the jobs were executed. + +| operation | +indexterm:[operation Job Field] +indexterm:[>Job Field,operation] + +The action the resource agent was invoked with. + +| interval | +indexterm:[interval Job Field] +indexterm:[>Job Field,interval] + +The frequency, in milliseconds, at which the operation will be +repeated. A one-off job is indicated by 0. + +| op-status | +indexterm:[op-status Job Field] +indexterm:[>Job Field,op-status] + +The job's status. Generally this will be either 0 (done) or -1 +(pending). Rarely used in favor of +rc-code+. + +| rc-code | +indexterm:[rc-code Job Field] +indexterm:[>Job Field,rc-code] + +The job's result. Refer to xref:s-ocf-return-codes[] for +details on what the values here mean and how they are interpreted. + +| last-run | +indexterm:[last-run Job Field] +indexterm:[>Job Field,last-run] + +Diagnostic indicator. Machine local date/time, in seconds since epoch, +at which the job was executed. + +| last-rc-change | +indexterm:[last-rc-change Job Field] +indexterm:[>Job Field,last-rc-change] + +Diagnostic indicator. Machine local date/time, in seconds since epoch, +at which the job first returned the current value of +rc-code+. + +| exec-time | +indexterm:[exec-time Job Field] +indexterm:[>Job Field,exec-time] + +Diagnostic indicator. Time, in milliseconds, that the job was running for. + +| queue-time | +indexterm:[queue-time Job Field] +indexterm:[>Job Field,queue-time] + +Diagnostic indicator. Time, in seconds, that the job was queued for in the LRMd. + +| crm_feature_set | +indexterm:[crm_feature_set Job Field] +indexterm:[>Job Field,crm_feature_set] + +The version which this job description conforms to. Used when +processing +op-digest+. + +| transition-key | +indexterm:[transition-key Job Field] +indexterm:[>Job Field,transition-key] + +A concatenation of the job's graph action number, the graph number, +the expected result and the UUID of the crmd instance that scheduled +it. This is used to construct +transition-magic+ (below). + +| transition-magic | +indexterm:[transition-magic Job Field] +indexterm:[>Job Field,transition-magic] + +A concatenation of the job's +op-status+, +rc-code+ and ++transition-key+. Guaranteed to be unique for the life of the cluster +(which ensures it is part of CIB update notifications) and contains +all the information needed for the crmd to correctly analyze and +process the completed job. Most importantly, the decomposed elements +tell the crmd if the job entry was expected and whether it failed. + +| op-digest | +indexterm:[op-digest Job Field] +indexterm:[>Job Field,op-digest] + +An MD5 sum representing the parameters passed to the job. Used to +detect changes to the configuration, to restart resources if +necessary. + +| crm-debug-origin | +indexterm:[crm-debug-origin Job Field] +indexterm:[>Job Field,crm-debug-origin] + +Diagnostic indicator. The origin of the current values. + +|========================================================= + +=== Simple Example === + +.A monitor operation (determines current state of the apcstonith resource) +[source,XML] +----- + + + +----- + +In the above example, the job is a non-recurring monitor operation +often referred to as a "probe" for the +apcstonith+ resource. + +The cluster schedules probes for every configured resource on when a +new node starts, in order to determine the resource's current state +before it takes any further action. + +From the +transition-key+, we can see that this was the 22nd action of +the 2nd graph produced by this instance of the crmd +(2668bbeb-06d5-40f9-936d-24cb7f87006a). + +The third field of the +transition-key+ contains a 7, this indicates +that the job expects to find the resource inactive. + +By looking at the +rc-code+ property, we see that this was the case. + + +As that is the only job recorded for this node we can conclude that +the cluster started the resource elsewhere. + +=== Complex Resource History Example === + +.Resource history of a pingd clone with multiple jobs +[source,XML] +----- + + + + + + +----- + +When more than one job record exists, it is important to first sort +them by +call-id+ before interpreting them. + +Once sorted, the above example can be summarized as: + +. A non-recurring monitor operation returning 7 (not running), with a +call-id+ of 3 +. A stop operation returning 0 (success), with a +call-id+ of 32 +. A start operation returning 0 (success), with a +call-id+ of 33 +. A recurring monitor returning 0 (success), with a +call-id+ of 34 + + +The cluster processes each job record to build up a picture of the +resource's state. After the first and second entries, it is +considered stopped and after the third it considered active. + +Based on the last operation, we can tell that the resource is +currently active. + +Additionally, from the presence of a +stop+ operation with a lower ++call-id+ than that of the +start+ operation, we can conclude that the +resource has been restarted. Specifically this occurred as part of +actions 11 and 31 of transition 11 from the crmd instance with the key ++2668bbeb...