diff --git a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Resources.txt b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Resources.txt index 46a291ba8b..c89315885a 100644 --- a/doc/Pacemaker_Explained/en-US/Ch-Advanced-Resources.txt +++ b/doc/Pacemaker_Explained/en-US/Ch-Advanced-Resources.txt @@ -1,1522 +1,1517 @@ = Advanced Resource Types = [[group-resources]] == Groups - A Syntactic Shortcut == indexterm:[Group Resources] indexterm:[Resource,Groups] One of the most common elements of a cluster is a set of resources that need to be located together, start sequentially, and stop in the reverse order. To simplify this configuration, we support the concept of groups. .A group of two primitive resources ====== [source,XML] ------- ------- ====== Although the example above contains only two resources, there is no limit to the number of resources a group can contain. The example is also sufficient to explain the fundamental properties of a group: * Resources are started in the order they appear in (+Public-IP+ first, then +Email+) * Resources are stopped in the reverse order to which they appear in (+Email+ first, then +Public-IP+) If a resource in the group can't run anywhere, then nothing after that is allowed to run, too. * If +Public-IP+ can't run anywhere, neither can +Email+; * but if +Email+ can't run anywhere, this does not affect +Public-IP+ in any way The group above is logically equivalent to writing: .How the cluster sees a group resource ====== [source,XML] ------- ------- ====== Obviously as the group grows bigger, the reduced configuration effort can become significant. Another (typical) example of a group is a DRBD volume, the filesystem mount, an IP address, and an application that uses them. === Group Properties === .Properties of a Group Resource [width="95%",cols="3m,5<",options="header",align="center"] |========================================================= |Field |Description |id |A unique name for the group indexterm:[id,Group Resource Property] indexterm:[Resource,Group Property,id] |========================================================= === Group Options === Groups inherit the +priority+, +target-role+, and +is-managed+ properties from primitive resources. See <> for information about those properties. === Group Instance Attributes === Groups have no instance attributes. However, any that are set for the group object will be inherited by the group's children. === Group Contents === Groups may only contain a collection of cluster resources (see <>). To refer to a child of a group resource, just use the child's +id+ instead of the group's. === Group Constraints === Although it is possible to reference a group's children in constraints, it is usually preferable to reference the group itself. .Some constraints involving groups ====== [source,XML] ------- ------- ====== === Group Stickiness === indexterm:[resource-stickiness,Groups] Stickiness, the measure of how much a resource wants to stay where it is, is additive in groups. Every active resource of the group will contribute its stickiness value to the group's total. So if the default +resource-stickiness+ is 100, and a group has seven members, five of which are active, then the group as a whole will prefer its current location with a score of 500. [[s-resource-clone]] == Clones - Resources That Get Active on Multiple Hosts == indexterm:[Clone Resources] indexterm:[Resource,Clones] Clones were initially conceived as a convenient way to start multiple instances of an IP address resource and have them distributed throughout the cluster for load balancing. They have turned out to quite useful for a number of purposes including integrating with the Distributed Lock Manager (used by many cluster filesystems), the fencing subsystem, and OCFS2. You can clone any resource, provided the resource agent supports it. Three types of cloned resources exist: * Anonymous * Globally unique * Stateful 'Anonymous' clones are the simplest. These behave completely identically everywhere they are running. Because of this, there can be only one copy of an anonymous clone active per machine. 'Globally unique' clones are distinct entities. A copy of the clone running on one machine is not equivalent to another instance on another node, nor would any two copies on the same node be equivalent. 'Stateful' clones are covered later in <>. .A clone of an LSB resource ====== [source,XML] ------- ------- ====== === Clone Properties === .Properties of a Clone Resource [width="95%",cols="3m,5<",options="header",align="center"] |========================================================= |Field |Description |id |A unique name for the clone indexterm:[id,Clone Property] indexterm:[Clone,Property,id] |========================================================= === Clone Options === Options inherited from <> resources: +priority, target-role, is-managed+ .Clone-specific configuration options [width="95%",cols="1m,1,3<",options="header",align="center"] |========================================================= |Field |Default |Description |clone-max |number of nodes in cluster |How many copies of the resource to start indexterm:[clone-max,Clone Option] indexterm:[Clone,Option,clone-max] |clone-node-max |1 |How many copies of the resource can be started on a single node indexterm:[clone-node-max,Clone Option] indexterm:[Clone,Option,clone-node-max] |clone-min |1 |Require at least this number of clone instances to be runnable before allowing resources depending on the clone to be runnable '(since 1.1.14)' indexterm:[clone-min,Clone Option] indexterm:[Clone,Option,clone-min] |notify |true |When stopping or starting a copy of the clone, tell all the other copies beforehand and again when the action was successful. Allowed values: +false+, +true+ indexterm:[notify,Clone Option] indexterm:[Clone,Option,notify] |globally-unique |false |Does each copy of the clone perform a different function? Allowed