diff --git a/doc/Clusters_from_Scratch/en-US/Ap-Configuration.txt b/doc/Clusters_from_Scratch/en-US/Ap-Configuration.txt index 5852e7eb04..ef11ded1a0 100644 --- a/doc/Clusters_from_Scratch/en-US/Ap-Configuration.txt +++ b/doc/Clusters_from_Scratch/en-US/Ap-Configuration.txt @@ -1,498 +1,468 @@ [appendix] == Configuration Recap == === Final Cluster Configuration === -ifdef::pcs[] - -[source,C] ---- -# pcs resource +[root@pcmk-1 ~]# pcs resource Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-2 pcmk-1 ] + Masters: [ pcmk-1 pcmk-2 ] Clone Set: dlm-clone [dlm] - Started: [ pcmk-2 pcmk-1 ] + Started: [ pcmk-1 pcmk-2 ] Clone Set: ClusterIP-clone [ClusterIP] (unique) - ClusterIP:0 (ocf::heartbeat:IPaddr2) Started - ClusterIP:1 (ocf::heartbeat:IPaddr2) Started + ClusterIP:0 (ocf::heartbeat:IPaddr2): Started + ClusterIP:1 (ocf::heartbeat:IPaddr2): Started Clone Set: WebFS-clone [WebFS] Started: [ pcmk-1 pcmk-2 ] Clone Set: WebSite-clone [WebSite] Started: [ pcmk-1 pcmk-2 ] -# pcs resource rsc defaults +---- + +---- +[root@pcmk-1 ~]# pcs resource defaults resource-stickiness: 100 -# pcs resource op defaults +---- + +---- +[root@pcmk-1 ~]# pcs resource op defaults timeout: 240s -# pcs stonith +---- + +---- +[root@pcmk-1 ~]# pcs stonith impi-fencing (stonith:fence_ipmilan) Started -# pcs property -dc-version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -cluster-infrastructure: corosync -no-quorum-policy: ignore -stonith-enabled: true -# pcs constraint +---- + +---- +[root@pcmk-1 ~]# pcs property +Cluster Properties: + cluster-infrastructure: corosync + cluster-name: mycluster + dc-version: 1.1.12-a9c8177 + have-watchdog: false + last-lrm-refresh: 1419129162 + stonith-enabled: true +---- + +---- +[root@pcmk-1 ~]# pcs constraint Location Constraints: Ordering Constraints: - ClusterIP-clone then WebSite-clone - WebDataClone then WebSite-clone - WebFS-clone then WebSite-clone + start ClusterIP-clone then start WebSite-clone (kind:Mandatory) + promote WebDataClone then start WebFS-clone (kind:Mandatory) + start WebFS-clone then start WebSite-clone (kind:Mandatory) + start dlm-clone then start WebFS-clone (kind:Mandatory) Colocation Constraints: - WebSite-clone with ClusterIP-clone - WebFS-clone with WebDataClone (with-rsc-role:Master) - WebSite-clone with WebFS-clone -# -# pcs status - -Last updated: Fri Sep 14 13:45:34 2012 -Last change: Fri Sep 14 13:43:13 2012 via cibadmin on pcmk-1 + WebSite-clone with ClusterIP-clone (score:INFINITY) + WebFS-clone with WebDataClone (score:INFINITY) (with-rsc-role:Master) + WebSite-clone with WebFS-clone (score:INFINITY) + WebFS-clone with dlm-clone (score:INFINITY) +---- + +---- +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Mon Dec 22 11:19:17 2014 +Last change: Mon Dec 22 11:03:52 2014 Stack: corosync -Current DC: pcmk-1 (1) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -11 Resources configured. +Current DC: pcmk-2 (2) - partition with quorum +Version: 1.1.12-a9c8177 +2 Nodes configured +11 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: + impi-fencing (stonith:fence_ipmilan): Started pcmk-1 Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-2 pcmk-1 ] + Masters: [ pcmk-1 pcmk-2 ] Clone Set: dlm-clone [dlm] Started: [ pcmk-1 pcmk-2 ] Clone Set: ClusterIP-clone [ClusterIP] (unique) - ClusterIP:0 (ocf::heartbeat:IPaddr2): Started pcmk-1 - ClusterIP:1 (ocf::heartbeat:IPaddr2): Started pcmk-2 + ClusterIP:0 (ocf::heartbeat:IPaddr2): Started pcmk-2 + ClusterIP:1 (ocf::heartbeat:IPaddr2): Started pcmk-1 Clone Set: WebFS-clone [WebFS] Started: [ pcmk-1 pcmk-2 ] Clone Set: WebSite-clone [WebSite] Started: [ pcmk-1 pcmk-2 ] - impi-fencing (stonith:fence_ipmilan): Started + +PCSD Status: + pcmk-1: Online + pcmk-2: Online + +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -In xml it should look similar to this. +---- +[root@pcmk-1 ~]# pcs cluster cib +---- [source,XML] ---- - + - + + - + + - - + + + + + + + + + + + + + + + + + - + + + + + + - - + + + - + - + + + + - + - + + + + + + - + + + - - - - - - - - - - - - - + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + ---- -endif::[] - -ifdef::crmsh[] -..... -# crm configure show -node 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" -..... -endif::[] - === Node List === -The list of cluster nodes is automatically populated by the cluster. - -ifdef::pcs[] -..... +---- +[root@pcmk-1 ~]# pcs status nodes Pacemaker Nodes: - Online: [ pcmk-1 pcmk-2 ] -..... -endif::[] - -ifdef::crmsh[] -..... -node pcmk-1 -node pcmk-2 -..... -endif::[] + Online: pcmk-1 pcmk-2 + Standby: + Offline: +---- === Cluster Options === -This is where the cluster automatically stores some information about -the cluster - -* dc-version - the version (including upstream source-code hash) of Pacemaker used on the DC - -* cluster-infrastructure - the cluster infrastructure being used (heartbeat or openais) - -* expected-quorum-votes - the maximum number of nodes expected to be part of the cluster - -and where the admin can set options that control the way the cluster -operates - -* stonith-enabled=true - Make use of STONITH - -* no-quorum-policy=ignore - Ignore loss of quorum and continue to host resources. - -ifdef::pcs[] -[source,C] ---- -# pcs property -dc-version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -cluster-infrastructure: corosync -no-quorum-policy: ignore -stonith-enabled: true +[root@pcmk-1 ~]# pcs property +Cluster Properties: + cluster-infrastructure: corosync + cluster-name: mycluster + dc-version: 1.1.12-a9c8177 + have-watchdog: false + last-lrm-refresh: 1419129162 + stonith-enabled: true ---- -endif::[] -ifdef::crmsh[] -..... -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" -..... -endif::[] +The output shows state information automatically obtained about the cluster, including: +* *cluster-infrastructure* - the cluster communications layer in use (heartbeat or corosync) +* *cluster-name* - the cluster name chosen by the administrator when the cluster was created +* *dc-version* - the version (including upstream source-code hash) of Pacemaker used on the Designated Controller -=== Resources === +The output also shows options set by the administrator that control the way the cluster operates, including: +* *stonith-enabled=true* - whether the cluster is allowed to use STONITH resources +=== Resources === ==== Default Options ==== -Here we configure cluster options that apply to every resource. - -ifdef::pcs[] -* resource-stickiness - Specify the aversion to moving resources to other machines -[source,C] ---- -# pcs resource rsc defaults +[root@pcmk-1 ~]# pcs resource defaults resource-stickiness: 100 ---- -endif::[] -ifdef::crmsh[] -* resource-stickiness - Specify the aversion to moving resources to other machines -..... -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -..... -endif::[] +This shows cluster option defaults that apply to every resource that does not +explicitly set the option itself. Above: +* *resource-stickiness* - Specify the aversion to moving healthy resources to other machines ==== Fencing ==== -ifdef::pcs[] -[source,C] ---- -# pcs stonith show - impi-fencing (stonith:fence_ipmilan) Started -# pcs stonith show impi-fencing -Resource: impi-fencing - pcmk_host_list: pcmk-1 pcmk-2 - ipaddr: 10.0.0.1 - login: testuser - passwd: acd123 ----- -endif::[] - -ifdef::crmsh[] -..... -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" -clone Fencing rsa-fencing -..... -endif::[] +[root@pcmk-1 ~]# pcs stonith show + ipmi-fencing (stonith:fence_ipmilan) Started +[root@pcmk-1 ~]# pcs stonith show ipmi-fencing + Resource: ipmi-fencing (class=stonith type=fence_ipmilan) + Attributes: ipaddr="10.0.0.1" login="testuser" passwd="acd123" pcmk_host_list="pcmk-1 pcmk-2" + Operations: monitor interval=60s (fence-monitor-interval-60s) +---- ==== Service Address ==== Users of the services provided by the cluster require an unchanging address with which to access it. Additionally, we cloned the address so it will be active on both nodes. An iptables rule (created as part of the resource agent) is used to ensure that each request only gets processed by one of the two clone instances. The additional meta options tell the cluster that we want two instances of the clone (one "request bucket" for each node) and that if one node fails, then the remaining node should hold both. -ifdef::pcs[] -[source,C] ----- -# pcs resource show ClusterIP-clone -Resource: ClusterIP-clone - ip: 192.168.0.120 - cidr_netmask: 32 - clusterip_hash: sourceip - globally-unique: true - clone-max: 2 - clone-node-max: 2 - op monitor interval=30s ----- -endif::[] - -ifdef::crmsh[] -..... -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.101" cidr_netmask="32" clusterip_hash="sourceip" \ - op monitor interval="30s" -clone WebIP ClusterIP - meta globally-unique="true" clone-max="2" clone-node-max="2" -..... -endif::[] - -[NOTE] -======= -TODO: The RA should check for globally-unique=true when cloned -======= +---- +[root@pcmk-1 ~]# pcs resource show ClusterIP-clone + Clone: ClusterIP-clone + Meta Attrs: clone-max=2 clone-node-max=2 globally-unique=true + Resource: ClusterIP (class=ocf provider=heartbeat type=IPaddr2) + Attributes: ip=192.168.122.120 cidr_netmask=32 clusterip_hash=sourceip + Operations: start interval=0s timeout=20s (ClusterIP-start-timeout-20s) + stop interval=0s timeout=20s (ClusterIP-stop-timeout-20s) + monitor interval=30s (ClusterIP-monitor-interval-30s) +---- ==== DRBD - Shared Storage ==== -Here we define the DRBD service and specify which DRBD resource (from -drbd.conf) it should manage. We make it a master/slave resource and, in -order to have an active/active setup, allow both instances to be promoted -by specifying master-max=2. We also set the notify option so that the -cluster will tell DRBD agent when it's peer changes state. +Here, we define the DRBD service and specify which DRBD resource (from +/etc/drbd.d/*.res) it should manage. We make it a master/slave resource and, in +order to have an active/active setup, allow both instances to be promoted to master +at the same time. We also set the notify option so that the +cluster will tell DRBD agent when its peer changes state. -ifdef::pcs[] -[source,C] ---- -# pcs resource show WebDataClone -Resource: WebDataClone - drbd_resource: wwwdata - master-node-max: 1 - clone-max: 2 - clone-node-max: 1 - notify: true - master-max: 2 - op monitor interval=60s -# pcs constraint ref WebDataClone +[root@pcmk-1 ~]# pcs resource show WebDataClone + Master: WebDataClone + Meta Attrs: master-max=2 master-node-max=1 clone-max=2 clone-node-max=1 notify=true + Resource: WebData (class=ocf provider=linbit type=drbd) + Attributes: drbd_resource=wwwdata + Operations: start interval=0s timeout=240 (WebData-start-timeout-240) + promote interval=0s timeout=90 (WebData-promote-timeout-90) + demote interval=0s timeout=90 (WebData-demote-timeout-90) + stop interval=0s timeout=100 (WebData-stop-timeout-100) + monitor interval=60s (WebData-monitor-interval-60s) +[root@pcmk-1 ~]# pcs constraint ref WebDataClone Resource: WebDataClone colocation-WebFS-WebDataClone-INFINITY order-WebDataClone-WebFS-mandatory ---- -endif::[] - -ifdef::crmsh[] -..... -primitive WebData ocf:linbit:drbd \ - params drbd_resource="wwwdata" \ - op monitor interval="60s" -ms WebDataClone WebData \ - meta master-max="2" master-node-max="1" clone-max="2" clone-node-max="1" notify="true" -..... -endif::[] - ==== Cluster Filesystem ==== The cluster filesystem ensures that files are read and written correctly. We need to specify the block device (provided by DRBD), where we want it -mounted and that we are using GFS2. Again it is a clone because it is +mounted and that we are using GFS2. Again, it is a clone because it is intended to be active on both nodes. The additional constraints ensure -that it can only be started on nodes with active gfs-control and drbd -instances. +that it can only be started on nodes with active DLM and DRBD instances. -ifdef::pcs[] -[source,C] ---- -# pcs resource show WebFS-clone -Resource: WebFS-clone - device: /dev/drbd/by-res/wwwdata - directory: /var/www/html - fstype: gfs2 -# pcs constraint ref WebFS-clone +[root@pcmk-1 ~]# pcs resource show WebFS-clone + Clone: WebFS-clone + Resource: WebFS (class=ocf provider=heartbeat type=Filesystem) + Attributes: device=/dev/drbd1 directory=/var/www/html fstype=gfs2 + Operations: start interval=0s timeout=60 (WebFS-start-timeout-60) + stop interval=0s timeout=60 (WebFS-stop-timeout-60) + monitor interval=20 timeout=40 (WebFS-monitor-interval-20) +[root@pcmk-1 ~]# pcs constraint ref WebFS-clone Resource: WebFS-clone colocation-WebFS-WebDataClone-INFINITY colocation-WebSite-WebFS-INFINITY - order-WebFS-WebSite-mandatory + colocation-WebFS-clone-dlm-clone-INFINITY order-WebDataClone-WebFS-mandatory + order-WebFS-WebSite-mandatory + order-dlm-clone-WebFS-clone-mandatory ---- -endif::[] - -ifdef::crmsh[] -..... -primitive WebFS ocf:heartbeat:Filesystem \ - params device="/dev/drbd/by-res/wwwdata" directory="/var/www/html" fstype="gfs2" -clone WebFSClone WebFS -colocation WebFS-with-gfs-control inf: WebFSClone gfs-clone -colocation fs_on_drbd inf: WebFSClone WebDataClone:Master -order WebFS-after-WebData inf: WebDataClone:promote WebFSClone:start -order start-WebFS-after-gfs-control inf: gfs-clone WebFSClone -..... -endif::[] ==== Apache ==== -Lastly we have the actual service, Apache. We need only tell the cluster -where to find it's main configuration file and restrict it to running on -nodes that have the required filesystem mounted and the IP address -active. +Lastly, we have the actual service, Apache. We need only tell the cluster +where to find its main configuration file and restrict it to running on +nodes that have the required filesystem mounted and the IP address active. -ifdef::pcs[] -[source,C] ---- -# pcs resource show WebSite-clone -Resource: WebSite-clone - configfile: /etc/httpd/conf/httpd.conf - statusurl: http://localhost/server-status - master-max: 2 - op monitor interval=1min -# pcs constraint ref WebSite-clone +[root@pcmk-1 ~]# pcs resource show WebSite-clone + Clone: WebSite-clone + Resource: WebSite (class=ocf provider=heartbeat type=apache) + Attributes: configfile=/etc/httpd/conf/httpd.conf statusurl=http://localhost/server-status + Operations: start interval=0s timeout=40s (WebSite-start-timeout-40s) + stop interval=0s timeout=60s (WebSite-stop-timeout-60s) + monitor interval=1min (WebSite-monitor-interval-1min) +[root@pcmk-1 ~]# pcs constraint ref WebSite-clone Resource: WebSite-clone colocation-WebSite-ClusterIP-INFINITY colocation-WebSite-WebFS-INFINITY