+. This information can be helpful for locating the +relevant section of the logs when looking for the source of a failure. diff --git a/doc/Pacemaker_Explained/en-US/Ch-Status.xml b/doc/Pacemaker_Explained/en-US/Ch-Status.xml deleted file mode 100644 index 682862f9a1..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ch-Status.xml +++ /dev/null @@ -1,335 +0,0 @@ - - Status - Here be dragons - - Most users never need to understand the contents of the status section and can be happy with the output from crm_mon. - However for those with a curious inclination, this section attempts to provide an overview of its contents. - -
- <indexterm significance="preferred"><primary>Node</primary><secondary>Status</secondary></indexterm> - <indexterm significance="preferred"><primary>Status of a Node</primary></indexterm> - Node Status - In addition to the cluster's configuration, the CIB holds an up-to-date representation of each cluster node in the status section. -
- A bare-bones status entry for a healthy node called <literal>cl-virt-1</literal> - - - - ]]> -
- - Users are highly recommended not to modify any part of a node's state directly. - The cluster will periodically regenerate the entire section from authoritative sources. - So any changes should be done with the tools for those subsystems. - - - Authoritative Sources for State Information - - - - Dataset - Authoritative Source - - - node_state fields - crmd - - - transient_attributes tag - attrd - - - lrm tag - lrmd - -
- - The fields used in the node_state objects are named as they are largely for historical reasons and are rooted in Pacemaker's origins as the Heartbeat resource manager. - They have remained unchanged to preserve compatibility with older versions. - - - Node Status Fields - - - - - - Field - Description - - - idNode Status Field - NodeStatus Fieldid - id - Unique identifier for the node. Corosync based clusters use the uname of the machine, Heartbeat clusters use a human-readable (but annoying) UUID. - - - uname Node Status Field - NodeStatus Fielduname - uname - The node's machine name (output from uname -n). - - - ha Node Status Field - NodeStatus Fieldha - ha - Flag specifying whether the cluster software is active on the node. Allowed values: active, dead. - - - in_ccm Node Status Field - NodeStatus Fieldin_ccm - in_ccm - Flag for cluster membership; allowed values: true, false. - - - crmd Node Status Field - NodeStatus Fieldcrmd - crmd - Flag: is the crmd process active on the node? One of online, offline. - - - join Node Status Field - NodeStatus Fieldjoin - join - Flag saying whether the node participates in hosting resources. Possible values: down, pending, member, banned. - - - expected Node Status Field - NodeStatus Fieldexpected - expected - Expected value for join. - - - crm-debug-origin Node Status Field - NodeStatus Fieldcrm-debug-origin - crm-debug-origin - Diagnostic indicator: the origin of the most recent change(s). - -
- The cluster uses these fields to determine if, at the node level, the node is healthy or is in a failed state and needs to be fenced. -
-
- Transient Node Attributes - - Like regular node attributes, the name/value pairs listed here also help to describe the node. - However they are forgotten by the cluster when the node goes offline. - This can be useful, for instance, when you want a node to be in standby mode (not able to run resources) until the next reboot. - - In addition to any values the administrator sets, the cluster will also store information about failed resources here. -
- Example set of transient node attributes for node "cl-virt-1" - - - - - - - - ]]> -
- In the above example, we can see that the pingd:0 resource has failed once, at Mon Apr 6 11:22:22 2009 - You can use the standard date command to print a human readable of any seconds-since-epoch value: - # date -d @number - . - We also see that the node is connected to three "pingd" peers and that all known resources have been checked for on this machine (probe_complete). - -
-
- <indexterm significance="preferred"><primary>Operation History</primary></indexterm> - Operation History - - A node's resource history is held in the lrm_resources tag (a child of the lrm tag). - The information stored here includes enough information for the cluster to stop the resource safely if it is removed from the configuration section. - Specifically the resource's id, class, type and provider are stored. - -