values: +false+, +true+ indexterm:[globally-unique,Clone Option] indexterm:[Clone,Option,globally-unique] |ordered |false |Should the copies be started in series (instead of in parallel)? Allowed values: +false+, +true+ indexterm:[ordered,Clone Option] indexterm:[Clone,Option,ordered] |interleave |false |If this clone depends on another clone via an ordering constraint, is it allowed to start after the local instance of the other clone starts, rather than wait for all instances of the other clone to start? Allowed values: +false+, +true+ indexterm:[interleave,Clone Option] indexterm:[Clone,Option,interleave] |========================================================= === Clone Instance Attributes === Clones have no instance attributes; however, any that are set here will be inherited by the clone's children. === Clone Contents === Clones must contain exactly one primitive or group resource. [WARNING] You should never reference the name of a clone's child. If you think you need to do this, you probably need to re-evaluate your design. === Clone Constraints === In most cases, a clone will have a single copy on each active cluster node. If this is not the case, you can indicate which nodes the cluster should preferentially assign copies to with resource location constraints. These constraints are written no differently from those for primitive resources except that the clone's +id+ is used. .Some constraints involving clones ====== [source,XML] ------- ------- ====== Ordering constraints behave slightly differently for clones. In the example above, +apache-stats+ will wait until all copies of +apache-clone+ that need to be started have done so before being started itself. Only if _no_ copies can be started will +apache-stats+ be prevented from being active. Additionally, the clone will wait for +apache-stats+ to be stopped before stopping itself. Colocation of a primitive or group resource with a clone means that the resource can run on any machine with an active copy of the clone. The cluster will choose a copy based on where the clone is running and the resource's own location preferences. Colocation between clones is also possible. If one clone +A+ is colocated with another clone +B+, the set of allowed locations for +A+ is limited to nodes on which +B+ is (or will be) active. Placement is then performed normally. [[s-clone-stickiness]] === Clone Stickiness === indexterm:[resource-stickiness,Clones] To achieve a stable allocation pattern, clones are slightly sticky by default. If no value for +resource-stickiness+ is provided, the clone will use a value of 1. Being a small value, it causes minimal disturbance to the score calculations of other resources but is enough to prevent Pacemaker from needlessly moving copies around the cluster. [NOTE] ==== For globally unique clones, this may result in multiple instances of the clone staying on a single node, even after another eligible node becomes active (for example, after being put into standby mode then made active again). If you do not want this behavior, specify a +resource-stickiness+ of 0 for the clone temporarily and let the cluster adjust, then set it back to 1 if you want the default behavior to apply again. ==== === Clone Resource Agent Requirements === Any resource can be used as an anonymous clone, as it requires no additional support from the resource agent. Whether it makes sense to do so depends on your resource and its resource agent. Globally unique clones do require some additional support in the resource agent. In particular, it must only respond with +$\{OCF_SUCCESS}+ if the node has that exact instance active. All other probes for instances of the clone should result in +$\{OCF_NOT_RUNNING}+ (or one of the other OCF error codes if they are failed). Individual instances of a clone are identified by appending a colon and a numerical offset, e.g. +apache:2+. Resource agents can find out how many copies there are by examining the +OCF_RESKEY_CRM_meta_clone_max+ environment variable and which copy it is by examining +OCF_RESKEY_CRM_meta_clone+. The resource agent must not make any assumptions (based on +OCF_RESKEY_CRM_meta_clone+) about which numerical instances are active. In particular, the list of active copies will not always be an unbroken sequence, nor always start at 0. ==== Clone Notifications ==== Supporting notifications requires the +notify+ action to be implemented. If supported, the notify action will be passed a number of extra variables which, when combined with additional context, can be used to calculate the current state of the cluster and what is about to happen to it. .Environment variables supplied with Clone notify actions [width="95%",cols="5,3<",options="header",align="center"] |========================================================= |Variable |Description |OCF_RESKEY_CRM_meta_notify_type |Allowed values: +pre+, +post+ indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,type] indexterm:[type,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_operation |Allowed values: +start+, +stop+ indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,operation] indexterm:[operation,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_start_resource |Resources to be started indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,start_resource] indexterm:[start_resource,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_stop_resource |Resources to be stopped indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,stop_resource] indexterm:[stop_resource,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_active_resource |Resources that are running indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,active_resource] indexterm:[active_resource,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_inactive_resource |Resources that are not running indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,inactive_resource] indexterm:[inactive_resource,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_start_uname |Nodes on which resources will be started indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,start_uname] indexterm:[start_uname,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_stop_uname |Nodes on which resources will be stopped indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,stop_uname] indexterm:[stop_uname,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_active_uname |Nodes on which resources are running indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,active_uname] indexterm:[active_uname,Notification Environment Variable] |========================================================= The variables come in pairs, such as +OCF_RESKEY_CRM_meta_notify_start_resource+ and +OCF_RESKEY_CRM_meta_notify_start_uname+ and should be treated as an array of whitespace-separated elements. +OCF_RESKEY_CRM_meta_notify_inactive_resource+ is an exception as the matching +uname+ variable does not exist since inactive resources are not running on any node. Thus in order to indicate that +clone:0+ will be started on +sles-1+, +clone:2+ will be started on +sles-3+, and +clone:3+ will be started on +sles-2+, the cluster would set .Notification variables ====== [source,Bash] ------- OCF_RESKEY_CRM_meta_notify_start_resource="clone:0 clone:2 clone:3" OCF_RESKEY_CRM_meta_notify_start_uname="sles-1 sles-3 sles-2" ------- ====== ==== Proper Interpretation of Notification Environment Variables ==== .Pre-notification (stop): * Active resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+ * Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+ * Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ .Post-notification (stop) / Pre-notification (start): * Active resources ** +$OCF_RESKEY_CRM_meta_notify_active_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * Inactive resources ** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ .Post-notification (start): * Active resources: ** +$OCF_RESKEY_CRM_meta_notify_active_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Inactive resources: ** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ [[s-resource-multistate]] == Multi-state - Resources That Have Multiple Modes == indexterm:[Multi-state Resources] indexterm:[Resource,Multi-state] Multi-state resources are a specialization of clone resources; please ensure you understand <> before continuing! Multi-state resources allow the instances to be in one of two operating modes (called 'roles'). The roles are called 'master' and 'slave', but can mean whatever you wish them to mean. The only limitation is that when an instance is started, it must come up in the slave role. === Multi-state Properties === .Properties of a Multi-State Resource [width="95%",cols="3m,5<",options="header",align="center"] |========================================================= |Field |Description |id |Your name for the multi-state resource indexterm:[id,Multi-State Property] indexterm:[Multi-State,Property,id] |========================================================= === Multi-state Options === Options inherited from <> resources: +priority+, +target-role+, +is-managed+ Options inherited from <> resources: +clone-max+, +clone-node-max+, +notify+, +globally-unique+, +ordered+, +interleave+ .Multi-state-specific resource configuration options [width="95%",cols="1m,1,3<",options="header",align="center"] |========================================================= |Field |Default |Description |master-max |1 |How many copies of the resource can be promoted to the +master+ role indexterm:[master-max,Multi-State Option] indexterm:[Multi-State,Option,master-max] |master-node-max |1 |How many copies of the resource can be promoted to the +master+ role on a single node indexterm:[master-node-max,Multi-State Option] indexterm:[Multi-State,Option,master-node-max] |========================================================= === Multi-state Instance Attributes === Multi-state resources have no instance attributes; however, any that are set here will be inherited by a master's children. === Multi-state Contents === Masters must contain exactly one primitive or group resource. [WARNING] You should never reference the name of a master's child. If you think you need to do this, you probably need to re-evaluate your design. === Monitoring Multi-State Resources === The usual monitor actions are insufficient to monitor a multi-state resource, because pacemaker needs to verify not only that the resource is active, but also that its actual role matches its intended one. Define two monitoring actions: the usual one will cover the slave role, and an additional one with +role="master"+ will cover the master role. .Monitoring both states of a multi-state resource ====== [source,XML] ------- ------- ====== [IMPORTANT] =========== It is crucial that _every_ monitor operation has a different interval! Pacemaker currently differentiates between operations only by resource and interval; so if (for example) a master/slave resource had the same monitor interval for both roles, Pacemaker would ignore the role when checking the status -- which would cause unexpected return codes, and therefore unnecessary complications. =========== === Multi-state Constraints === In most cases, multi-state resources will have a single copy on each active cluster node. If this is not the case, you can indicate which nodes the cluster should preferentially assign copies to with resource location constraints. These constraints are written no differently from those for primitive resources except that the master's +id+ is used. When considering multi-state resources in constraints, for most purposes it is sufficient to treat them as clones. The exception is that the +first-action+ and/or +then-action+ fields for ordering constraints may be set to +promote+ or +demote+ to constrain the master role, and colocation constraints may contain +rsc-role+ and/or +with-rsc-role+ fields. .Additional colocation constraint options for multi-state resources [width="95%",cols="1m,1,3<",options="header",align="center"] |========================================================= |Field |Default |Description |rsc-role |Started |An additional attribute of colocation constraints that specifies the role that +rsc+ must be in. Allowed values: +Started+, +Master+, +Slave+. indexterm:[rsc-role,Ordering Constraints] indexterm:[Constraints,Ordering,rsc-role] |with-rsc-role |Started |An additional attribute of colocation constraints that specifies the role that +with-rsc+ must be in. Allowed values: +Started+, +Master+, +Slave+. indexterm:[with-rsc-role,Ordering Constraints] indexterm:[Constraints,Ordering,with-rsc-role] |========================================================= .Constraints involving multi-state resources ====== [source,XML] ------- ------- ====== In the example above, +myApp+ will wait until one of the database copies has been started and promoted to master before being started itself on the same node. Only if no copies can be promoted will +myApp+ be prevented from being active. Additionally, the cluster will wait for +myApp+ to be stopped before demoting the database. Colocation of a primitive or group resource with a multi-state resource means that it can run on any machine with an active copy of the multi-state resource that has the specified role (+master+ or +slave+). In the example above, the cluster will choose a location based on where database is running as a +master+, and if there are multiple +master+ instances it will also factor in +myApp+'s own location preferences when deciding which location to choose. Colocation with regular clones and other multi-state resources is also possible. In such cases, the set of allowed locations for the +rsc+ clone is (after role filtering) limited to nodes on which the +with-rsc+ multi-state resource is (or will be) in the specified role. Placement is then performed as normal. ==== Using Multi-state Resources in Colocation Sets ==== .Additional colocation set options relevant to multi-state resources [width="95%",cols="1m,1,6<",options="header",align="center"] |========================================================= |Field |Default |Description |role |Started |The role that 'all members' of the set must be in. Allowed values: +Started+, +Master+, +Slave+. indexterm:[role,Ordering Constraints] indexterm:[Constraints,Ordering,role] |========================================================= In the following example +B+'s master must be located on the same node as +A+'s master. Additionally resources +C+ and +D+ must be located on the same node as +A+'s and +B+'s masters. .Colocate C and D with A's and B's master instances ====== [source,XML] ------- ------- ====== ==== Using Multi-state Resources in Ordering Sets ==== .Additional ordered set options relevant to multi-state resources [width="95%",cols="1m,1,3<",options="header",align="center"] |========================================================= |Field |Default |Description |action |value of +first-action+ |An additional attribute of ordering constraint sets that specifies the action that applies to 'all members' of the set. Allowed values: +start+, +stop+, +promote+, +demote+. indexterm:[action,Ordering Constraints] indexterm:[Constraints,Ordering,action] |========================================================= .Start C and D after first promoting A and B ====== [source,XML] ------- ------- ====== In the above example, +B+ cannot be promoted to a master role until +A+ has been promoted. Additionally, resources +C+ and +D+ must wait until +A+ and +B+ have been promoted before they can start. === Multi-state Stickiness === indexterm:[resource-stickiness,Multi-State] As with regular clones, multi-state resources are slightly sticky by default. See <> for details. [[s-master-scores]] === Which Resource Instance is Promoted === During the start operation, most resource agents should call the `crm_master` utility. This tool automatically detects both the resource and host and should be used to set a preference for being promoted. Based on this, +master-max+, and +master-node-max+, the instance(s) with the highest preference will be promoted. An alternative is to create a location constraint that indicates which nodes are most preferred as masters. .Explicitly preferring node1 to be promoted to master ====== [source,XML] ------- ------- ====== === Requirements for Multi-state Resource Agents === Since multi-state resources are an extension of cloned resources, all the requirements for resource agents that support clones are also requirements for resource agents that support multi-state resources. Additionally, multi-state resources require two extra actions, +demote+ and +promote+, which are responsible for changing the state of the resource. Like +start+ and +stop+, they should return +$\{OCF_SUCCESS}+ if they completed successfully or a relevant error code if they did not. The states can mean whatever you wish, but when the resource is started, it must come up in the mode called +slave+. From there the cluster will decide which instances to promote to +master+. In addition to the clone requirements for monitor actions, agents must also _accurately_ report which state they are in. The cluster relies on the agent to report its status (including role) accurately and does not indicate to the agent what role it currently believes it to be in. .Role implications of OCF return codes [width="95%",cols="1,1<",options="header",align="center"] |========================================================= |Monitor Return Code |Description |OCF_NOT_RUNNING |Stopped indexterm:[Return Code,OCF_NOT_RUNNING] |OCF_SUCCESS |Running (Slave) indexterm:[Return Code,OCF_SUCCESS] |OCF_RUNNING_MASTER |Running (Master) indexterm:[Return Code,OCF_RUNNING_MASTER] |OCF_FAILED_MASTER |Failed (Master) indexterm:[Return