order-ClusterIP-WebSite-mandatory order-WebFS-WebSite-mandatory ---- -endif::[] - -ifdef::crmsh[] -..... -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -clone WebSiteClone WebSite -colocation WebSite-with-WebFS inf: WebSiteClone WebFSClone -colocation website-with-ip inf: WebSiteClone WebIP -order apache-after-ip inf: WebIP WebSiteClone -order WebSite-after-WebFS inf: WebFSClone WebSiteClone -..... -endif::[] - diff --git a/doc/Clusters_from_Scratch/en-US/Ap-Corosync-Conf.txt b/doc/Clusters_from_Scratch/en-US/Ap-Corosync-Conf.txt index 0ab5d5767f..df14dd1d60 100644 --- a/doc/Clusters_from_Scratch/en-US/Ap-Corosync-Conf.txt +++ b/doc/Clusters_from_Scratch/en-US/Ap-Corosync-Conf.txt @@ -1,121 +1,33 @@ [appendix] - == Sample Corosync Configuration == -ifdef::pcs[] -.Sample corosync.conf for two-node cluster using a node list. +.Sample +corosync.conf+ for two-node cluster created by `pcs`. ..... -# Please read the corosync.conf.5 manual page totem { version: 2 secauth: off cluster_name: mycluster transport: udpu } nodelist { node { ring0_addr: pcmk-1 nodeid: 1 - } + } node { ring0_addr: pcmk-2 nodeid: 2 - } + } } quorum { - provider: corosync_votequorum -} - -logging { - to_syslog: yes -} -..... -endif::[] - -ifdef::crmsh[] -.Sample Corosync.conf for a two-node cluster using multicast. -..... -# Please read the corosync.conf.5 manual page -totem { - version: 2 - - # cypto_cipher and crypto_hash: Used for mutual node authentication. - # If you choose to enable this, then do remember to create a shared - # secret with "corosync-keygen". - crypto_cipher: none - crypto_hash: none - - # interface: define at least one interface to communicate - # over. If you define more than one interface stanza, you must - # also set rrp_mode. - interface { - # Rings must be consecutively numbered, starting at 0. - ringnumber: 0 - # This is normally the *network* address of the - # interface to bind to. This ensures that you can use - # identical instances of this configuration file - # across all your cluster nodes, without having to - # modify this option. -bindnetaddr: 192.168.122.0 - # However, if you have multiple physical network - # interfaces configured for the same subnet, then the - # network address alone is not sufficient to identify - # the interface Corosync should bind to. In that case, - # configure the *host* address of the interface - # instead: - # bindnetaddr: 192.168.1.1 - # When selecting a multicast address, consider RFC - # 2365 (which, among other things, specifies that - # 239.255.x.x addresses are left to the discretion of - # the network administrator). Do not reuse multicast - # addresses across multiple Corosync clusters sharing - # the same network. -mcastaddr: 239.255.1.1 - # Corosync uses the port you specify here for UDP - # messaging, and also the immediately preceding - # port. Thus if you set this to 5405, Corosync sends - # messages over UDP ports 5405 and 5404. -mcastport: 4000 - # Time-to-live for cluster communication packets. The - # number of hops (routers) that this ring will allow - # itself to pass. Note that multicast routing must be - # specifically enabled on most network routers. - ttl: 1 - } +provider: corosync_votequorum +two_node: 1 } logging { - # Log the source file and line where messages are being - # generated. When in doubt, leave off. Potentially useful for - # debugging. - fileline: off - # Log to standard error. When in doubt, set to no. Useful when - # running in the foreground (when invoking "corosync -f") - to_stderr: no - # Log to a log file. When set to "no", the "logfile" option - # must not be set. - to_logfile: yes - logfile: /var/log/cluster/corosync.log - # Log to the system log daemon. When in doubt, set to yes. - to_syslog: yes - # Log debug messages (very verbose). When in doubt, leave off. - debug: off - # Log messages with time stamps. When in doubt, set to on - # (unless you are only logging to syslog, where double - # timestamps can be annoying). - timestamp: on - logger_subsys { - subsys: QUORUM - debug: off - } -} - -quorum { - provider: corosync_votequorum - expected_votes: 2 +to_syslog: yes } ..... -endif::[] diff --git a/doc/Clusters_from_Scratch/en-US/Ap-Reading.txt b/doc/Clusters_from_Scratch/en-US/Ap-Reading.txt index a8ef3e396b..26d5d7e117 100644 --- a/doc/Clusters_from_Scratch/en-US/Ap-Reading.txt +++ b/doc/Clusters_from_Scratch/en-US/Ap-Reading.txt @@ -1,12 +1,12 @@ [appendix] == Further Reading == - Project Website -http://www.clusterlabs.org +http://www.clusterlabs.org/ -- Cluster Commands -A comprehensive guide to cluster commands has been written by SuSE and can be found at: +- SuSE has a comprehensive guide to cluster commands (though using the `crmsh` command-line + shell rather than `pcs`) at: http://www.suse.com/documentation/sle_ha/book_sleha/?page=/documentation/sle_ha/book_sleha/data/book_sleha.html - Corosync - http://www.corosync.org + http://www.corosync.org/ diff --git a/doc/Clusters_from_Scratch/en-US/Book_Info.xml b/doc/Clusters_from_Scratch/en-US/Book_Info.xml index 521394bf8b..e436c02aac 100644 --- a/doc/Clusters_from_Scratch/en-US/Book_Info.xml +++ b/doc/Clusters_from_Scratch/en-US/Book_Info.xml @@ -1,61 +1,67 @@ %BOOK_ENTITIES; ]> Clusters from Scratch Creating Active/Passive and Active/Active Clusters on Fedora Pacemaker 1.1 - 5 + + 8 0 The purpose of this document is to provide a start-to-finish guide to building an example active/passive cluster with Pacemaker and show how it can be converted to an active/active one. The example cluster will use: &DISTRO; &DISTRO_VERSION; as the host operating system Corosync to provide messaging and membership services, Pacemaker to perform resource management, DRBD as a cost-effective alternative to shared storage, GFS2 as the cluster filesystem (in active/active mode) Given the graphical nature of the Fedora install process, a number of screenshots are included. However the guide is primarily composed of commands, the reasons for executing them and their expected outputs. diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Active-Active.txt b/doc/Clusters_from_Scratch/en-US/Ch-Active-Active.txt index 714a0d3158..ca980c42fd 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Active-Active.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Active-Active.txt @@ -1,755 +1,380 @@ -= Conversion to Active/Active = - -== Requirements == += Convert Cluster to Active/Active = The primary requirement for an Active/Active cluster is that the data required for your services is available, simultaneously, on both -machines. Pacemaker makes no requirement on how this is achieved, you -could use a SAN if you had one available, however since DRBD supports -multiple Primaries, we can also use that. +machines. Pacemaker makes no requirement on how this is achieved; you +could use a SAN if you had one available, but since DRBD supports +multiple Primaries, we can continue to use it here. + +== Install Cluster Filesystem Software == The only hitch is that we need to use a cluster-aware filesystem. The one we used earlier with DRBD, ext4, is not one of those. Both OCFS2 -and GFS2 are supported, however here we will use GFS2 which comes with -Fedora 17. - -=== Installing the required Software === - -[source,C] -# yum install -y gfs2-utils dlm kernel-modules-extra -..... -Loaded plugins: langpacks, presto, refresh-packagekit -Resolving Dependencies ---> Running transaction check ----> Package dlm.x86_64 0:3.99.4-1.fc17 will be installed ----> Package gfs2-utils.x86_64 0:3.1.4-3.fc17 will be installed ----> Package kernel-modules-extra.x86_64 0:3.4.4-3.fc17 will be installed ---> Finished Dependency Resolution - -Dependencies Resolved - -================================================================================ - Package Arch Version Repository Size -================================================================================ -Installing: - dlm x86_64 3.99.4-1.fc17 updates 83 k - gfs2-utils x86_64 3.1.4-3.fc17 fedora 214 k - kernel-modules-extra x86_64 3.4.4-3.fc17 updates 1.7 M - -Transaction Summary -================================================================================ -Install 3 Packages - -Total download size: 1.9 M -Installed size: 7.7 M -Downloading Packages: -(1/3): dlm-3.99.4-1.fc17.x86_64.rpm | 83 kB 00:00 -(2/3): gfs2-utils-3.1.4-3.fc17.x86_64.rpm | 214 kB 00:00 -(3/3): kernel-modules-extra-3.4.4-3.fc17.x86_64.rpm | 1.7 MB 00:01 --------------------------------------------------------------------------------- -Total 615 kB/s | 1.9 MB 00:03 -Running Transaction Check -Running Transaction Test -Transaction Test Succeeded -Running Transaction - Installing : kernel-modules-extra-3.4.4-3.fc17.x86_64 1/3 - Installing : gfs2-utils-3.1.4-3.fc17.x86_64 2/3 - Installing : dlm-3.99.4-1.fc17.x86_64 3/3 - Verifying : dlm-3.99.4-1.fc17.x86_64 1/3 - Verifying : gfs2-utils-3.1.4-3.fc17.x86_64 2/3 - Verifying : kernel-modules-extra-3.4.4-3.fc17.x86_64 3/3 - -Installed: - dlm.x86_64 0:3.99.4-1.fc17 - gfs2-utils.x86_64 0:3.1.4-3.fc17 - kernel-modules-extra.x86_64 0:3.4.4-3.fc17 - -Complete! -..... - -== Create a GFS2 Filesystem == +and GFS2 are supported; here, we will use GFS2. -[[GFS2_prep]] -=== Preparation === +On both nodes, install the GFS2 command-line utilities and the +Distributed Lock Manager (DLM) required by cluster filesystems: +---- +# yum install -y gfs2-utils dlm +---- -Before we do anything to the existing partition, we need to make sure it -is unmounted. We do this by telling the cluster to stop the WebFS resource. -This will ensure that other resources (in our case, Apache) using WebFS -are not only stopped, but stopped in the correct order. +== Configure the Cluster for the DLM == -ifdef::pcs[] -[source,C] +The DLM needs to run on both nodes, so we'll start by creating a resource for +it (using the *ocf:pacemaker:controld* resource script), and clone it: ---- -# pcs resource disable WebFS -# pcs resource - ClusterIP (ocf::heartbeat:IPaddr2) Started - WebSite (ocf::heartbeat:apache) Stopped +[root@pcmk-1 ~]# pcs cluster cib dlm_cfg +[root@pcmk-1 ~]# pcs -f dlm_cfg resource create dlm ocf:pacemaker:controld op monitor interval=60s +[root@pcmk-1 ~]# pcs -f dlm_cfg resource clone dlm clone-max=2 clone-node-max=1 +[root@pcmk-1 ~]# pcs -f dlm_cfg resource show + ClusterIP (ocf::heartbeat:IPaddr2): Started + WebSite (ocf::heartbeat:apache): Started Master/Slave Set: WebDataClone [WebData] Masters: [ pcmk-2 ] Slaves: [ pcmk-1 ] - WebFS (ocf::heartbeat:Filesystem) Stopped + WebFS (ocf::heartbeat:Filesystem): Started + Clone Set: dlm-clone [dlm] + Stopped: [ pcmk-1 pcmk-2 ] ---- -endif::[] -ifdef::crmsh[] -[source,C] ------ -# crm resource disable WebFS -# crm_mon -1 -============ -Last updated: Tue Apr 3 14:07:36 2012 -Last change: Tue Apr 3 14:07:15 2012 via cibadmin on pcmk-1 +Activate our new configuration, and see how the cluster responds: +---- +[root@pcmk-1 ~]# pcs cluster cib-push dlm_cfg +CIB updated +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Sat Dec 20 21:53:44 2014 +Last change: Sat Dec 20 21:53:40 2014 Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -5 Resources configured. -============ +Current DC: pcmk-1 (1) - partition with quorum +Version: 1.1.12-a9c8177 +2 Nodes configured +8 Resources configured + Online: [ pcmk-1 pcmk-2 ] - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 +Full list of resources: + + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 + WebSite (ocf::heartbeat:apache): Started pcmk-2 Master/Slave Set: WebDataClone [WebData] Masters: [ pcmk-2 ] Slaves: [ pcmk-1 ] ------ -endif::[] + WebFS (ocf::heartbeat:Filesystem): Started pcmk-2 + ipmi-fencing (stonith:fence_ipmilan): Started pcmk-1 + Clone Set: dlm-clone [dlm] + Started: [ pcmk-1 pcmk-2 ] -[NOTE] -======= +PCSD Status: + pcmk-1: Online + pcmk-2: Online -Note that both Apache and WebFS have been stopped. +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled +---- -======= +[[GFS2_prep]] +== Create and Populate GFS2 Filesystem == -=== Create and Populate an GFS2 Partition === +Before we do anything to the existing partition, we need to make sure it +is unmounted. We do this by telling the cluster to stop the WebFS resource. +This will ensure that other resources (in our case, Apache) using WebFS +are not only stopped, but stopped in the correct order. -Now that the cluster stack and integration pieces are running smoothly, -we can create an GFS2 partition. +---- +[root@pcmk-1 ~]# pcs resource disable WebFS +[root@pcmk-1 ~]# pcs resource + ClusterIP (ocf::heartbeat:IPaddr2): Started + WebSite (ocf::heartbeat:apache): Stopped + Master/Slave Set: WebDataClone [WebData] + Masters: [ pcmk-2 ] + Slaves: [ pcmk-1 ] + WebFS (ocf::heartbeat:Filesystem): Stopped + Clone Set: dlm-clone [dlm] + Started: [ pcmk-1 pcmk-2 ] +---- + +You can see that both Apache and WebFS have been stopped, +and that *pcmk-2* is the current master for the DRBD device. + +Now we can create a new GFS2 filesystem on the DRBD device. [WARNING] ========= - This will erase all previous content stored on the DRBD device. Ensure you have a copy of any important data. - ========= -We need to specify a number of additional parameters when creating a -GFS2 partition. - -First we must use the -p option to specify that we want to use the the -Kernel's DLM. Next we use -j to indicate that it should reserve enough -space for two journals (one per node accessing the filesystem). - -ifdef::pcs[] -Lastly, we use -t to specify the lock table name. The format for this -field is +clustername:fsname+. For the +fsname+, we need to use the same -value as specified in 'corosync.conf' for +cluster_name+. If you setup -corosync with the same cluster name we used in this tutorial, cluster -name will be 'mycluster'. If you are unsure what your cluster name is, -open up /etc/corosync/corosync.conf, or execute the command -'pcs cluster corosync pcmk-1' to view the corosync config. The cluster -name will be in the +totem+ block. -endif::[] - -ifdef::crmsh[] -Lastly, we use -t to specify the lock table name. The format for this -field is +clustername:fsname+. For the +fsname+, we need to use the same -value as specified in 'corosync.conf' for +cluster_name+. Just pick -something unique and descriptive and add somewhere inside the +totem+ -block. For example: - -..... -totem { - version: 2 - - # cypto_cipher and crypto_hash: Used for mutual node authentication. - # If you choose to enable this, then do remember to create a shared - # secret with "corosync-keygen". - crypto_cipher: none - crypto_hash: none - cluster_name: mycluster - ... -..... - -[IMPORTANT] -=========== -Do this on each node in the cluster and be sure to restart them before -continuing. -=========== -endif::[] - [IMPORTANT] =========== -We must run the next command on whichever node last had '/dev/drbd' -mounted. Otherwise you will receive the message: - +Run the next command on whichever node has the DRBD Primary role. +Otherwise, you will receive the message: ----- /dev/drbd1: Read-only file system ----- =========== -[source,C] ----- -# ssh pcmk-2 -- mkfs.gfs2 -p lock_dlm -j 2 -t mycluster:web /dev/drbd1 -This will destroy any data on /dev/drbd1. -It appears to contain: Linux rev 1.0 ext4 filesystem data, UUID=dc45fff3-c47a-4db2-96f7-a8049a323fe4 (extents) (large files) (huge files) +[root@pcmk-2 ~]# mkfs.gfs2 -p lock_dlm -j 2 -t mycluster:web /dev/drbd1 +It appears to contain an existing filesystem (ext4) +This will destroy any data on /dev/drbd1 Are you sure you want to proceed? [y/n]y Device: /dev/drbd1 -Blocksize: 4096 -Device Size 0.97 GB (253935 blocks) -Filesystem Size: 0.97 GB (253932 blocks) +Block size: 4096 +Device size: 1.00 GB (262127 blocks) +Filesystem size: 1.00 GB (262124 blocks) Journals: 2 -Resource Groups: 4 -Locking Protocol: "lock_dlm" -Lock Table: "mycluster" -UUID: ed293a02-9eee-3fa3-ed1c-435ef1fd0116 +Resource groups: 3 +Locking protocol: "lock_dlm" +Lock table: "mycluster:web" +UUID: b2b30e6c-8890-33fa-a1ba-3c70edd4b5f0 ----- -ifdef::pcs[] -[source,C] ----- -# pcs cluster cib dlm_cfg -# pcs -f dlm_cfg resource create dlm ocf:pacemaker:controld op monitor interval=60s -# pcs -f dlm_cfg resource clone dlm clone-max=2 clone-node-max=1 -# pcs -f dlm_cfg resource show - ClusterIP (ocf::heartbeat:IPaddr2) Started - WebSite (ocf::heartbeat:apache) Stopped - Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-2 ] - Slaves: [ pcmk-1 ] - WebFS (ocf::heartbeat:Filesystem) Stopped - Clone Set: dlm-clone [dlm] - Stopped: [ dlm:0 dlm:1 ] -# pcs cluster push cib dlm_cfg -CIB updated -# pcs status +The `mkfs.gfs2` command required a number of additional parameters: -Last updated: Fri Sep 14 12:54:50 2012 -Last change: Fri Sep 14 12:54:43 2012 via cibadmin on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -7 Resources configured. +* `-p lock_dlm` specifies that we want to use the +kernel's DLM. -Online: [ pcmk-1 pcmk-2 ] - -Full list of resources: - - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf::heartbeat:apache): Stopped - Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-2 ] - Slaves: [ pcmk-1 ] - WebFS (ocf::heartbeat:Filesystem): Stopped - Clone Set: dlm-clone [dlm] - Started: [ pcmk-1 pcmk-2 ] ----- -endif::[] - -ifdef::crmsh[] -[source,C] ------ -# crm -crm(live)# cib new dlm -INFO: dlm shadow CIB created -crm(dlm)# configure primitive dlm ocf:pacemaker:controld \ - op monitor interval=60s -crm(dlm)# configure clone dlm_clone dlm meta clone-max=2 clone-node-max=1 -crm(dlm)# configure show -node $id="1702537408" pcmk-1 \ - attributes standby="off" -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -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="ext4" \ - meta target-role="Stopped" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -primitive dlm ocf:pacemaker:controld \ - op monitor interval="60s" -ms WebDataClone WebData \ - meta master-max="1" master-node-max="1" clone-max="2" clone-node-max="1" notify="true" -clone dlm_clone dlm \ - meta clone-max="2" clone-node-max="1" -location prefer-pcmk-1 WebSite 50: pcmk-1 -colocation WebSite-with-WebFS inf: WebSite WebFS -colocation fs_on_drbd inf: WebFS WebDataClone:Master -colocation website-with-ip inf: WebSite ClusterIP -order WebFS-after-WebData inf: WebDataClone:promote WebFS:start -order WebSite-after-WebFS inf: WebFS WebSite -order apache-after-ip inf: ClusterIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" \ - last-lrm-refresh="1333446866" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" -crm(dlm)# cib commit dlm -INFO: commited 'dlm' shadow CIB to the cluster -crm(dlm)# quit -bye -# crm_mon -1 -============ -Last updated: Wed Apr 4 01:15:11 2012 -Last change: Wed Apr 4 00:50:11 2012 via crmd on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -7 Resources configured. -============ - -Online: [ pcmk-1 pcmk-2 ] +* `-j 2` indicates that the filesystem should reserve enough +space for two journals (one for each node that will access the filesystem). - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 - Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-1 ] - Slaves: [ pcmk-2 ] - Clone Set: dlm_clone [dlm] - Started: [ pcmk-1 pcmk-2 ] ------ -endif::[] +* `-t mycluster:web` specifies the lock table name. The format for +this field is +pass:[clustername:fsname]+. For ++pass:[clustername]+, we need to use the same +value we specified originally with `pcs cluster setup --name` (which is also +the value of *cluster_name* in +/etc/corosync/corosync.conf+). +If you are unsure what your cluster name is, you can look in ++/etc/corosync/corosync.conf+ or execute the command +`pcs cluster corosync pcmk-1 | grep cluster_name`. -Then (re)populate the new filesystem with data (web pages). For now we'll -create another variation on our home page. +Now we can (re-)populate the new filesystem with data +(web pages). We'll create yet another variation on our home page. -[source,C] ----- -# mount /dev/drbd1 /mnt/ -# cat <<-END >/mnt/index.html +[root@pcmk-2 ~]# mount /dev/drbd1 /mnt +[root@pcmk-2 ~]# cat <<-END >/mnt/index.html My Test Site - GFS2 END -# umount /dev/drbd1 -# drbdadm verify wwwdata +[root@pcmk-2 ~]# umount /dev/drbd1 +[root@pcmk-2 ~]# drbdadm verify wwwdata ----- == Reconfigure the Cluster for GFS2 == +With the WebFS resource stopped, let's update the configuration. -ifdef::pcs[] - -With the WebFS resource stopped, lets update the configuration. - -[source,C] ---- -# pcs resource show WebFS -Resource: WebFS - device: /dev/drbd/by-res/wwwdata - directory: /var/www/html - fstype: ext4 - target-role: Stopped +[root@pcmk-1 ~]# pcs resource show WebFS + Resource: WebFS (class=ocf provider=heartbeat type=Filesystem) + Attributes: device=/dev/drbd1 directory=/var/www/html fstype=ext4 + Meta Attrs: target-role=Stopped + Operations: start interval=0s timeout=60 (WebFS-start-timeout-60) + stop interval=0s timeout=60 (WebFS-stop-timeout-60) + monitor interval=20 timeout=40 (WebFS-monitor-interval-20) ---- -The fstype option needs to be updated to gfs2 instead of ext4. +The fstype option needs to be updated to *gfs2* instead of *ext4*. -[source,C] ---- -# pcs resource update WebFS fstype=gfs2 -# pcs resource show WebFS -Resource: WebFS - device: /dev/drbd/by-res/wwwdata - directory: /var/www/html - fstype: gfs2 - target-role: Stopped -CIB updated +[root@pcmk-1 ~]# pcs resource update WebFS fstype=gfs2 +[root@pcmk-1 ~]# pcs resource show WebFS + Resource: WebFS (class=ocf provider=heartbeat type=Filesystem) + Attributes: device=/dev/drbd1 directory=/var/www/html fstype=gfs2 + Meta Attrs: target-role=Stopped + Operations: start interval=0s timeout=60 (WebFS-start-timeout-60) + stop interval=0s timeout=60 (WebFS-stop-timeout-60) + monitor interval=20 timeout=40 (WebFS-monitor-interval-20) ---- -endif::[] - -ifdef::crmsh[] -[source,C] ------ -# crm -crm(live) # cib new GFS2 -INFO: GFS2 shadow CIB created -crm(GFS2) # configure delete WebFS -crm(GFS2) # configure primitive WebFS ocf:heartbeat:Filesystem params device="/dev/drbd/by-res/wwwdata" directory="/var/www/html" fstype="gfs2" ------ - -Now that we've recreated the resource, we also need to recreate all the -constraints that used it. This is because the shell will automatically -remove any constraints that referenced WebFS. - -[source,C] ------ -crm(GFS2) # configure colocation WebSite-with-WebFS inf: WebSite WebFS -crm(GFS2) # configure colocation fs_on_drbd inf: WebFS WebDataClone:Master -crm(GFS2) # configure order WebFS-after-WebData inf: WebDataClone:promote WebFS:start -crm(GFS2) # configure order WebSite-after-WebFS inf: WebFS WebSite -crm(GFS2) # configure show -node 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" \ - op monitor interval="30s" -ms WebDataClone WebData \ - meta master-max="1" master-node-max="1" clone-max="2" clone-node-max="1" notify="true" -colocation WebSite-with-WebFS inf: WebSite WebFS -colocation fs_on_drbd inf: WebFS WebDataClone:Master -colocation website-with-ip inf: WebSite ClusterIP -order WebFS-after-WebData inf: WebDataClone:promote WebFS:start -order WebSite-after-WebFS inf: WebFS WebSite -order apache-after-ip inf: ClusterIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.5-bdd89e69ba545404d02445be1f3d72e6a203ba2f" \ - cluster-infrastructure="openais" \ - expected-quorum-votes="2" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" ------ - -Review the configuration before uploading it to the cluster, quitting the -shell and watching the cluster's response - -[source,C] ------ -crm(GFS2) # cib commit GFS2 -INFO: commited 'GFS2' shadow CIB to the cluster -crm(GFS2) # quit -bye -# crm_mon -============ -Last updated: Thu Sep 3 20:49:54 2009 -Stack: openais -Current DC: pcmk-2 - partition with quorum -Version: 1.1.5-bdd89e69ba545404d02445be1f3d72e6a203ba2f -2 Nodes configured, 2 expected votes -6 Resources configured. -============ -Online: [ pcmk-1 pcmk-2 ] - -WebSite (ocf::heartbeat:apache): Started pcmk-2 -Master/Slave Set: WebDataClone - Masters: [ pcmk-1 ] - Slaves: [ pcmk-2 ] -ClusterIP (ocf::heartbeat:IPaddr): Started pcmk-2WebFS (ocf::heartbeat:Filesystem): Started pcmk-1 ------ -endif::[] - -== Reconfigure Pacemaker for Active/Active == - -Almost everything is in place. Recent versions of DRBD are capable of -operating in Primary/Primary mode and the filesystem we're using is -cluster aware. All we need to do now is reconfigure the cluster to take -advantage of this. - -ifdef::pcs[] -This will involve a number of changes, so we'll want work with a -local cib file. - -[source,C] +GFS2 requires that DLM be running, so we also need to set up new colocation +and ordering constraints for it: ---- -# pcs cluster cib active_cfg +[root@pcmk-1 ~]# pcs constraint colocation add WebFS with dlm-clone INFINITY +[root@pcmk-1 ~]# pcs constraint order dlm-clone then WebFS ---- -endif::[] -ifdef::crmsh[] -This will involve a number of changes, so we'll again use interactive -mode. - -[source,C] ------ -# crm -# cib new active ------ -endif::[] +== Clone the IP address == There's no point making the services active on both locations if we can't -reach them, so lets first clone the IP address. Cloned IPaddr2 resources -use an iptables rule to ensure that each request only gets processed by one of -the two clone instances. The additional meta options tell the cluster how -many instances of the clone we want (one "request bucket" for each node) -and that if all other nodes fail, then the remaining node should hold all -of them. Otherwise the requests would be simply discarded. +reach them both, so let's clone the IP address. +The *IPaddr2* resource agent has built-in intelligence for when it is configured +as a clone. It will utilize a multicast MAC address to have the local switch +send the relevant packets to all nodes in the cluster, together with *iptables +clusterip* rules on the nodes so that any given packet will be grabbed by +exactly one node. This will give us a simple but effective form of +load-balancing requests between our two nodes. -ifdef::pcs[] +Let's start a new config, and clone our IP: ---- -# pcs -f active_cfg resource clone ClusterIP \ - globally-unique=true clone-max=2 clone-node-max=2 +[root@pcmk-1 ~]# pcs cluster cib loadbalance_cfg +[root@pcmk-1 ~]# pcs -f loadbalance_cfg resource clone ClusterIP \ + clone-max=2 clone-node-max=2 globally-unique=true ---- -Notice when the ClusterIP becomes a clone, the constraints +* `clone-max=2` tells the resource agent to split packets this many ways. This +should equal the number of nodes that can host the IP. +* `clone-node-max=2` says that one node can run up to 2 instances +of the clone. This should also equal the number of nodes that can +host the IP, so that if any node goes down, another node can take over +the failed node's "request bucket". Otherwise, requests intended for +the failed node would be discarded. +* `globally-unique=true` tells the cluster that one clone isn't identical +to another (each handles a different "bucket"). This also tells the resource +agent to insert *iptables* rules so each host only processes packets in its +bucket(s). + +Notice that when the ClusterIP becomes a clone, the constraints referencing ClusterIP now reference the clone. This is done automatically by pcs. -endif::[] - -ifdef::pcs[] -[source,C] ---- -# pcs -f active_cfg constraint +[root@pcmk-1 ~]# pcs -f loadbalance_cfg constraint Location Constraints: Ordering Constraints: - start ClusterIP-clone then start WebSite - WebFS then WebSite - promote WebDataClone then start WebFS + start ClusterIP-clone then start WebSite (kind:Mandatory) + promote WebDataClone then start WebFS (kind:Mandatory) + start WebFS then start WebSite (kind:Mandatory) + start dlm-clone then start WebFS (kind:Mandatory) Colocation Constraints: - WebSite with ClusterIP-clone - WebFS with WebDataClone (with-rsc-role:Master) - WebSite with WebFS + WebSite with ClusterIP-clone (score:INFINITY) + WebFS with WebDataClone (score:INFINITY) (with-rsc-role:Master) + WebSite with WebFS (score:INFINITY) + WebFS with dlm-clone (score:INFINITY) ---- -endif::[] - -ifdef::crmsh[] -[source,C] ------ -# configure clone WebIP ClusterIP \ - meta globally-unique="true" clone-max="2" clone-node-max="2" ------ -endif::[] -Now we must tell the ClusterIP how to decide which requests are -processed by which hosts. To do this we must specify the -clusterip_hash parameter. +Now we must tell the resource how to decide which requests are +processed by which hosts. To do this, we specify the *clusterip_hash* parameter. +The value of *sourceip* means that the source IP address of incoming packets +will be hashed; each node will process a certain range of hashes. -ifdef::pcs[] -[source,C] ---- -# pcs -f active_cfg resource update ClusterIP clusterip_hash=sourceip +[root@pcmk-1 ~]# pcs -f loadbalance_cfg resource update ClusterIP clusterip_hash=sourceip ---- -endif::[] -ifdef::crmsh[] -Open the ClusterIP resource - -[source,C] ------ -# configure edit ClusterIP +Load our configuration to the cluster, and see how it responds. ----- +[root@pcmk-1 ~]# pcs cluster cib-push loadbalance_cfg +CIB updated +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Sat Dec 20 22:05:48 2014 +Last change: Sat Dec 20 22:05:34 2014 +Stack: corosync +Current DC: pcmk-1 (1) - partition with quorum +Version: 1.1.12-a9c8177 +2 Nodes configured +9 Resources configured -And add the following to the params line -..... -clusterip_hash="sourceip" -..... +Online: [ pcmk-1 pcmk-2 ] -So that the complete definition looks like: +Full list of resources: -..... -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.101" cidr_netmask="32" clusterip_hash="sourceip" \ - op monitor interval="30s" -..... + WebSite (ocf::heartbeat:apache): Stopped + Master/Slave Set: WebDataClone [WebData] + Masters: [ pcmk-1 ] + Slaves: [ pcmk-2 ] + WebFS (ocf::heartbeat:Filesystem): Stopped + ipmi-fencing (stonith:fence_ipmilan): Started pcmk-1 + Clone Set: dlm-clone [dlm] + Started: [ pcmk-1 pcmk-2 ] + Clone Set: ClusterIP-clone [ClusterIP] (unique) + ClusterIP:0 (ocf::heartbeat:IPaddr2): Started pcmk-1 + ClusterIP:1 (ocf::heartbeat:IPaddr2): Started pcmk-2 -Here is the full transcript +PCSD Status: + pcmk-1: Online + pcmk-2: Online -[source,C] ------ -# crm crm(live) -# cib new active -INFO: active shadow CIB created -crm(active) # configure clone WebIP ClusterIP \ - meta globally-unique="true" clone-max="2" clone-node-max="2" -crm(active) # 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" -ms WebDataClone WebData \ - meta master-max="1" master-node-max="1" clone-max="2" clone-node-max="1" notify="true" -clone WebIP ClusterIP \ - meta globally-unique="true" clone-max="2" clone-node-max="2" -colocation WebSite-with-WebFS inf: WebSite WebFS -colocation fs_on_drbd inf: WebFS WebDataClone:Master -colocation website-with-ip inf: WebSite WebIPorder WebFS-after-WebData inf: WebDataClone:promote WebFS:start -order WebSite-after-WebFS inf: WebFS WebSiteorder apache-after-ip inf: WebIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.5-bdd89e69ba545404d02445be1f3d72e6a203ba2f" \ - cluster-infrastructure="openais" \ - expected-quorum-votes="2" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ----- -Notice how any constraints that referenced ClusterIP have been updated -to use WebIP instead. This is an additional benefit of using the crm -shell. -endif::[] +If desired, you can demonstrate that all request buckets are working +by using a tool such as `arping` from several source hosts +to see which host responds to each. -Next we need to convert the filesystem and Apache resources into -clones. +== Clone the Filesystem and Apache Resources == -ifdef::pcs[] +Now that we have a cluster filesystem ready to go, +and our nodes can load-balance requests to a shared IP address, +we can configure the cluster so both nodes mount the filesystem +and respond to web requests. + +Clone the filesystem and Apache resources in a new configuration. Notice how pcs automatically updates the relevant constraints again. -[source,C] ---- -# pcs -f active_cfg resource clone WebFS -# pcs -f active_cfg resource clone WebSite -# pcs -f active_cfg constraint +[root@pcmk-1 ~]# pcs cluster cib active_cfg +[root@pcmk-1 ~]# pcs -f active_cfg resource clone WebFS +[root@pcmk-1 ~]# pcs -f active_cfg resource clone WebSite +[root@pcmk-1 ~]# pcs -f active_cfg constraint Location Constraints: Ordering Constraints: - start ClusterIP-clone then start WebSite-clone - WebFS-clone then WebSite-clone - promote WebDataClone then start WebFS-clone + start ClusterIP-clone then start WebSite-clone (kind:Mandatory) + promote WebDataClone then start WebFS-clone (kind:Mandatory) + start WebFS-clone then start WebSite-clone (kind:Mandatory) + start dlm-clone then start WebFS-clone (kind:Mandatory) Colocation Constraints: - WebSite-clone with ClusterIP-clone - WebFS-clone with WebDataClone (with-rsc-role:Master) - WebSite-clone with WebFS-clone + WebSite-clone with ClusterIP-clone (score:INFINITY) + WebFS-clone with WebDataClone (score:INFINITY) (with-rsc-role:Master) + WebSite-clone with WebFS-clone (score:INFINITY) + WebFS-clone with dlm-clone (score:INFINITY) ---- -endif::[] -ifdef::crmsh[] -Again, the shell will automatically update any relevant -constraints. +Tell the cluster that it is now allowed to promote both instances to be DRBD +Primary (aka. master). -[source,C] ----- -crm(active) # configure clone WebFSClone WebFS -crm(active) # configure clone WebSiteClone WebSite +[root@pcmk-1 ~]# pcs -f active_cfg resource update WebDataClone master-max=2 ----- -endif::[] - -The last step is to tell the cluster that it is now allowed to promote -both instances to be Primary (aka. Master). -ifdef::pcs[] -[source,C] ------ -# pcs -f active_cfg resource update WebDataClone master-max=2 ------ -endif::[] - -ifdef::crmsh[] -[source,C] ------ -crm(active) # configure edit WebDataClone +Finally, load our configuration to the cluster, and re-enable the WebFS resource +(which we disabled earlier). ----- - -Change master-max to 2 - -[source,C] ------ -crm(active) # configure show -node 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" -ms WebDataClone WebData \ - meta master-max="2" master-node-max="1" clone-max="2" clone-node-max="1" notify="true" -clone WebFSClone WebFSclone WebIP ClusterIP \ - meta globally-unique="true" clone-max="2" clone-node-max="2" -clone WebSiteClone WebSitecolocation 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="false" \ - no-quorum-policy="ignore" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" ------ -endif::[] - -Review the configuration before uploading it to the cluster, quitting the -shell and watching the cluster's response - -ifdef::pcs[] -[source,C] ------ -# pcs cluster push cib active_cfg -# pcs resource enable WebFS +[root@pcmk-1 ~]# pcs cluster cib-push active_cfg +CIB updated +[root@pcmk-1 ~]# pcs resource enable WebFS ----- -After all the processes are started the status should look -similar to this. - -[source,C] +After all the processes are started, the status should look similar to this. ----- -# pcs resource +[root@pcmk-1 ~]# pcs resource Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-2 pcmk-1 ] + Masters: [ pcmk-1 pcmk-2 ] Clone Set: dlm-clone [dlm] - Started: [ pcmk-2 pcmk-1 ] + Started: [ pcmk-1 pcmk-2 ] Clone Set: ClusterIP-clone [ClusterIP] (unique) - ClusterIP:0 (ocf::heartbeat:IPaddr2) Started - ClusterIP:1 (ocf::heartbeat:IPaddr2) Started + ClusterIP:0 (ocf::heartbeat:IPaddr2): Started + ClusterIP:1 (ocf::heartbeat:IPaddr2): Started Clone Set: WebFS-clone [WebFS] Started: [ pcmk-1 pcmk-2 ] Clone Set: WebSite-clone [WebSite] Started: [ pcmk-1 pcmk-2 ] ----- -endif::[] - -ifdef::crmsh[] -[source,C] ------ -crm(active) # cib commit active -INFO: commited 'active' shadow CIB to the cluster -crm(active) # quit -bye -# crm_mon -============ -Last updated: Thu Sep 3 21:37:27 2009 -Stack: openais -Current DC: pcmk-2 - partition with quorum -Version: 1.1.5-bdd89e69ba545404d02445be1f3d72e6a203ba2f -2 Nodes configured, 2 expected votes -6 Resources configured. -============ - -Online: [ pcmk-1 pcmk-2 ] -Master/Slave Set: WebDataClone - Masters: [ pcmk-1 pcmk-2 ] -Clone Set: WebIP Started: [ pcmk-1 pcmk-2 ] -Clone Set: WebFSClone Started: [ pcmk-1 pcmk-2 ] -Clone Set: WebSiteClone Started: [ pcmk-1 pcmk-2 ] -Clone Set: dlm_clone Started: [ pcmk-1 pcmk-2 ] ------ -endif::[] +== Test Failover == -=== Testing Recovery === +Testing failover is left as an exercise for the reader. +For example, you can put one node into standby mode, +use `pcs status` to confirm that its ClusterIP clone was +moved to the other node, and use `arping` to verify that +packets are not being lost from any source host. [NOTE] -======= -TODO: Put one node into standby to demonstrate failover -======= +==== +You may find that when a failed node rejoins the cluster, +both ClusterIP clones stay on one node, due to the +resource stickiness. While this works fine, it effectively eliminates +load-balancing and returns the cluster to an active-passive setup again. +You can avoid this by disabling stickiness for the IP address resource: +---- +[root@pcmk-1 ~]# pcs resource meta ClusterIP resource-stickiness=0 +---- +==== diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Active-Passive.txt b/doc/Clusters_from_Scratch/en-US/Ch-Active-Passive.txt index 7da8fca2d9..eae49ea616 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Active-Passive.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Active-Passive.txt @@ -1,683 +1,425 @@ -= Creating an Active/Passive Cluster = += Create an Active/Passive Cluster = -== Exploring the Existing Configuration == +== Explore the Existing Configuration == When Pacemaker starts up, it automatically records the number and details -of the nodes in the cluster as well as which stack is being used and the +of the nodes in the cluster, as well as which stack is being used and the version of Pacemaker being used. -This is what the base configuration should look like. +The first few lines of output should look like this: -ifdef::pcs[] -[source,C] ---- -# pcs status -Last updated: Fri Sep 14 10:12:01 2012 -Last change: Fri Sep 14 09:51:55 2012 via crmd on pcmk-2 +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +WARNING: no stonith devices and stonith-enabled is not false +Last updated: Tue Dec 16 16:15:29 2014 +Last change: Tue Dec 16 15:49:47 2014 Stack: corosync -Current DC: pcmk-1 (1) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -0 Resources configured. +Current DC: pcmk-2 (2) - partition with quorum +Version: 1.1.12-a9c8177 +2 Nodes configured +0 Resources configured -Online: [ pcmk-1 pcmk-2 ] -Full list of resources: ----- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" +Online: [ pcmk-1 pcmk-2 ] ---- -endif::[] - -ifdef::pcs[] -For those that are not of afraid of XML, you can see the raw cluster -configuration and status by using the +pcs cluster cib+ command. +For those who are not of afraid of XML, you can see the raw cluster +configuration and status by using the `pcs cluster cib` command. .The last XML you'll see in this document ====== -[source,C] ---- -# pcs cluster cib +[root@pcmk-1 ~]# pcs cluster cib ---- [source,XML] ---- - + - + + + - - + + - + + - + + ---- ====== -endif::[] - -ifdef::crmsh[] -For those that are not of afraid of XML, you can see the raw configuration by appending "xml" to the previous command. -.The last XML you'll see in this document -====== -[source,C] ----- -# crm configure show xml ----- -[source,XML] ----- - - - - - - - - - - - - - - - - - ----- -====== -endif::[] - -Before we make any changes, its a good idea to check the validity of +Before we make any changes, it's a good idea to check the validity of the configuration. -[source,C] ---- -# crm_verify -L -V +[root@pcmk-1 ~]# crm_verify -L -V error: unpack_resources: Resource start-up disabled since no STONITH resources have been defined error: unpack_resources: Either configure some or disable STONITH with the stonith-enabled option error: unpack_resources: NOTE: Clusters with shared data need STONITH to ensure data integrity Errors found during check: config not valid - -V may provide more details ---- As you can see, the tool has found some errors. -In order to guarantee the safety of your data +In order to guarantee the safety of your data, footnote:[If the data is corrupt, there is little point in continuing to make it available] -, the default for STONITH +the default for STONITH footnote:[A common node fencing mechanism. Used to ensure data integrity by powering off "bad" nodes] -in Pacemaker is +enabled+. However it also knows when no STONITH configuration has been +in Pacemaker is *enabled*. However, it also knows when no STONITH configuration has been supplied and reports this as a problem (since the cluster would not be able to make progress if a situation requiring node fencing arose). -For now, we will disable this feature and configure it later in the -Configuring STONITH section. It is important to note that the use of -STONITH is highly encouraged, turning it off tells the cluster to -simply pretend that failed nodes are safely powered off. Some vendors -will even refuse to support clusters that have it disabled. +We will disable this feature for now and configure it later. -To disable STONITH, we set the _stonith-enabled_ cluster option to -false. +To disable STONITH, set the *stonith-enabled* cluster option to +false: -ifdef::pcs[] -[source,C] ---- -# pcs property set stonith-enabled=false -# crm_verify -L +[root@pcmk-1 ~]# pcs property set stonith-enabled=false +[root@pcmk-1 ~]# crm_verify -L ---- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# crm configure property stonith-enabled=false -# crm_verify -L ----- -endif::[] With the new cluster option set, the configuration is now valid. [WARNING] ========= - -The use of stonith-enabled=false is completely inappropriate for a -production cluster. We use it here to defer the discussion of its -configuration which can differ widely from one installation to the -next. See <<_what_is_stonith>> for information on why STONITH is important +The use of `stonith-enabled=false` is completely inappropriate for a +production cluster. It tells the cluster to simply pretend that failed nodes +are safely powered off. Some vendors will refuse to support clusters that have +STONITH disabled. + +We disable STONITH here only to defer the discussion of its +configuration, which can differ widely from one installation to the +next. See <<_what_is_stonith>> for information on why STONITH is important and details on how to configure it. - ========= -== Adding a Resource == +== Add a Resource == -The first thing we should do is configure an IP address. Regardless of -where the cluster service(s) are running, we need a consistent address -to contact them on. Here I will choose and add 192.168.122.120 as the -floating address, give it the imaginative name ClusterIP and tell the -cluster to check that its running every 30 seconds. +Our first resource will be a unique IP address that the cluster can bring up on +either node. Regardless of where any cluster service(s) are running, end +users need a consistent address to contact them on. Here, I will choose +192.168.122.120 as the floating address, give it the imaginative name ClusterIP +and tell the cluster to check whether it is running every 30 seconds. - -[IMPORTANT] +[WARNING] =========== -The chosen address must not be one already associated with -a physical node +The chosen address must not already be in use on the network. +Do not reuse an IP address one of the nodes already has configured. =========== -//// -No syntax highlighting here to avoid line munging with source,C -//// -ifdef::pcs[] ---- -# pcs resource create ClusterIP ocf:heartbeat:IPaddr2 \ - ip=192.168.0.120 cidr_netmask=32 