- A record of the apcstonith resource - <lrm_resource id="apcstonith" type="apcmastersnmp" class="stonith"> - -
- - Additionally, we store the last job for every combination of resource, action and interval. - The concatenation of the values in this tuple are used to create the id of the lrm_rsc_op object. - - - Contents of an <literal>lrm_rsc_op</literal> job. - - - - - - Field - Description - - - idJob Field - Job Fieldid - id - Identifier for the job constructed from the resource's id, operation and interval. - - - call-id Job Field - Job Fieldcall-id - call-id - The job's ticket number. Used as a sort key to determine the order in which the jobs were executed. - - - operation Job Field - Job Fieldoperation - operation - The action the resource agent was invoked with. - - - interval Job Field - Job Fieldinterval - interval - The frequency, in milliseconds, at which the operation will be repeated. A one-off job is indicated by 0. - - - op-status Job Field - Job Fieldop-status - op-status - The job's status. Generally this will be either 0 (done) or -1 (pending). Rarely used in favor of rc-code. - - - rc-code Job Field - Job Fieldrc-code - rc-code - The job's result. Refer to for details on what the values here mean and how they are interpreted. - - - last-run Job Field - Job Fieldlast-run - last-run - Diagnostic indicator. Machine local date/time, in seconds since epoch, at which the job was executed. - - - last-rc-change Job Field - Job Fieldlast-rc-change - last-rc-change - Diagnostic indicator. Machine local date/time, in seconds since epoch, at which the job first returned the current value of rc-code. - - - exec-time Job Field - Job Fieldexec-time - exec-time - Diagnostic indicator. Time, in milliseconds, that the job was running for. - - - queue-time Job Field - Job Fieldqueue-time - queue-time - Diagnostic indicator. Time, in seconds, that the job was queued for in the LRMd. - - - crm_feature_set Job Field - Job Fieldcrm_feature_set - crm_feature_set - The version which this job description conforms to. Used when processing op-digest. - - - transition-key Job Field - Job Fieldtransition-key - transition-key - A concatenation of the job's graph action number, the graph number, the expected result and the UUID of the crmd instance that scheduled it. This is used to construct transition-magic (below). - - - transition-magic Job Field - Job Fieldtransition-magic - transition-magic - A concatenation of the job's op-status, rc-code and transition-key. Guaranteed to be unique for the life of the cluster (which ensures it is part of CIB update notifications) and contains all the information needed for the crmd to correctly analyze and process the completed job. Most importantly, the decomposed elements tell the crmd if the job entry was expected and whether it failed. - - - op-digest Job Field - Job Fieldop-digest - op-digest - An MD5 sum representing the parameters passed to the job. Used to detect changes to the configuration, to restart resources if necessary. - - - crm-debug-origin Job Field - Job Fieldcrm-debug-origin - crm-debug-origin - Diagnostic indicator. The origin of the current values. - - - -
-
- Simple Example -
- A monitor operation (determines current state of the apcstonith resource) - - - ]]> -
- - In the above example, the job is a non-recurring monitor operation often referred to as a "probe" for the apcstonith resource. - The cluster schedules probes for every configured resource on when a new node starts, in order to determine the resource's current state before it takes any further action. - - - From the transition-key, we can see that this was the 22nd action of the 2nd graph produced by this instance of the crmd (2668bbeb-06d5-40f9-936d-24cb7f87006a). - The third field of the transition-key contains a 7, this indicates that the job expects to find the resource inactive. - By looking at the rc-code property, we see that this was the case. - - As that is the only job recorded for this node we can conclude that the cluster started the resource elsewhere. -
-
- Complex Resource History Example -
- Resource history of a pingd clone with multiple jobs - - - - - - ]]> -