Code,OCF_FAILED_MASTER] |Other |Failed (Slave) |========================================================= ==== Multi-state Notifications ==== Like clones, supporting notifications requires the +notify+ action to be implemented. If supported, the notify action will be passed a number of extra variables which, when combined with additional context, can be used to calculate the current state of the cluster and what is about to happen to it. .Environment variables supplied with multi-state notify actions footnote:[Emphasized variables are specific to +Master+ resources, and all behave in the same manner as described for Clone resources.] [width="95%",cols="5,3<",options="header",align="center"] |========================================================= |Variable |Description |OCF_RESKEY_CRM_meta_notify_type |Allowed values: +pre+, +post+ indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,type] indexterm:[type,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_operation |Allowed values: +start+, +stop+ indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,operation] indexterm:[operation,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_active_resource |Resources that are running indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,active_resource] indexterm:[active_resource,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_inactive_resource |Resources that are not running indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,inactive_resource] indexterm:[inactive_resource,Notification Environment Variable] |_OCF_RESKEY_CRM_meta_notify_master_resource_ |Resources that are running in +Master+ mode indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,master_resource] indexterm:[master_resource,Notification Environment Variable] |_OCF_RESKEY_CRM_meta_notify_slave_resource_ |Resources that are running in +Slave+ mode indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,slave_resource] indexterm:[slave_resource,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_start_resource |Resources to be started indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,start_resource] indexterm:[start_resource,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_stop_resource |Resources to be stopped indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,stop_resource] indexterm:[stop_resource,Notification Environment Variable] |_OCF_RESKEY_CRM_meta_notify_promote_resource_ |Resources to be promoted indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,promote_resource] indexterm:[promote_resource,Notification Environment Variable] |_OCF_RESKEY_CRM_meta_notify_demote_resource_ |Resources to be demoted indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,demote_resource] indexterm:[demote_resource,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_start_uname |Nodes on which resources will be started indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,start_uname] indexterm:[start_uname,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_stop_uname |Nodes on which resources will be stopped indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,stop_uname] indexterm:[stop_uname,Notification Environment Variable] |_OCF_RESKEY_CRM_meta_notify_promote_uname_ |Nodes on which resources will be promoted indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,promote_uname] indexterm:[promote_uname,Notification Environment Variable] |_OCF_RESKEY_CRM_meta_notify_demote_uname_ |Nodes on which resources will be demoted indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,demote_uname] indexterm:[demote_uname,Notification Environment Variable] |OCF_RESKEY_CRM_meta_notify_active_uname |Nodes on which resources are running indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,active_uname] indexterm:[active_uname,Notification Environment Variable] |_OCF_RESKEY_CRM_meta_notify_master_uname_ |Nodes on which resources are running in +Master+ mode indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,master_uname] indexterm:[master_uname,Notification Environment Variable] |_OCF_RESKEY_CRM_meta_notify_slave_uname_ |Nodes on which resources are running in +Slave+ mode indexterm:[Environment Variable,OCF_RESKEY_CRM_meta_notify_,slave_uname] indexterm:[slave_uname,Notification Environment Variable] |========================================================= ==== Proper Interpretation of Multi-state Notification Environment Variables ==== .Pre-notification (demote): * +Active+ resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+ * +Master+ resources: +$OCF_RESKEY_CRM_meta_notify_master_resource+ * +Slave+ resources: +$OCF_RESKEY_CRM_meta_notify_slave_resource+ * Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+ * Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+ * Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ .Post-notification (demote) / Pre-notification (stop): * +Active+ resources: +$OCF_RESKEY_CRM_meta_notify_active_resource+ * +Master+ resources: ** +$OCF_RESKEY_CRM_meta_notify_master_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * +Slave+ resources: +$OCF_RESKEY_CRM_meta_notify_slave_resource+ * Inactive resources: +$OCF_RESKEY_CRM_meta_notify_inactive_resource+ * Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+ * Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ .Post-notification (stop) / Pre-notification (start) * +Active+ resources: ** +$OCF_RESKEY_CRM_meta_notify_active_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * +Master+ resources: ** +$OCF_RESKEY_CRM_meta_notify_master_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * +Slave+ resources: ** +$OCF_RESKEY_CRM_meta_notify_slave_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * Inactive resources: ** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+ * Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ .Post-notification (start) / Pre-notification (promote) * +Active+ resources: ** +$OCF_RESKEY_CRM_meta_notify_active_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+ * +Master+ resources: ** +$OCF_RESKEY_CRM_meta_notify_master_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * +Slave+ resources: ** +$OCF_RESKEY_CRM_meta_notify_slave_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Inactive resources: ** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+ * Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ .Post-notification (promote) * +Active+ resources: ** +$OCF_RESKEY_CRM_meta_notify_active_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+ * +Master+ resources: ** +$OCF_RESKEY_CRM_meta_notify_master_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_demote_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_promote_resource+ * +Slave+ resources: ** +$OCF_RESKEY_CRM_meta_notify_slave_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_start_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_promote_resource+ * Inactive resources: ** +$OCF_RESKEY_CRM_meta_notify_inactive_resource+ ** plus +$OCF_RESKEY_CRM_meta_notify_stop_resource+ ** minus +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources to be started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources to be promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+ * Resources to be demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * Resources to be stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ * Resources that were started: +$OCF_RESKEY_CRM_meta_notify_start_resource+ * Resources that were promoted: +$OCF_RESKEY_CRM_meta_notify_promote_resource+ * Resources that were demoted: +$OCF_RESKEY_CRM_meta_notify_demote_resource+ * Resources that were stopped: +$OCF_RESKEY_CRM_meta_notify_stop_resource+ [[s-resource-bundle]] == Bundles - Isolated Environments == indexterm:[bundle] indexterm:[Resource,bundle] indexterm:[Docker,bundle] indexterm:[rkt,bundle] Pacemaker supports a special syntax for launching a https://en.wikipedia.org/wiki/Operating-system-level_virtualization[container] with any infrastructure it requires: the 'bundle'. Pacemaker bundles support https://www.docker.com/[Docker] (since version 1.1.17) and https://coreos.com/rkt/[rkt] (since version 1.1.18) container technologies. footnote:[Docker is a trademark of Docker, Inc. No endorsement by or association with Docker, Inc. is implied.] .A bundle for a containerized web server ==== [source,XML] ---- ---- ==== === Bundle Properties === .Properties of a Bundle [width="95%",cols="3m,5<",options="header",align="center"] |========================================================= |Field |Description |id |A unique name for the bundle (required) indexterm:[id,bundle] indexterm:[bundle,Property,id] |description |Arbitrary text (not used by Pacemaker) indexterm:[description,bundle] indexterm:[bundle,Property,description] |========================================================= A bundle must contain exactly one ++ or ++ element. === Docker Properties === Before configuring a Docker bundle in Pacemaker, the user must install Docker and supply a fully configured Docker image on every node allowed to run the bundle. Pacemaker will create an implicit +ocf:heartbeat:docker+ resource to manage a bundle's Docker container. The user must ensure that resource agent is installed on every node allowed to run the bundle. .Properties of a Bundle's Docker Element [width="95%",cols="3m,4,5<",options="header",align="center"] |========================================================= |Field |Default |Description |image | |Docker image tag (required) indexterm:[image,Docker] indexterm:[Docker,Property,image] |replicas |Value of +masters+ if that is positive, else 1 |A positive integer specifying the number of container instances to launch indexterm:[replicas,Docker] indexterm:[Docker,Property,replicas] |replicas-per-host |1 |A positive integer specifying the number of container instances allowed to run on a single node indexterm:[replicas-per-host,Docker] indexterm:[Docker,Property,replicas-per-host] |masters |0 |A non-negative integer that, if positive, indicates that the containerized service should be treated as a multistate service, with this many replicas allowed to run the service in the master role indexterm:[masters,Docker] indexterm:[Docker,Property,masters] |network | |If specified, this will be passed to +docker run+ as the https://docs.docker.com/engine/reference/run/#network-settings[network setting] for the Docker container. indexterm:[network,Docker] indexterm:[Docker,Property,network] |run-command |`/usr/sbin/pacemaker_remoted` if bundle contains a +primitive+, otherwise none |This command will be run inside the container when launching it ("PID 1"). If the bundle contains a +primitive+, this command 'must' start pacemaker_remoted (but could, for example, be a script that does other stuff, too). indexterm:[run-command,Docker] indexterm:[Docker,Property,run-command] |options | |Extra command-line options to pass to `docker run` indexterm:[options,Docker] indexterm:[Docker,Property,options] |========================================================= === rkt Properties === Before configuring a rkt bundle in Pacemaker, the user must install rkt and supply a fully configured container image on every node allowed to run the bundle. Pacemaker will create an implicit +ocf:heartbeat:rkt+ resource to manage a bundle's rkt container. The user must ensure that resource agent is installed on every node allowed to run the bundle. .Properties of a Bundle's rkt Element [width="95%",cols="3m,4,5<",options="header",align="center"] |========================================================= |Field |Default |Description |image | |Container image tag (required) indexterm:[image,rkt] indexterm:[rkt,Property,image] |replicas |Value of +masters+ if that is positive, else 1 |A positive integer specifying the number of container instances to launch indexterm:[replicas,rkt] indexterm:[rkt,Property,replicas] |replicas-per-host |1 |A positive integer specifying the number of container instances allowed to run on a single node indexterm:[replicas-per-host,rkt] indexterm:[rkt,Property,replicas-per-host] |masters |0 |A non-negative integer that, if positive, indicates that the containerized service should be treated as a multistate service, with this many replicas allowed to run the service in the master role indexterm:[masters,rkt] indexterm:[rkt,Property,masters] |network | |If specified, this will be passed to +rkt run+ as the network setting for the rkt container. indexterm:[network,rkt] indexterm:[rkt,Property,network] |run-command |`/usr/sbin/pacemaker_remoted` if bundle contains a +primitive+, otherwise none |This command will be run inside the container when launching it ("PID 1"). If the bundle contains a +primitive+, this command 'must' start pacemaker_remoted (but could, for example, be a script that does other stuff, too). indexterm:[run-command,rkt] indexterm:[rkt,Property,run-command] |options | |Extra command-line options to pass to `rkt run` indexterm:[options,rkt] indexterm:[rkt,Property,options] |========================================================= === Bundle Network Properties === A bundle may optionally contain one ++ element. indexterm:[bundle,network] .Properties of a Bundle's Network Element [width="95%",cols="2m,1,4<",options="header",align="center"] |========================================================= |Field |Default |Description |ip-range-start | |If specified, Pacemaker will create an implicit +ocf:heartbeat:IPaddr2+ resource for each container instance, starting with this IP address, using up to +replicas+ sequential addresses. These addresses can be used from the host's network to reach the service inside the container, though it is not visible within the container itself. Only IPv4 addresses are currently supported. indexterm:[ip-range-start,network] indexterm:[network,Property,ip-range-start] |host-netmask |32 |If +ip-range-start+ is specified, the IP addresses are created with this CIDR netmask (as a number of bits). indexterm:[host-netmask,network] indexterm:[network,Property,host-netmask] |host-interface | |If +ip-range-start+ is specified, the IP addresses are created on this host interface (by default, it will be determined from the IP address). indexterm:[host-interface,network] indexterm:[network,Property,host-interface] |control-port |3121 |If the bundle contains a +primitive+, the cluster will use this integer TCP port for communication with Pacemaker Remote inside the container. Changing this is useful when the container is unable to listen on the default port, for example, when the container uses the host's network rather than +ip-range-start+ (in which case +replicas-per-host+ must be 1), or when the bundle may run on a Pacemaker Remote node that is already listening on the default port. Any PCMK_remote_port environment variable set on the host or in the container is ignored for bundle connections. indexterm:[control-port,network] indexterm:[network,Property,control-port] |========================================================= [[s-resource-bundle-note-replica-names]] [NOTE] ==== If +ip-range-start+ is used, Pacemaker will automatically ensure that +/etc/hosts+ inside the containers has entries for each replica and its assigned IP. Replicas are named by the bundle id plus a dash and an integer counter starting with zero. For example, if a bundle named +httpd-bundle+ has +replicas=2+, its containers will be named +httpd-bundle-0+ and +httpd-bundle-1+. ==== Additionally, a ++ element may optionally contain one or more ++ elements. indexterm:[bundle,network,port-mapping] .Properties of a Bundle's Port-Mapping Element [width="95%",cols="2m,1,4<",options="header",align="center"] |========================================================= |Field |Default |Description |id | |A unique name for the port mapping (required) indexterm:[id,port-mapping] indexterm:[port-mapping,Property,id] |port | |If this is specified, connections to this TCP port number on the host network (on the container's assigned IP address, if +ip-range-start+ is specified) will be forwarded to the container network. Exactly one of +port+ or +range+ must be specified in a +port-mapping+. indexterm:[port,port-mapping] indexterm:[port-mapping,Property,port] |internal-port |value of +port+ |If +port+ and this are specified, connections to +port+ on the host's network will be forwarded to this port on the container network. indexterm:[internal-port,port-mapping] indexterm:[port-mapping,Property,internal-port] |range | |If this is specified, connections to these TCP port numbers (expressed as 'first_port'-'last_port') on the host network (on the container's assigned IP address, if +ip-range-start+ is specified) will be forwarded to the same ports in the container network. Exactly one of +port+ or +range+ must be specified in a +port-mapping+. indexterm:[range,port-mapping] indexterm:[port-mapping,Property,range] |========================================================= [NOTE] ==== If the bundle contains a +primitive+, Pacemaker will automatically map the +control-port+, so it is not necessary to specify that port in a +port-mapping+. ==== === Bundle Storage Properties === A bundle may optionally contain one ++ element. A ++ element has no properties of its own, but may contain one or more ++ elements. indexterm:[bundle,storage,storage-mapping] .Properties of a Bundle's Storage-Mapping Element [width="95%",cols="2m,1,4<",options="header",align="center"] |========================================================= |Field |Default |Description |id | |A unique name for the storage mapping (required) indexterm:[id,storage-mapping] indexterm:[storage-mapping,Property,id] |source-dir | |The absolute path on the host's filesystem that will be mapped into the container. Exactly one of +source-dir+ and +source-dir-root+ must be specified