op monitor interval=30s +[root@pcmk-1 ~]# pcs resource create ClusterIP ocf:heartbeat:IPaddr2 \ + ip=192.168.122.120 cidr_netmask=32 op monitor interval=30s ---- -endif::[] -ifdef::crmsh[] ----- -# crm configure primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip=192.168.122.120 cidr_netmask=32 \ - op monitor interval=30s ----- -endif::[] +Another important piece of information here is *ocf:heartbeat:IPaddr2*. +This tells Pacemaker three things about the resource you want to add: + +* The first field (*ocf* in this case) is the standard to which the resource +script conforms and where to find it. -The other important piece of information here is ocf:heartbeat:IPaddr2. +* The second field (*heartbeat* in this case) is standard-specific; for OCF +resources, it tells the cluster which OCF namespace the resource script is in. -This tells Pacemaker three things about the resource you want to -add. The first field, ocf, is the standard to which the resource -script conforms to and where to find it. The second field is specific -to OCF resources and tells the cluster which namespace to find the -resource script in, in this case heartbeat. The last field indicates -the name of the resource script. +* The third field (*IPaddr2* in this case) is the name of the resource script. -ifdef::pcs[] -To obtain a list of the available resource standards (the ocf part of -ocf:heartbeat:IPaddr2), run +To obtain a list of the available resource standards (the *ocf* part of +*ocf:heartbeat:IPaddr2*), run: -[source,C] ---- -# pcs resource standards +[root@pcmk-1 ~]# pcs resource standards ocf lsb service systemd stonith ---- -To obtain a list of the available ocf resource providers (the heartbeat -part of ocf:heartbeat:IPaddr2), run +To obtain a list of the available OCF resource providers (the *heartbeat* +part of *ocf:heartbeat:IPaddr2*), run: -[source,C] ---- -# pcs resource providers +[root@pcmk-1 ~]# pcs resource providers heartbeat -linbit pacemaker -redhat ---- Finally, if you want to see all the resource agents available for -a specific ocf provider (the IPaddr2 part of ocf:heartbeat:IPaddr2), run +a specific OCF provider (the *IPaddr2* part of *ocf:heartbeat:IPaddr2*), run: -[source,C] ---- -# pcs resource agents ocf:heartbeat +[root@pcmk-1 ~]# pcs resource agents ocf:heartbeat AoEtarget AudibleAlarm CTDB ClusterMon Delay Dummy . . (skipping lots of resources to save space) . IPaddr2 . . . -symlink -syslog-ng tomcat +varnish vmware +zabbixserver ---- -endif::[] -ifdef::crmsh[] +Now, verify that the IP resource has been added, and display the cluster's +status to see that it is now active: -To obtain a list of the available resource classes, run - -[source,C] ----- -# crm ra classes -heartbeat -lsb -ocf / heartbeat pacemaker -stonith ---- - -To then find all the OCF resource agents provided by Pacemaker and -Heartbeat, run - -[source,C] ----- -# crm ra list ocf pacemaker -ClusterMon Dummy HealthCPU HealthSMART Stateful SysInfo -SystemHealth controld o2cb ping pingd -# crm ra list ocf heartbeat -AoEtarget AudibleAlarm CTDB ClusterMon -Delay Dummy EvmsSCC Evmsd -Filesystem ICP IPaddr IPaddr2 -IPsrcaddr IPv6addr LVM LinuxSCSI -MailTo ManageRAID ManageVE Pure-FTPd -Raid1 Route SAPDatabase SAPInstance -SendArp ServeRAID SphinxSearchDaemon Squid -Stateful SysInfo VIPArip VirtualDomain -WAS WAS6 WinPopup Xen -Xinetd anything apache conntrackd -db2 drbd eDir88 ethmonitor -exportfs fio iSCSILogicalUnit iSCSITarget -ids iscsi jboss ldirectord -lxc mysql mysql-proxy nfsserver -nginx oracle oralsnr pgsql -pingd portblock postfix proftpd -rsyncd scsi2reservation sfex symlink -syslog-ng tomcat vmware ----- -endif::[] - -Now verify that the IP resource has been added and display the cluster's -status to see that it is now active. - -ifdef::pcs[] -[source,C] ----- -# pcs status - -Last updated: Fri Sep 14 10:17:00 2012 -Last change: Fri Sep 14 10:15:48 2012 via cibadmin on pcmk-1 +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Tue Dec 16 17:44:40 2014 +Last change: Tue Dec 16 17:44:26 2014 Stack: corosync Current DC: pcmk-1 (1) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -1 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +1 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 ----- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" -# crm_mon -1 -============ -Last updated: Tue Apr 3 09:56:50 2012 -Last change: Tue Apr 3 09:54:37 2012 via cibadmin on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -1 Resources configured. -============ + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 -Online: [ pcmk-1 pcmk-2 ] +PCSD Status: + pcmk-1: Online + pcmk-2: Online - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -endif::[] == Perform a Failover == -Being a high-availability cluster, we should test failover of our new -resource before moving on. +Since our ultimate goal is high availability, we should test failover of +our new resource before moving on. First, find the node on which the IP address is running. -ifdef::pcs[] -[source,C] ---- -# pcs status - -Last updated: Fri Sep 14 10:17:00 2012 -Last change: Fri Sep 14 10:15:48 2012 via cibadmin on pcmk-1 +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Tue Dec 16 17:44:40 2014 +Last change: Tue Dec 16 17:44:26 2014 Stack: corosync Current DC: pcmk-1 (1) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -1 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +1 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 ---- -endif::[] -ifdef::crmsh[] -[source,C] +You can see that the status of the *ClusterIP* resource +is *Started* on a particular node (in this example, *pcmk-1*). +Shut down Pacemaker and Corosync on that machine to trigger a failover. + ---- -# crm resource status ClusterIP -resource ClusterIP is running on: pcmk-1 +[root@pcmk-1 ~]# pcs cluster stop pcmk-1 +Stopping Cluster... ---- -endif::[] -Shut down Pacemaker and Corosync on that machine. +[NOTE] +====== +A cluster command such as +pcs cluster stop pass:[nodename]+ can be run +from any node in the cluster, not just the affected node. +====== -ifdef::pcs[] -[source,C] +Verify that pacemaker and corosync are no longer running: ---- -#pcs cluster stop pcmk-1 -Stopping Cluster... +[root@pcmk-1 ~]# pcs status +Error: cluster is not currently running on this node ---- -Once Corosync is no longer running, go to the other node and check the -cluster status. +Go to the other node, and check the cluster status. -[source,C] ---- -# pcs status - -Last updated: Fri Sep 14 10:31:01 2012 -Last change: Fri Sep 14 10:15:48 2012 via cibadmin on pcmk-1 +[root@pcmk-2 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 10:30:56 2014 +Last change: Tue Dec 16 17:44:26 2014 Stack: corosync -Current DC: pcmk-2 (2) - partition WITHOUT quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -1 Resources configured. +Current DC: pcmk-2 (2) - partition with quorum +Version: 1.1.12-a9c8177 +2 Nodes configured +1 Resources configured + Online: [ pcmk-2 ] OFFLINE: [ pcmk-1 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Stopped ----- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# ssh pcmk-1 -- service pacemaker stop -# ssh pcmk-1 -- service corosync stop ----- + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 -Once Corosync is no longer running, go to the other node and check the -cluster status with crm_mon. +PCSD Status: + pcmk-1: Online + pcmk-2: Online -[source,C] ----- -# crm_mon -1 -============ -Last updated: Tue Apr 3 10:01:28 2012 -Last change: Tue Apr 3 09:54:39 2012 via cibadmin on pcmk-1 -Stack: corosync -Current DC: pcmk-2 (1719314624) - partition WITHOUT quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -1 Resources configured. -============ - -Online: [ pcmk-2 ] -OFFLINE: [ pcmk-1 ] +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -endif::[] -There are three things to notice about the cluster's current -state. The first is that, as expected, +pcmk-1+ is now offline. However -we can also see that +ClusterIP+ isn't running anywhere! +Notice that *pcmk-1* is *OFFLINE* for cluster purposes (its *PCSD* is still +*Online*, allowing it to receive `pcs` commands, but it is not participating in +the cluster). +Also notice that *ClusterIP* is now running on pcmk-2 -- failover happened +automatically, and no errors are reported. -=== Quorum and Two-Node Clusters === - -This is because the cluster no longer has quorum, as can be seen by -the text "partition WITHOUT quorum" in the status output. In order -to reduce the possibility of data corruption, Pacemaker's default -behavior is to stop all resources if the cluster does not have quorum. - -A cluster is said to have quorum when more than half the known or -expected nodes are online, or for the mathematically inclined, -whenever the following equation is true: - +[IMPORTANT] +.Quorum +==== +If a cluster splits into two (or more) groups of nodes that can no longer +communicate with each other (aka. _partitions_), _quorum_ is used to prevent +resources from starting on more nodes than desired, which would risk +data corruption. + +A cluster has quorum when more than half of all known nodes are online in +the same partition, or for the mathematically inclined, whenever the following +equation is true: .... total_nodes < 2 * active_nodes .... -Therefore a two-node cluster only has quorum when both nodes are -running, which is no longer the case for our cluster. This would -normally make the creation of a two-node cluster pointless -footnote:[Actually some would argue that two-node clusters are always pointless, but that is an argument for another time] -, however it is possible to control how Pacemaker behaves when quorum -is lost. In particular, we can tell the cluster to simply ignore -quorum altogether. - -ifdef::pcs[] -[source,C] ----- -# pcs property set no-quorum-policy=ignore -# pcs property -dc-version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -cluster-infrastructure: corosync -stonith-enabled: false -no-quorum-policy: ignore ----- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# crm configure property no-quorum-policy=ignore -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" ----- -endif::[] - -After a few moments, the cluster will start the IP address on the -remaining node. Note that the cluster still does not have quorum. - -ifdef::pcs[] -[source,C] ----- -# pcs status -Last updated: Fri Sep 14 10:38:11 2012 -Last change: Fri Sep 14 10:37:53 2012 via cibadmin on pcmk-2 -Stack: corosync -Current DC: pcmk-2 (2) - partition WITHOUT quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -1 Resources configured. - -Online: [ pcmk-2 ] -OFFLINE: [ pcmk-1 ] - -Full list of resources: - - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 ----- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# crm_mon -1 -============ -Last updated: Tue Apr 3 10:02:46 2012 -Last change: Tue Apr 3 10:02:08 2012 via cibadmin on pcmk-2 -Stack: corosync -Current DC: pcmk-2 (1719314624) - partition WITHOUT quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -1 Resources configured. -============ - -Online: [ pcmk-2 ] -OFFLINE: [ pcmk-1 ] - - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 ----- -endif::[] - -Now simulate node recovery by restarting the cluster stack on +pcmk-1+ and -check the cluster's status. Note, if you get an authentication error with -the 'pcs cluster start pcmk-1' command, you must authenticate on the node -using the 'pcs cluster auth pcmk pcmk-1 pcmk-2' command discussed earlier. - -ifdef::pcs[] -[source,C] ----- -# pcs cluster start pcmk-1 -Starting Cluster... -# pcs status - -Last updated: Fri Sep 14 10:42:56 2012 -Last change: Fri Sep 14 10:37:53 2012 via cibadmin on pcmk-2 +For example, if a 5-node cluster split into 3- and 2-node paritions, +the 3-node partition would have quorum and could continue serving resources. +If a 6-node cluster split into two 3-node partitions, neither partition +would have quorum; pacemaker's default behavior in such cases is to +stop all resources, in order to prevent data corruption. + +Two-node clusters are a special case. By the above definition, +a two-node cluster would only have quorum when both nodes are +running. This would make the creation of a two-node cluster pointless, +footnote:[Some would argue that two-node clusters are always pointless, but that is an argument for another time] +but corosync has the ability to treat two-node clusters as if only one node +is required for quorum. + +The `pcs cluster setup` command will automatically configure *two_node: 1* +in +corosync.conf+, so a two-node cluster will "just work". + +If you are using a different cluster shell, you will have to configure ++corosync.conf+ appropriately yourself. If you are using older versions of +corosync, you will have to ignore quorum at the pacemaker level, using `pcs +property set no-quorum-policy=ignore` (or the equivalent command if you are +using a different cluster shell). +==== + +Now, simulate node recovery by restarting the cluster stack on *pcmk-1*, and +check the cluster's status. + +---- +[root@pcmk-1 ~]# pcs cluster start pcmk-1 +pcmk-1: Starting Cluster... +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 10:50:11 2014 +Last change: Tue Dec 16 17:44:26 2014 Stack: corosync Current DC: pcmk-2 (2) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -1 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +1 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 ----- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# service corosync start -Starting Corosync Cluster Engine (corosync): [ OK ] -# service pacemaker start -Starting Pacemaker Cluster Manager: [ OK ] -# crm_mon -============ -Last updated: Fri Aug 28 15:32:13 2009 -Stack: openais -Current DC: pcmk-2 - partition with quorum -Version: 1.1.5-bdd89e69ba545404d02445be1f3d72e6a203ba2f -2 Nodes configured, 2 expected votes -1 Resources configured. -============ -Online: [ pcmk-1 pcmk-2 ] + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 + +PCSD Status: + pcmk-1: Online + pcmk-2: Online -ClusterIP (ocf::heartbeat:IPaddr): Started pcmk-2 +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -endif::[] [NOTE] ====== -In the dark days, the cluster may have moved the IP back to its -original location (+pcmk-1+). Usually this is no longer the case. +With older versions of pacemaker, the cluster might move the IP back to its +original location (*pcmk-1*). Usually, this is no longer the case. ====== -=== Prevent Resources from Moving after Recovery === +== Prevent Resources from Moving after Recovery == In most circumstances, it