- - When more than one job record exists, it is important to first sort them by call-id before interpreting them. - Once sorted, the above example can be summarized as: - - A non-recurring monitor operation returning 7 (not running), with a call-id of 3 - A stop operation returning 0 (success), with a call-id of 32 - A start operation returning 0 (success), with a call-id of 33 - A recurring monitor returning 0 (success), with a call-id of 34 - - - - The cluster processes each job record to build up a picture of the resource's state. - After the first and second entries, it is considered stopped and after the third it considered active. - Based on the last operation, we can tell that the resource is currently active. - - - Additionally, from the presence of a stop operation with a lower call-id than that of the start operation, we can conclude that the resource has been restarted. - Specifically this occurred as part of actions 11 and 31 of transition 11 from the crmd instance with the key 2668bbeb.... - This information can be helpful for locating the relevant section of the logs when looking for the source of a failure. - -
-
- diff --git a/doc/Pacemaker_Explained/en-US/Ch-Stonith.txt b/doc/Pacemaker_Explained/en-US/Ch-Stonith.txt new file mode 100644 index 0000000000..f7a30a0c0f --- /dev/null +++ b/doc/Pacemaker_Explained/en-US/Ch-Stonith.txt @@ -0,0 +1,307 @@ += Configure STONITH = + +== What Is STONITH == + +anchor:ch-stonith[Configuring STONITH] + +STONITH is an acronym for Shoot-The-Other-Node-In-The-Head and it +protects your data from being corrupted by rogue nodes or concurrent +access. + +Just because a node is unresponsive, this doesn't mean it isn't +accessing your data. The only way to be 100% sure that your data is +safe, is to use STONITH so we can be certain that the node is truly +offline, before allowing the data to be accessed from another node. + + +STONITH also has a role to play in the event that a clustered service +cannot be stopped. In this case, the cluster uses STONITH to force the +whole node offline, thereby making it safe to start the service +elsewhere. + +== What STONITH Device Should You Use == + +It is crucial that the STONITH device can allow the cluster to +differentiate between a node failure and a network one. + +The biggest mistake people make in choosing a STONITH device is to +use remote power switch (such as many on-board IMPI controllers) that +shares power with the node it controls. In such cases, the cluster +cannot be sure if the node is really offline, or active and suffering +from a network fault. + +Likewise, any device that relies on the machine being active (such as +SSH-based "devices" used during testing) are inappropriate. + +== Configuring STONITH == + +ifdef::pcs[] +. Find the correct driver: +pcs stonith list+ + +. Find the parameters associated with the device: +pcs stonith describe + + +. Create a local config to make changes to +pcs cluster cib stonith_cfg+ + +. Create the fencing resource using +pcs -f stonith_cfg stonith create + [stonith device options]+ + +. Set stonith-enable to true. +pcs -f stonith_cfg property set stonith-enabled=true+ +endif::[] + +ifdef::crm[] +. Find the correct driver: +stonith_admin --list-installed+ + +. Since every device is different, the parameters needed to configure + it will vary. To find out the parameters associated with the device, + run: +stonith_admin --metadata --agent type+ + + The output should be XML formatted text containing additional + parameter descriptions. We will endevor to make the output more + friendly in a later version. + +. Enter the shell crm Create an editable copy of the existing + configuration +cib new stonith+ Create a fencing resource containing a + primitive resource with a class of stonith, a type of type and a + parameter for each of the values returned in step 2: +configure + primitive ...+ +endif::[] + +. If the device does not know how to fence nodes based on their uname, + you may also need to set the special +pcmk_host_map+ parameter. See + +man stonithd+ for details. + +. If the device does not support the list command, you may also need + to set the special +pcmk_host_list+ and/or +pcmk_host_check+ + parameters. See +man stonithd+ for details. + +. If the device does not expect the victim to be specified with the + port parameter, you may also need to set the special + +pcmk_host_argument+ parameter. See +man stonithd+ for details. + +ifdef::crm[] +. Upload it into the CIB from the shell: +cib commit stonith+ +endif::[] + +ifdef::pcs[] +. Commit the new configuration. +pcs cluster push cib stonith_cfg+ +endif::[] + +. Once the stonith resource is running, you can test it by executing: + +stonith_admin --reboot nodename+. Although you might want to stop the + cluster on that machine first. + +== Example == + +Assuming we have an chassis containing four nodes and an IPMI device +active on 10.0.0.1, then we would chose the fence_ipmilan driver in step +2 and obtain the following list of parameters + +.Obtaining a list of STONITH Parameters + +ifdef::pcs[] +[source,Bash] +---- +# pcs stonith describe fence_ipmilan +Stonith options for: fence_ipmilan + auth: IPMI Lan Auth type (md5, password, or none) + ipaddr: IPMI Lan IP to