in a +storage-mapping+. indexterm:[source-dir,storage-mapping] indexterm:[storage-mapping,Property,source-dir] |source-dir-root | |The start of a path on the host's filesystem that will be mapped into the container, using a different subdirectory on the host for each container instance. The subdirectory will be named the same as the bundle host name, as described in <>. Exactly one of +source-dir+ and +source-dir-root+ must be specified in a +storage-mapping+. indexterm:[source-dir-root,storage-mapping] indexterm:[storage-mapping,Property,source-dir-root] |target-dir | |The path name within the container where the host storage will be mapped (required) indexterm:[target-dir,storage-mapping] indexterm:[storage-mapping,Property,target-dir] |options | |File system mount options to use when mapping the storage indexterm:[options,storage-mapping] indexterm:[storage-mapping,Property,options] |========================================================= [NOTE] ==== Pacemaker does not define the behavior if the source directory does not already exist on the host. However, it is expected that the container technology and/or its resource agent will create the source directory in that case. ==== [NOTE] ==== If the bundle contains a +primitive+, Pacemaker will automatically map the equivalent of +source-dir=/etc/pacemaker/authkey target-dir=/etc/pacemaker/authkey+ and +source-dir-root=/var/log/pacemaker/bundles target-dir=/var/log+ into the container, so it is not necessary to specify those paths in a +storage-mapping+. (If the DC node has the PCMK_authkey_location variable set, that will be used as the source instead of `/etc/pacemaker/authkey`; the value should be identical on all nodes, if used. The user should not set the PCMK_authkey_location environment variable inside the container.) ==== === Bundle Primitive === A bundle may optionally contain one ++ resource (see <>). The primitive may have operations, instance attributes and meta-attributes defined, as usual. If a bundle contains a primitive resource, the container image must include the Pacemaker Remote daemon, and at least one of +ip-range-start+ or +control-port+ must be configured in the bundle. Pacemaker will create an implicit +ocf:pacemaker:remote+ resource for the connection, launch Pacemaker Remote within the container, and monitor and manage the primitive resource via Pacemaker Remote. If the bundle has more than one container instance (replica), the primitive resource will function as an implicit clone (see <>) -- a multistate clone if the bundle has +masters+ greater than zero (see <>). [IMPORTANT] ==== Containers in bundles with a +primitive+ must have an accessible networking environment, so that Pacemaker on the cluster nodes can contact Pacemaker Remote inside the container. For example, the Docker option `--net=none` should not be used with a +primitive+. The default (using a distinct network space inside the container) works in combination with +ip-range-start+. If the Docker option `--net=host` is used (making the container share the host's network space), a unique +control-port+ should be specified for each bundle. Any firewall must allow access to the +control-port+. ==== [[s-bundle-attributes]] === Bundle Node Attributes === If the bundle has a +primitive+, the primitive's resource agent may want to set node attributes such as <>. However, with containers, it is not apparent which node should get the attribute. If the container uses shared storage that is the same no matter which node the container is hosted on, then it is appropriate to use the master score on the bundle node itself. On the other hand, if the container uses storage exported from the underlying host, then it may be more appropriate to use the master score on the underlying host. Since this depends on the particular situation, the +container-attribute-target+ resource meta-attribute allows the user to specify which approach to use. If it is set to +host+, then user-defined node attributes will be checked on the underlying host. If it is anything else, the local node (in this case the bundle node) is used as usual. This only applies to user-defined attributes; the cluster will always check the local node for cluster-defined attributes such as +#uname+. If +container-attribute-target+ is +host+, the cluster will pass additional environment variables to the primitive's resource agent that allow it to set node attributes appropriately: +container_attribute_target+ (identical to the meta-attribute value) and +physical_host+ (the name of the underlying host). [NOTE] ==== It is up to the resource agent to check for the additional variables and use them when setting node attributes. ==== === Bundle Meta-Attributes === Any meta-attribute set on a bundle will be inherited by the bundle's primitive and any resources implicitly created by Pacemaker for the bundle. This includes options such as +priority+, +target-role+, and +is-managed+. See <> for more information. === Limitations of Bundles === -Bundle support is considered experimental. Cleaning up a running bundle, or -restarting pacemaker while a bundle is unmanaged or the cluster is in -maintenance mode, may cause the bundle to fail. The feature is believed to -be otherwise production-ready as of version 1.1.18. +Restarting pacemaker while a bundle is unmanaged or the cluster is in +maintenance mode may cause the bundle to fail. Bundles may not be cloned or included in groups. This includes the bundle's primitive and any resources implicitly created by Pacemaker for the bundle. Bundles do not have instance attributes, utilization attributes, or operations, though a bundle's primitive may have them. A bundle with a primitive can run on a Pacemaker Remote node only if the bundle uses a distinct +control-port+. - -Interacting directly with any resource or guest node implicitly created by -Pacemaker for the bundle is strongly discouraged and likely to cause problems.