is highly desirable to prevent healthy resources from being moved around the cluster. Moving resources almost -always requires a period of downtime. For complex services like Oracle +always requires a period of downtime. For complex services such as databases, this period can be quite long. -To address this, Pacemaker has the concept of resource stickiness -which controls how much a service prefers to stay running where it +To address this, Pacemaker has the concept of resource _stickiness_, +which controls how strongly a service prefers to stay running where it is. You may like to think of it as the "cost" of any downtime. By default, Pacemaker assumes there is zero cost associated with moving resources and will do so to achieve "optimal" -footnote:[It should be noted that Pacemaker's definition of -optimal may not always agree with that of a human's. The order in which -Pacemaker processes lists of resources and nodes creates implicit -preferences in situations where the administrator has not explicitly -specified them] +footnote:[Pacemaker's definition of optimal may not always agree with that of a +human's. The order in which Pacemaker processes lists of resources and nodes +creates implicit preferences in situations where the administrator has not +explicitly specified them.] resource placement. We can specify a different stickiness for every resource, but it is often sufficient to change the default. -ifdef::pcs[] -[source,C] ---- -# pcs resource rsc defaults resource-stickiness=100 -# pcs resource rsc defaults +[root@pcmk-1 ~]# pcs resource defaults resource-stickiness=100 +[root@pcmk-1 ~]# pcs resource defaults resource-stickiness: 100 ---- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# crm configure rsc_defaults resource-stickiness=100 -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" ----- -endif::[] + +[NOTE] +====== +Earlier versions of pcs, such as the one shipped with Fedora 20, +require that `rsc` be added after `resource` in the above commands. +====== diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Apache.txt b/doc/Clusters_from_Scratch/en-US/Ch-Apache.txt index 236bb77e90..cbb1669bdc 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Apache.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Apache.txt @@ -1,795 +1,429 @@ -= Apache - Adding More Services = += Add Apache as a Cluster Service = -== Forward == Now that we have a basic but functional active/passive two-node cluster, we're ready to add some real services. We're going to start with Apache -because its a feature of many clusters and relatively simple to +because it is a feature of many clusters and relatively simple to configure. -== Installation == +== Install Apache == Before continuing, we need to make sure Apache is installed on both hosts. We also need the wget tool in order for the cluster to be able to check the status of the Apache server. -[source,C] +---- # yum install -y httpd wget +---- -..... -Loaded plugins: langpacks, presto, refresh-packagekit -fedora/metalink | 2.6 kB 00:00 -updates/metalink | 3.2 kB 00:00 -updates-testing/metalink | 41 kB 00:00 -Resolving Dependencies ---> Running transaction check ----> Package httpd.x86_64 0:2.2.22-3.fc17 will be installed ---> Processing Dependency: httpd-tools = 2.2.22-3.fc17 for package: httpd-2.2.22-3.fc17.x86_64 ---> Processing Dependency: apr-util-ldap for package: httpd-2.2.22-3.fc17.x86_64 ---> Processing Dependency: libaprutil-1.so.0()(64bit) for package: httpd-2.2.22-3.fc17.x86_64 ---> Processing Dependency: libapr-1.so.0()(64bit) for package: httpd-2.2.22-3.fc17.x86_64 ---> Running transaction check ----> Package apr.x86_64 0:1.4.6-1.fc17 will be installed ----> Package apr-util.x86_64 0:1.4.1-2.fc17 will be installed ----> Package apr-util-ldap.x86_64 0:1.4.1-2.fc17 will be installed ----> Package httpd-tools.x86_64 0:2.2.22-3.fc17 will be installed ---> Finished Dependency Resolution - -Dependencies Resolved - -===================================================================================== - Package Arch Version Repository Size -===================================================================================== -Installing: - httpd x86_64 2.2.22-3.fc17 updates-testing 823 k - wget x86_64 1.13.4-2.fc17 fedora 495 k -Installing for dependencies: - apr x86_64 1.4.6-1.fc17 fedora 99 k - apr-util x86_64 1.4.1-2.fc17 fedora 78 k - apr-util-ldap x86_64 1.4.1-2.fc17 fedora 17 k - httpd-tools x86_64 2.2.22-3.fc17 updates-testing 74 k - -Transaction Summary -===================================================================================== -Install 1 Package (+4 Dependent packages) - -Total download size: 1.1 M -Installed size: 3.5 M -Downloading Packages: -(1/6): apr-1.4.6-1.fc17.x86_64.rpm | 99 kB 00:00 -(2/6): apr-util-1.4.1-2.fc17.x86_64.rpm | 78 kB 00:00 -(3/6): apr-util-ldap-1.4.1-2.fc17.x86_64.rpm | 17 kB 00:00 -(4/6): httpd-2.2.22-3.fc17.x86_64.rpm | 823 kB 00:01 -(5/6): httpd-tools-2.2.22-3.fc17.x86_64.rpm | 74 kB 00:00 -(6/6): wget-1.13.4-2.fc17.x86_64.rpm | 495 kB 00:01 -------------------------------------------------------------------------------------- -Total 238 kB/s | 1.1 MB 00:04 -Running Transaction Check -Running Transaction Test -Transaction Test Succeeded -Running Transaction - Installing : apr-1.4.6-1.fc17.x86_64 1/6 - Installing : apr-util-1.4.1-2.fc17.x86_64 2/6 - Installing : apr-util-ldap-1.4.1-2.fc17.x86_64 3/6 - Installing : httpd-tools-2.2.22-3.fc17.x86_64 4/6 - Installing : httpd-2.2.22-3.fc17.x86_64 5/6 - Installing : wget-1.13.4-2.fc17.x86_64 6/6 - Verifying : apr-util-ldap-1.4.1-2.fc17.x86_64 1/6 - Verifying : httpd-tools-2.2.22-3.fc17.x86_64 2/6 - Verifying : apr-util-1.4.1-2.fc17.x86_64 3/6 - Verifying : apr-1.4.6-1.fc17.x86_64 4/6 - Verifying : httpd-2.2.22-3.fc17.x86_64 5/6 - Verifying : wget-1.13.4-2.fc17.x86_64 6/6 - -Installed: - httpd.x86_64 0:2.2.22-3.fc17 wget.x86_64 0:1.13.4-2.fc17 - -Dependency Installed: - apr.x86_64 0:1.4.6-1.fc17 apr-util.x86_64 0:1.4.1-2.fc17 - apr-util-ldap.x86_64 0:1.4.1-2.fc17 httpd-tools.x86_64 0:2.2.22-3.fc17 - -Complete! -..... - -== Preparation == - -First we need to create a page for Apache to serve up. On Fedora the -default Apache docroot is /var/www/html, so we'll create an index file -there. - -[source,C] ------ -# cat <<-END >/var/www/html/index.html - - My Test Site - pcmk-1 - -END ------ +[IMPORTANT] +==== +Do *not* enable the httpd service. Services that are intended to +be managed via the cluster software should never be managed by the OS. + +It is often useful, however, to manually start the service, verify that +it works, then stop it again, before adding it to the cluster. This +allows you to resolve any non-cluster-related problems before continuing. +Since this is a simple example, we'll skip that step here. +==== -For the moment, we will simplify things by serving up only a static site -and manually sync the data between the two nodes. So run the command -again on pcmk-2. +== Create Website Documents == + +We need to create a page for Apache to serve. On Fedora, the +default Apache document root is /var/www/html, so we'll create an index file +there. For the moment, we will simplify things by serving a static site +and manually synchronizing the data between the two nodes, so run this command +on both nodes: -[source,C] ----- -[root@pcmk-2 ~]# cat <<-END >/var/www/html/index.html +# cat <<-END >/var/www/html/index.html - My Test Site - pcmk-2 + My Test Site - $(hostname) - END +END ----- == Enable the Apache status URL == In order to monitor the health of your Apache instance, and recover it if it fails, the resource agent used by Pacemaker assumes the server-status -URL is available. Look for the following in '/etc/httpd/conf/httpd.conf' -and make sure it is not disabled or commented out: +URL is available. On both nodes, enable the URL with: -[source,C] ------ - - SetHandler server-status - Order deny,allow - Deny from all - Allow from 127.0.0.1 - ------ +---- +# cat <<-END >/etc/httpd/conf.d/status.conf + + SetHandler server-status + Order deny,allow + Deny from all + Allow from 127.0.0.1 + +END +---- + +[NOTE] +====== +If you are using a different operating system or an earlier version of Fedora, +server-status may already be enabled or may be configurable in a different +location. +====== -== Update the Configuration == +== Configure the Cluster == -At this point, Apache is ready to go, all that needs to be done is to -add it to the cluster. Lets call the resource WebSite. We need to use -an OCF script called apache in the heartbeat namespace -footnote:[Compare the key used here ocf:heartbeat:apache with the one we used earlier for the IP address: ocf:heartbeat:IPaddr2] -, the only required parameter is the path to the main Apache -configuration file and we'll tell the cluster to check once a -minute that apache is still running. +At this point, Apache is ready to go, and all that needs to be done is to +add it to the cluster. Let's call the resource WebSite. We need to use +an OCF resource script called apache in the heartbeat namespace. +footnote:[Compare the key used here, *ocf:heartbeat:apache*, with the one we +used earlier for the IP address, *ocf:heartbeat:IPaddr2*] +The script's only required parameter is the path to the main Apache +configuration file, and we'll tell the cluster to check once a +minute that Apache is still running. -ifdef::pcs[] -//// -source,C doesn't deal well with \'s -//// ------ -pcs resource create WebSite ocf:heartbeat:apache \ +---- +[root@pcmk-1 ~]# pcs resource create WebSite ocf:heartbeat:apache \ configfile=/etc/httpd/conf/httpd.conf \ - statusurl="http://localhost/server-status" op monitor interval=1min ------ + statusurl="http://localhost/server-status" \ + op monitor interval=1min +---- -By default, the operation timeout for all resource's start, stop, and monitor -operations is 20 seconds. In many cases this timeout period is less than -the advised timeout period. For the purposes of this tutorial, we will -adjust the global operation timeout default to 240 seconds. +By default, the operation timeout for all resources' start, stop, and monitor +operations is 20 seconds. In many cases, this timeout period is less than +a particular resource's advised timeout period. For the purposes of this +tutorial, we will adjust the global operation timeout default to 240 seconds. -[source,C] ------ -# pcs resource op defaults timeout=240s -# pcs resource op defaults +---- +[root@pcmk-1 ~]# pcs resource op defaults timeout=240s +[root@pcmk-1 ~]# pcs resource op defaults timeout: 240s ------ - -endif::[] - -ifdef::crmsh[] -[source,Bash] ------ -# crm configure primitive WebSite ocf:heartbeat:apache \ - params configfile=/etc/httpd/conf/httpd.conf \ - statusurl="http://localhost/server-status" \ - op monitor interval=1min -WARNING: WebSite: default timeout 20s for start is smaller than the advised 40s -WARNING: WebSite: default timeout 20s for stop is smaller than the advised 60s ------ - -The easiest way resolve this, is to change the default: +---- -[source,Bash] ------ -# crm configure op_defaults timeout=240s -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" ------ -endif::[] +[NOTE] +====== +In a production cluster, it is usually better to adjust each resource's +start, stop, and monitor timeouts to values that are appropriate to +the behavior observed in your environment, rather than adjust +the global default. +====== -After a short delay, we should see the cluster start apache +After a short delay, we should see the cluster start Apache. -ifdef::pcs[] -[source,C] ----- -# pcs status - -Last updated: Fri Sep 14 10:51:27 2012 -Last change: Fri Sep 14 10:50:46 2012 via crm_attribute on pcmk-1 +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 12:40:41 2014 +Last change: Wed Dec 17 12:40:05 2014 Stack: corosync Current DC: pcmk-2 (2) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -2 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +2 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf::heartbeat:apache): Started pcmk-1 ------ -endif::[] - -ifdef::crmsh[] -[source,C] ------ -# crm_mon -1 -============ -Last updated: Tue Apr 3 11:54:29 2012 -Last change: Tue Apr 3 11:54:26 2012 via crmd on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -2 Resources configured. -============ + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 + WebSite (ocf::heartbeat:apache): Started pcmk-1 -Online: [ pcmk-1 pcmk-2 ] +PCSD Status: + pcmk-1: Online + pcmk-2: Online -ClusterIP (ocf:heartbeat:IPaddr2): Started pcmk-2 -WebSite (ocf:heartbeat:apache): Started pcmk-1 +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ----- -endif::[] Wait a moment, the WebSite resource isn't running on the same host as our IP address! -ifdef::pcs[] [NOTE] ====== If, in the `pcs status` output, you see the WebSite resource has failed to start, then you've likely not enabled the status URL correctly. -You can check if this is the problem by running: - -.... -wget http://127.0.0.1/server-status -.... - -If you see +Connection refused+ in the output, then this is indeed the -problem. Check to ensure that +Allow from 127.0.0.1+ is present for -the ++ block. - -====== -endif::[] - -ifdef::crmsh[] -[NOTE] -====== -If, in the `crm_mon` output, you see: - -.... -Failed actions: - WebSite_start_0 (node=pcmk-2, call=301, rc=1, status=complete): unknown error -.... - -Then you've likely not enabled the status URL correctly. -You can check if this is the problem by running: +You can check whether this is the problem by running: .... -wget http://127.0.0.1/server-status +wget -O - http://127.0.0.1/server-status .... -If you see +Connection refused+ in the output, then this is indeed the -problem. Check to ensure that +Allow from 127.0.0.1+ is present for -the ++ block. +If you see *Connection refused* in the output, then this is likely the +problem. Ensure that *Allow from 127.0.0.1* is present for +the ** block. ====== -endif::[] -== Ensuring Resources Run on the Same Host == +== Ensure Resources Run on the Same Host == To reduce the load on any one machine, Pacemaker will generally try to -spread the configured resources across the cluster nodes. However we +spread the configured resources across the cluster nodes. However, we can tell the cluster that two resources are related and need to run on -the same host (or not at all). Here we instruct the cluster that +the same host (or not at all). Here, we instruct the cluster that WebSite can only run on the host that ClusterIP is active on. -ifdef::pcs[] -To achieve this we use a colocation constraint that indicates