talk to + passwd: Password (if required) to control power on IPMI device + passwd_script: Script to retrieve password (if required) + lanplus: Use Lanplus + login: Username/Login (if required) to control power on IPMI device + action: Operation to perform. Valid operations: on, off, reboot, status, list, diag, monitor or metadata + timeout: Timeout (sec) for IPMI operation + cipher: Ciphersuite to use (same as ipmitool -C parameter) + method: Method to fence (onoff or cycle) + power_wait: Wait X seconds after on/off operation + delay: Wait X seconds before fencing is started + privlvl: Privilege level on IPMI device + verbose: Verbose mode +---- +endif::[] + +ifdef::crm[] +[source,Bash] +---- +# stonith_admin --metadata -a fence_ipmilan +---- +[source,XML] +---- + + + +fence_ipmilan is an I/O Fencing agent which can be used with machines controlled by IPMI. This agent calls support software using ipmitool (http://ipmitool.sf.net/). + +To use fence_ipmilan with HP iLO 3 you have to enable lanplus option (lanplus / -P) and increase wait after operation to 4 seconds (power_wait=4 / -T 4) + + + + + IPMI Lan Auth type (md5, password, or none) + + + + + IPMI Lan IP to talk to + + + + + Password (if required) to control power on IPMI device + + + + + Script to retrieve password (if required) + + + + + Use Lanplus + + + + + Username/Login (if required) to control power on IPMI device + + + + + Operation to perform. Valid operations: on, off, reboot, status, list, diag, monitor or metadata + + + + + Timeout (sec) for IPMI operation + + + + + Ciphersuite to use (same as ipmitool -C parameter) + + + + + Method to fence (onoff or cycle) + + + + + Wait X seconds after on/off operation + + + + + Wait X seconds before fencing is started + + + + + Verbose mode + + + + + + + + + + + + + +---- +endif::[] + +from which we would create a STONITH resource fragment that might look +like this + +.Sample STONITH Resource +ifdef::pcs[] +[source,Bash] +---- +# pcs cluster cib stonith_cfg +# pcs -f stonith_cfg stonith create impi-fencing fence_ipmilan \ + pcmk_host_list="pcmk-1 pcmk-2" ipaddr=10.0.0.1 login=testuser \ + passwd=acd123 op monitor interval=60s +# pcs -f stonith_cfg stonith + impi-fencing (stonith:fence_ipmilan) Stopped +---- +endif::[] + +ifdef::crm[] +[source,Bash] +---- +# crm crm(live)# cib new stonith +INFO: stonith shadow CIB created +crm(stonith)# configure primitive impi-fencing stonith::fence_ipmilan \ + params pcmk_host_list="pcmk-1 pcmk-2" ipaddr=10.0.0.1 login=testuser passwd=abc123 \ + op monitor interval="60s" +---- +endif::[] + +And finally, since we disabled it earlier, we need to re-enable STONITH. +At this point we should have the following configuration. + +ifdef::pcs[] +[source,Bash] +---- +# pcs -f stonith_cfg property set stonith-enabled=true +# pcs -f stonith_cfg property +dc-version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 +cluster-infrastructure: corosync +no-quorum-policy: ignore +stonith-enabled: true +---- + +Now push the configuration into the cluster. + +ifdef::pcs[] +[source,Bash] +---- +# pcs cluster push cib stonith_cfg +---- +endif::[] + +ifdef::crm[] +[source,Bash] +---- +crm(stonith)# configure property stonith-enabled="true" +crm(stonith)# configure shownode pcmk-1 +node pcmk-2 +primitive WebData ocf:linbit:drbd \ + params drbd_resource="wwwdata" \ + op monitor interval="60s" +primitive WebFS ocf:heartbeat:Filesystem \ + params device="/dev/drbd/by-res/wwwdata" directory="/var/www/html" fstype="gfs2" +primitive WebSite ocf:heartbeat:apache \ + params configfile="/etc/httpd/conf/httpd.conf" \ + op monitor interval="1min" +primitive ClusterIP ocf:heartbeat:IPaddr2 \ + params ip="192.168.122.101" cidr_netmask="32" clusterip_hash="sourceip" \ + op monitor interval="30s"primitive ipmi-fencing stonith::fence_ipmilan \ params pcmk_host_list="pcmk-1 pcmk-2" ipaddr=10.0.0.1 login=testuser passwd=abc123 \ op monitor interval="60s"ms WebDataClone WebData \ + meta master-max="2" master-node-max="1" clone-max="2" clone-node-max="1" notify="true" +clone WebFSClone WebFS +clone WebIP ClusterIP \ + meta globally-unique="true" clone-max="2" clone-node-max="2" +clone WebSiteClone WebSite +colocation WebSite-with-WebFS inf: WebSiteClone WebFSClone +colocation fs_on_drbd inf: WebFSClone WebDataClone:Master +colocation website-with-ip inf: WebSiteClone WebIP +order WebFS-after-WebData inf: WebDataClone:promote WebFSClone:start +order WebSite-after-WebFS inf: WebFSClone WebSiteClone +order apache-after-ip inf: WebIP WebSiteClone +property $id="cib-bootstrap-options" \ + dc-version="1.1.5-bdd89e69ba545404d02445be1f3d72e6a203ba2f" \ + cluster-infrastructure="openais" \ + expected-quorum-votes="2" \ + stonith-enabled="true" \ + no-quorum-policy="ignore" +rsc_defaults $id="rsc-options" \ + resource-stickiness="100" +crm(stonith)# cib commit stonithINFO: commited 'stonith' shadow CIB to the cluster +crm(stonith)# quit +bye +---- +endif::[] diff --git a/doc/Pacemaker_Explained/en-US/Ch-Stonith.xml b/doc/Pacemaker_Explained/en-US/Ch-Stonith.xml deleted file mode 100644 index 1ffa5575d2..0000000000 --- a/doc/Pacemaker_Explained/en-US/Ch-Stonith.xml +++ /dev/null @@ -1,155 +0,0 @@ - - Protecting Your Data - STONITH -