it is +To achieve this, we use a _colocation constraint_ that indicates it is mandatory for WebSite to run on the same node as ClusterIP. The "mandatory" part of the colocation constraint is indicated by using a score of INFINITY. The INFINITY score also means that if ClusterIP is not active anywhere, WebSite will not be permitted to run. -endif::[] - -ifdef::crmsh[] -For the constraint, we need a name (choose something descriptive like -website-with-ip), indicate that its mandatory (so that if ClusterIP is -not active anywhere, WebSite will not be permitted to run anywhere -either) by specifying a score of INFINITY and finally list the two -resources. -endif::[] [NOTE] ======= If ClusterIP is not active anywhere, WebSite will not be permitted to run anywhere. ======= [IMPORTANT] =========== - Colocation constraints are "directional", in that they imply certain things about the order in which the two resources will have a location -chosen. In this case we're saying +WebSite+ needs to be placed on the -same machine as +ClusterIP+, this implies that we must know the -location of +ClusterIP+ before choosing a location for +WebSite+. - +chosen. In this case, we're saying that *WebSite* needs to be placed on the +same machine as *ClusterIP*, which implies that the cluster must know the +location of *ClusterIP* before choosing a location for *WebSite*. =========== -ifdef::pcs[] -[source,C] ----- -# pcs constraint colocation add WebSite ClusterIP INFINITY -# pcs constraint +[root@pcmk-1 ~]# pcs constraint colocation add WebSite with ClusterIP INFINITY +[root@pcmk-1 ~]# pcs constraint Location Constraints: Ordering Constraints: Colocation Constraints: - WebSite with ClusterIP -# pcs status - -Last updated: Fri Sep 14 11:00:44 2012 -Last change: Fri Sep 14 11:00:25 2012 via cibadmin on pcmk-1 + WebSite with ClusterIP (score:INFINITY) +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 13:57:58 2014 +Last change: Wed Dec 17 13:57:22 2014 Stack: corosync Current DC: pcmk-2 (2) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -2 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +2 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf::heartbeat:apache): Started pcmk-2 ------ -endif::[] + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 + WebSite (ocf::heartbeat:apache): Started pcmk-2 -ifdef::crmsh[] -[source,C] ------ -# crm configure colocation website-with-ip INFINITY: WebSite ClusterIP -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -colocation website-with-ip inf: WebSite ClusterIP -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" \ - last-lrm-refresh="1333446866" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" -# crm_mon -1 -============ -Last updated: Tue Apr 3 11:57:13 2012 -Last change: Tue Apr 3 11:56:10 2012 via cibadmin on pcmk-1 -Stack: corosync -Current DC: pcmk-2 (1719314624) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -2 Resources configured. -============ - -Online: [ pcmk-1 pcmk-2 ] +PCSD Status: + pcmk-1: Online + pcmk-2: Online - ClusterIP (ocf:heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf:heartbeat:apache): Started pcmk-2 +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ----- -endif::[] -== Controlling Resource Start/Stop Ordering == +== Ensure Resources Start and Stop in Order == + +Like many services, Apache can be configured to bind to specific +IP addresses on a host or to the wildcard IP address. If Apache +binds to the wildcard, it doesn't matter whether an IP address +is added before or after Apache starts; Apache will respond on +that IP just the same. However, if Apache binds only to certain IP +address(es), the order matters: If the address is added after Apache +starts, Apache won't respond on that address. -When Apache starts, it binds to the available IP addresses. It doesn't -know about any addresses we add afterwards, so not only do they need to -run on the same node, but we need to make sure ClusterIP is already -active before we start WebSite. We do this by adding an ordering -constraint. +To be sure our WebSite responds regardless of Apache's address configuration, +we need to make sure ClusterIP not only runs on the same node, +but starts before WebSite. A colocation constraint only ensures the +resources run together, not the order in which they are started and stopped. -ifdef::pcs[] -By default all order constraints are mandatory constraints unless -otherwise configured. This means that the recovery of ClusterIP will -also trigger the recovery of WebSite. +We do this by adding an ordering constraint. By default, all order constraints +are mandatory, which means that the recovery of ClusterIP will also trigger the +recovery of WebSite. -[source,C] ----- -# pcs constraint order ClusterIP then WebSite +[root@pcmk-1 ~]# pcs constraint order ClusterIP then WebSite Adding ClusterIP WebSite (kind: Mandatory) (Options: first-action=start then-action=start) -# pcs constraint +[root@pcmk-1 ~]# pcs constraint Location Constraints: Ordering Constraints: - start ClusterIP then start WebSite + start ClusterIP then start WebSite (kind:Mandatory) Colocation Constraints: - WebSite with ClusterIP ------ -endif::[] - -ifdef::crmsh[] - -We need to give it a name (choose something descriptive like -apache-after-ip), indicate that its mandatory (so that any recovery for -ClusterIP will also trigger recovery of WebSite) and list the two -resources in the order we need them to start. - -[source,C] ------ -# crm configure order apache-after-ip mandatory: ClusterIP WebSite -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -colocation website-with-ip inf: WebSite ClusterIP -order apache-after-ip inf: ClusterIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" \ - last-lrm-refresh="1333446866" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" + WebSite with ClusterIP (score:INFINITY) ----- -endif::[] -== Specifying a Preferred Location == +== Prefer One Node Over Another == Pacemaker does not rely on any sort of hardware symmetry between nodes, so it may well be that one machine is more powerful than the other. In -such cases it makes sense to host the resources there if it is available. -To do this we create a location constraint. +such cases, it makes sense to host the resources on the more powerful node if +it is available. To do this, we create a location constraint. -ifdef::pcs[] In the location constraint below, we are saying the WebSite resource -prefers the node pcmk-1 with a score of 50. The score here indicates -how badly we'd like the resource to run somewhere. +prefers the node pcmk-1 with a score of 50. Here, the score indicates +how badly we'd like the resource to run at this location. -[source,C] ----- -# pcs constraint location WebSite prefers pcmk-1=50 -# pcs constraint +[root@pcmk-1 ~]# pcs constraint location WebSite prefers pcmk-1=50 +[root@pcmk-1 ~]# pcs constraint Location Constraints: Resource: WebSite Enabled on: pcmk-1 (score:50) Ordering Constraints: - start ClusterIP then start WebSite + start ClusterIP then start WebSite (kind:Mandatory) Colocation Constraints: - WebSite with ClusterIP -# pcs status -Last updated: Fri Sep 14 11:06:37 2012 -Last change: Fri Sep 14 11:06:26 2012 via cibadmin on pcmk-1 + WebSite with ClusterIP (score:INFINITY) +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 14:11:49 2014 +Last change: Wed Dec 17 14:11:20 2014 Stack: corosync Current DC: pcmk-2 (2) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -2 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +2 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf::heartbeat:apache): Started pcmk-2 ------ -endif::[] + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 + WebSite (ocf::heartbeat:apache): Started pcmk-2 -ifdef::crmsh[] -Again we give it a descriptive name (prefer-pcmk-1), specify the resource we -want to run there (WebSite), how badly we'd like it to run there (we'll use -50 for now, but in a two-node situation almost any value above 0 will do) and -the host's name. +PCSD Status: + pcmk-1: Online + pcmk-2: Online -[source,C] ------ -# crm configure location prefer-pcmk-1 WebSite 50: pcmk-1 -WARNING: prefer-pcmk-1: referenced node pcmk-1 does not exist +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ----- -This warning should be ignored. - -[source,C] ------ -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -location prefer-pcmk-1 WebSite 50: pcmk-1 -colocation website-with-ip inf: WebSite ClusterIP -order apache-after-ip inf: ClusterIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" \ - last-lrm-refresh="1333446866" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" -# crm_mon -1 -============ -Last updated: Tue Apr 3 12:02:14 2012 -Last change: Tue Apr 3 11:59:42 2012 via cibadmin on pcmk-1 -Stack: corosync -Current DC: pcmk-2 (1719314624) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -2 Resources configured. -============ - -Online: [ pcmk-1 pcmk-2 ] - - ClusterIP (ocf:heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf:heartbeat:apache): Started pcmk-2 ------ -endif::[] - Wait a minute, the resources are still on pcmk-2! -Even though we now prefer pcmk-1 over pcmk-2, that preference is +Even though WebSite now prefers to run on pcmk-1, that preference is (intentionally) less than the resource stickiness (how much we preferred not to have unnecessary downtime). -To see the current placement scores, you can use a tool called crm_simulate +To see the current placement scores, you can use a tool called crm_simulate. -[source,C] ---- -# crm_simulate -sL +[root@pcmk-1 ~]# crm_simulate -sL + Current cluster status: Online: [ pcmk-1 pcmk-2 ] - ClusterIP (ocf:heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf:heartbeat:apache): Started pcmk-2 + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 + WebSite (ocf::heartbeat:apache): Started pcmk-2 Allocation scores: native_color: ClusterIP allocation score on pcmk-1: 50 native_color: ClusterIP allocation score on pcmk-2: 200 native_color: WebSite allocation score on pcmk-1: -INFINITY native_color: WebSite allocation score on pcmk-2: 100 Transition Summary: ---- -== Manually Moving Resources Around the Cluster == +== Move Resources Manually == -ifdef::pcs[] There are always times when an administrator needs to override the -cluster and force resources to move to a specific location. By -updating our previous location constraint with a score of INFINITY, -WebSite will be forced to move to pcmk-1. +cluster and force resources to move to a specific location. In this example, +we will force the WebSite to move to pcmk-1 by +updating our previous location constraint with a score of INFINITY. -[source,C] ----- -# pcs constraint location WebSite prefers pcmk-1=INFINITY -# pcs constraint all +[root@pcmk-1 ~]# pcs constraint location WebSite prefers pcmk-1=INFINITY +[root@pcmk-1 ~]# pcs constraint Location Constraints: Resource: WebSite - Enabled on: pcmk-1 (score:INFINITY) (id:location-WebSite-pcmk-1-INFINITY) + Enabled on: pcmk-1 (score:INFINITY) Ordering Constraints: - start ClusterIP then start WebSite (Mandatory) (id:order-ClusterIP-WebSite-mandatory) + start ClusterIP then start WebSite (kind:Mandatory) Colocation Constraints: - WebSite with ClusterIP (INFINITY) (id:colocation-WebSite-ClusterIP-INFINITY) -# pcs status - -Last updated: Fri Sep 14 11:16:26 2012 -Last change: Fri Sep 14 11:16:18 2012 via cibadmin on pcmk-1 + WebSite with ClusterIP (score:INFINITY) +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 14:19:34 2014 +Last change: Wed Dec 17 14:18:37 2014 Stack: corosync Current DC: pcmk-2 (2) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -2 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +2 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 - WebSite (ocf::heartbeat:apache): Started pcmk-1 ------ -endif::[] + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 + WebSite (ocf::heartbeat:apache): Started pcmk-1 -ifdef::crmsh[] -There are always times when an administrator needs to override the -cluster and force resources to move to a specific location. Underneath we -use location constraints like the one we created above, happily you don't -need to care. Just provide the name of the resource and the intended -location, we'll do the rest. +PCSD Status: + pcmk-1: Online + pcmk-2: Online -[source,C] ------ -# crm resource move WebSite pcmk-1 -# crm_mon -1 -============ -Last updated: Tue Apr 3 12:03:41 2012 -Last change: Tue Apr 3 12:03:37 2012 via crm_resource on pcmk-1 -Stack: corosync -Current DC: pcmk-2 (1719314624) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -2 Resources configured. -============ - -Online: [ pcmk-1 pcmk-2 ] - - ClusterIP (ocf:heartbeat:IPaddr2): Started pcmk-1 - WebSite (ocf:heartbeat:apache): Started pcmk-1 ------ - -Notice how the colocation rule we created has ensured that ClusterIP was also moved to pcmk-1. -For the curious, we can see the effect of this command by examining the configuration - -[source,C] ------ -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -location cli-prefer-WebSite WebSite \ - rule $id="cli-prefer-rule-WebSite" inf: #uname eq pcmk-1 -location prefer-pcmk-1 WebSite 50: pcmk-1 -colocation website-with-ip inf: WebSite ClusterIP -order apache-after-ip inf: ClusterIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" \ - last-lrm-refresh="1333446866" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ----- -The automated constraint used to move the resources to +pcmk-1+ is the -line beginning with +location cli-prefer-WebSite+. -endif::[] - -=== Giving Control Back to the Cluster === - -Once we've finished whatever activity that required us to move the -resources to pcmk-1, in our case nothing, we can then allow the cluster -to resume normal operation with the unmove command. Since we previously +Once we've finished whatever activity required us to move the +resources to pcmk-1 (in our case nothing), we can then allow the cluster +to resume normal operation by removing the new constraint. Since we previously configured a default stickiness, the resources will remain on pcmk-1. -ifdef::pcs[] -[source,C] +First, use the `--full` option to get the constraint's ID: ----- -# pcs constraint all +[root@pcmk-1 ~]# pcs constraint --full Location Constraints: Resource: WebSite Enabled on: pcmk-1 (score:INFINITY) (id:location-WebSite-pcmk-1-INFINITY) Ordering Constraints: - start ClusterIP then start WebSite (Mandatory) (id:order-ClusterIP-WebSite-mandatory) -Colocation Constraints: - WebSite with ClusterIP (INFINITY) (id:colocation-WebSite-ClusterIP-INFINITY) -# pcs constraint rm