- Why You Need STONITH - STONITH is an acronym for Shoot-The-Other-Node-In-The-Head; its purpose is to protect your data from being corrupted by rogue nodes or concurrent access. - - When a node is unresponsive it might still access your data. - The only way to be 100% sure that your data is safe, is to use STONITH, so we can be certain that the node is truly offline, before allowing the data to be accessed from another node. - - - STONITH also has a role to play in the event that a clustered service cannot be stopped. - In this case, the cluster uses STONITH to force the whole node offline, thereby making it safe to start the service elsewhere. - -
-
- What STONITH Device Should You Use - It is crucial that the STONITH device can allow the cluster to differentiate between a node and a network failure. - - The biggest mistake people make in choosing a STONITH device is to use a remote power switch (such as many on-board IPMI controllers) that shares power with the node it controls. - In such cases, the cluster cannot be sure if the node is really offline, or active and suffering from a network fault. - - Likewise, any device that relies on the machine being active (such as SSH-based "devices" used during testing) are inappropriate. -
-
- Configuring STONITH - - - Find the correct driver: stonith_admin --list-installed - - - Since every device is different, the parameters needed to configure it will vary. - To find out which parameters the device supports resp. needs, run: - stonith_admin --metadata --agent type - - The output should be XML formatted text containing additional parameter descriptions. We - will endeavour to make the output more friendly in a later version. - - - Create a file called stonith.xml containing a primitive resource with a class of - stonith, a type of type and a parameter for each of the values - returned in step 2. - - - If the device does not know how to fence nodes based on their uname, you may also need - to set the special pcmk_host_map parameter. See man - stonithd for details. - - - If the device does not support the list command, you may also - need to set the special pcmk_host_list and/or - pcmk_host_check parameters. See man stonithd - for details. - - - If the device does not expect the victim to be specified with the - port parameter, you may also need to set the special - pcmk_host_argument parameter. See man stonithd - for details. - - - Upload it into the CIB using cibadmin: cibadmin -C -o resources --xml-file - stonith.xml - - - Once the stonith resource is running, you can test it by executing: - stonith_admin --reboot nodename. Although - you might want to stop the cluster on that machine first. - - -
- Example - Assuming we have an chassis containing four nodes and an IPMI device active on 10.0.0.1, then - we would chose the fence_ipmilan driver in step 2 and obtain the - following list of parameters: -
- Obtaining a list of STONITH Parameters - # stonith_admin --metadata -a fence_ipmilan - - -fence_ipmilan is an I/O Fencing agent which can be used with machines controlled by IPMI. -This agent calls support software using ipmitool (http://ipmitool.sf.net/). - -To use fence_ipmilan with HP iLO 3 you have to enable lanplus option (lanplus / -P) and -increase wait after operation to 4 seconds (power_wait=4 / -T 4) - - - IPMI Lan Auth type (md5, password, or none) - - - IPMI Lan IP to talk to - - - Password to control power on IPMI device - - - Script to retrieve password (if required) - - - Use Lanplus - - - Username/Login to control IPMI device - - - Operation to perform. Valid operations: - on, off, reboot, status, list, diag, monitor or metadata - - - Timeout (sec) for IPMI operation - - - Ciphersuite to use (same as ipmitool -C parameter) - - - Method to fence (onoff or cycle) - - - Wait X seconds after on/off operation - - - Wait X seconds before fencing is started - - - Verbose mode - - - - - - - - - -]]> -
- From this list we would create a STONITH resource fragment that might look like this: - - Sample STONITH Resource - - - - - - - - - - - ]]> - - The monitor interval of two hours is explained by bugs in some IPMI implementations; see Monitoring the fencing devices. -
-
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