location-WebSite-pcmk-1-INFINITY -# pcs constraint -Location Constraints: -Ordering Constraints: - start ClusterIP then start WebSite + start ClusterIP then start WebSite (kind:Mandatory) (id:order-ClusterIP-WebSite-mandatory) Colocation Constraints: - WebSite with ClusterIP + WebSite with ClusterIP (score:INFINITY) (id:colocation-WebSite-ClusterIP-INFINITY) ----- -endif::[] -ifdef::crmsh[] -[source,C] +Then remove the desired contraint using its ID: ----- -# crm resource unmove WebSite -# crm configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -location prefer-pcmk-1 WebSite 50: pcmk-1 -colocation website-with-ip inf: WebSite ClusterIP -order apache-after-ip inf: ClusterIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" \ - last-lrm-refresh="1333446866" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" +[root@pcmk-1 ~]# pcs constraint remove location-WebSite-pcmk-1-INFINITY +[root@pcmk-1 ~]# pcs constraint +Location Constraints: +Ordering Constraints: + start ClusterIP then start WebSite (kind:Mandatory) +Colocation Constraints: + WebSite with ClusterIP (score:INFINITY) ----- -endif::[] -Note that the constraint is now gone. If we check the cluster -status, we can also see that as expected the resources are still active +Note that the location constraint is now gone. If we check the cluster +status, we can also see that (as expected) the resources are still active on pcmk-1. -ifdef::pcs[] -[source,C] ----- # pcs status - -Last updated: Fri Sep 14 11:57:12 2012 -Last change: Fri Sep 14 11:57:03 2012 via cibadmin on pcmk-1 +Cluster name: mycluster +Last updated: Wed Dec 17 14:25:21 2014 +Last change: Wed Dec 17 14:24:29 2014 Stack: corosync Current DC: pcmk-2 (2) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -2 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +2 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 - WebSite (ocf::heartbeat:apache): Started pcmk-1 ------ -endif::[] + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 + WebSite (ocf::heartbeat:apache): Started pcmk-1 -ifdef::crmsh[] -[source,C] ------ -# crm_mon -============ -Last updated: Tue Apr 3 12:05:08 2012 -Last change: Tue Apr 3 12:03:37 2012 via crm_resource on pcmk-1 -Stack: corosync -Current DC: pcmk-2 (1719314624) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -2 Resources configured. -============ - -Online: [ pcmk-1 pcmk-2 ] +PCSD Status: + pcmk-1: Online + pcmk-2: Online - ClusterIP (ocf:heartbeat:IPaddr2): Started pcmk-1 - WebSite (ocf:heartbeat:apache): Started pcmk-1 +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ----- -endif::[] diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Installation.txt b/doc/Clusters_from_Scratch/en-US/Ch-Installation.txt index aa0b4b96f7..0cdc71d956 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Installation.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Installation.txt @@ -1,651 +1,527 @@ = Installation = -== OS Installation == +== Install the OS == Detailed instructions for installing Fedora are available at -http://docs.fedoraproject.org/en-US/Fedora/20/html/Installation_Guide/ in a number of -languages. The abbreviated version is as follows... +http://docs.fedoraproject.org/en-US/Fedora/21/html/Installation_Guide/ in a number of +languages. The abbreviated version is as follows: -Point your browser to http://fedoraproject.org/en/get-fedora-all, -locate the +Install Media+ section and download the install DVD that -matches your hardware. +Point your browser to https://getfedora.org/, +choose a flavor (Server is an appropriate choice), +and download the installation image appropriate to your hardware. -Burn the disk image to a DVD -footnote:[http://docs.fedoraproject.org/en-US/Fedora/20/html/Burning_ISO_images_to_disc/index.html] +Burn the installation image to a DVD or USB drive +footnote:[http://docs.fedoraproject.org/en-US/Fedora/21/html/Installation_Guide/sect-preparing-boot-media.html] and boot from it, or use the image to boot a virtual machine. -After clicking through the welcome screen, select your language, -keyboard layout -footnote:[http://docs.fedoraproject.org/en-US/Fedora/20/html/Installation_Guide/language-selection-x86.html] +After starting the installation, select your language and keyboard layout at +the welcome screen. +footnote:[http://docs.fedoraproject.org/en-US/Fedora/21/html/Installation_Guide/sect-installation-graphical-mode.html] -At this point you get a chance to tweak the default installation options. +At this point, you get a chance to tweak the default installation options. -In the +Network Configuration+ section you'll want to: +In the *NETWORK & HOSTNAME* section you'll want to: -- Assign your machine a host name +- Assign your machine a host name. I happen to control the clusterlabs.org domain name, so I will use - that here. -- Assign a fixed IP address + pcmk-1.clusterlabs.org here. +- Assign a fixed IPv4 address. In this example, I'll use 192.168.122.101. [IMPORTANT] =========== Do not accept the default network settings. -Cluster machines should never obtain an IP address via DHCP. +Cluster machines should never obtain an IP address via DHCP, because +DHCP's periodic address renewal will interfere with corosync. -If you miss this step, this can easily be configured after installation. You will have -to navigate to +system settings+ and select +network+. From there you can select +If you miss this step during installation, it can easily be fixed later. You will have +to navigate to *system settings* and select *network*. From there, you can select what device to configure. =========== -In the +Software Selection+ section (try saying that 10 times -quickly), choose +Minimal Install+ so that we see everything that gets -installed. Don't enable updates yet, we'll do that (and install any -extra software we need) later. +In the *Software Selection* section (try saying that 10 times +quickly), leave all *Add-Ons* unchecked so that we see everything that gets +installed. We'll install any extra software we need later. [IMPORTANT] =========== By default Fedora uses LVM for partitioning which allows us to dynamically change the amount of space allocated to a given partition. However, by default it also allocates all free space to the +/+ -(aka. +root+) partition which cannot be dynamically _reduced_ in size -(dynamic increases are fine by-the-way). +(aka. *root*) partition, which cannot be dynamically _reduced_ in size +(dynamic increases are fine, by the way). So if you plan on following the DRBD or GFS2 portions of this guide, -you should reserve at least 1Gb of space on each machine from which to -create a shared volume. To do so, enter the +Installation -Destination+ section where you are be given an opportunity to reduce -the size of the +root+ partition (after chosing which hard drive you -wish to install to). +you should reserve at least 1GiB of space on each machine from which to +create a shared volume. To do so, enter the *Installation +Destination* section where you are be given an opportunity to reduce +the size of the *root* partition (after choosing which hard drive you +wish to install to). If you want the reserved space to be available +within an LVM volume group, be sure to select *Modify...* next to +the volume group name and change the *Size policy:* to *Fixed* +or *As large as possible*. =========== It is highly recommended to enable NTP on your cluster nodes. Doing so ensures all nodes agree on the current time and makes reading log files -significantly easier. You can do this in the +Date & Time+ section. -footnote:[http://docs.fedoraproject.org/en-US/Fedora/20/html/Installation_Guide/s1-timezone-x86.html] +significantly easier. You can do this in the *DATE & TIME* section. +footnote:[http://docs.fedoraproject.org/en-US/Fedora/21/html/Installation_Guide/sect-installation-gui-date-and-time.html] - - -Once the node reboots, you'll see a (possibly mangled) login prompt on -the console. Login using +root+ and the password you created earlier. +Once you've completed the installation, set a root password as instructed. +For the purposes of this document, it is not necessary to create any additional +users. After the node reboots, you'll see a (possibly mangled) login prompt on +the console. Login using *root* and the password you created earlier. image::images/Console.png["Initial Console",align="center",scaledwidth="65%"] [NOTE] ====== -From here on in we're going to be working exclusively from the terminal. +From here on, we're going to be working exclusively from the terminal. ====== -== Post Installation Tasks == +== Configure the OS == -=== Networking === +=== Verify Networking === -Check the machine has the static IP address you configured earlier +Ensure that the machine has the static IP address you configured earlier. -[source,C] ----- -# ip addr -1: lo: mtu 16436 qdisc noqueue state UNKNOWN +[root@pcmk-1 ~]# ip addr +1: lo: mtu 65536 qdisc noqueue state UNKNOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo inet6 ::1/128 scope host valid_lft forever preferred_lft forever -2: eth0: mtu 1500 qdisc pfifo_fast state UP qlen 1000 +2: eth0: mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 52:54:00:d7:d6:08 brd ff:ff:ff:ff:ff:ff inet 192.168.122.101/24 brd 192.168.122.255 scope global eth0 + valid_lft forever preferred_lft forever inet6 fe80::5054:ff:fed7:d608/64 scope link valid_lft forever preferred_lft forever ----- [NOTE] ===== -If you ever need to change the node's IP address from the command line follow these instructions: +If you ever need to change the node's IP address from the command line, follow these instructions: .... -# manually edit /etc/sysconfig/network-scripts/ifcfg-${device} -# nmcli dev disconnect ${device} -# nmcli con reload ${device} -# nmcli con up ${device} +[root@pcmk-1 ~]# vim /etc/sysconfig/network-scripts/ifcfg-${device} # manually edit as desired +[root@pcmk-1 ~]# nmcli dev disconnect ${device} +[root@pcmk-1 ~]# nmcli con reload ${device} +[root@pcmk-1 ~]# nmcli con up ${device} .... -This makes +NetworkManager+ aware that a change was made on the config file. +This makes *NetworkManager* aware that a change was made on the config file. ===== -Next, check the routes are ok: +Next, ensure that the routes are as expected: -[source,C] ----- [root@pcmk-1 ~]# ip route -default via 192.168.122.1 dev eth0 +default via 192.168.122.1 dev eth0 proto static metric 1024 192.168.122.0/24 dev eth0 proto kernel scope link src 192.168.122.101 ----- -If there is no line beginning with +default via+, then you may need to add a line such as +If there is no line beginning with *default via*, then you may need to add a line such as [source,Bash] GATEWAY=192.168.122.1 -to '/etc/sysconfig/network' and restart the network. +to +/etc/sysconfig/network+ and restart the network. -Now check for connectivity to the outside world. Start small by -testing if we can read the gateway we configured. +Now, check for connectivity to the outside world. Start small by +testing whether we can reach the gateway we configured. -[source,C] ----- -# ping -c 1 192.168.122.1 +[root@pcmk-1 ~]# ping -c 1 192.168.122.1 PING 192.168.122.1 (192.168.122.1) 56(84) bytes of data. 64 bytes from 192.168.122.1: icmp_req=1 ttl=64 time=0.249 ms --- 192.168.122.1 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 0.249/0.249/0.249/0.000 ms ----- -Now try something external, choose a location you know will be available. +Now try something external; choose a location you know should be available. -[source,C] ----- -# ping -c 1 www.google.com +[root@pcmk-1 ~]# ping -c 1 www.google.com PING www.l.google.com (173.194.72.106) 56(84) bytes of data. 64 bytes from tf-in-f106.1e100.net (173.194.72.106): icmp_req=1 ttl=41 time=167 ms --- www.l.google.com ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 167.618/167.618/167.618/0.000 ms ----- -=== Leaving the Console === +=== Login Remotely === -The console isn't a very friendly place to work from, we will now +The console isn't a very friendly place to work from, so we will now switch to accessing the machine remotely via SSH where we can -use copy&paste etc. +use copy and paste, etc. -First we check we can see the newly installed at all: +From another host, check whether we can see the new host at all: -[source,C] ----- beekhof@f16 ~ # ping -c 1 192.168.122.101 PING 192.168.122.101 (192.168.122.101) 56(84) bytes of data. 64 bytes from 192.168.122.101: icmp_req=1 ttl=64 time=1.01 ms --- 192.168.122.101 ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev = 1.012/1.012/1.012/0.000 ms ----- -Next we login via SSH +Next, login as root via SSH. -[source,C] ----- beekhof@f16 ~ # ssh -l root 192.168.122.11 root@192.168.122.11's password: Last login: Fri Mar 30 19:41:19 2012 from 192.168.122.1 [root@pcmk-1 ~]# ----- -=== Security Shortcuts === +=== Apply Updates === + +Apply any package updates released since your installation image was created: +---- +[root@pcmk-1 ~]# yum update +---- + +=== Disable Security During Testing === To simplify this guide and focus on the aspects directly connected to clustering, we will now disable the machine's firewall and SELinux installation. [WARNING] =========== -Both of these actions create significant security issues -and should not be performed on machines that will be exposed to the -outside world. +These actions create significant security issues and should not be performed on +machines that will be exposed to the outside world. =========== -[IMPORTANT] -=========== +//// TODO: Create an Appendix that deals with (at least) re-enabling the firewall. -=========== +//// -[source,C] ---- -# setenforce 0 -# sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config -# systemctl disable firewalld.service -# systemctl stop firewalld.service +[root@pcmk-1 ~]# setenforce 0 +[root@pcmk-1 ~]# sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config +[root@pcmk-1 ~]# systemctl disable firewalld.service +[root@pcmk-1 ~]# systemctl stop firewalld.service +[root@pcmk-1 ~]# iptables --flush ---- -or (on older Fedora) +[NOTE] +=========== +If you are using Fedora 17 or earlier or are using the iptables +service for your firewall, the commands would be: -[source,C] ---- -# setenforce 0 -# sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config -# systemctl disable iptables.service -# rm '/etc/systemd/system/basic.target.wants/iptables.service' -# systemctl stop iptables.service +[root@pcmk-1 ~]# setenforce 0 +[root@pcmk-1 ~]# sed -i.bak "s/SELINUX=enforcing/SELINUX=permissive/g" /etc/selinux/config +[root@pcmk-1 ~]# systemctl disable iptables.service +[root@pcmk-1 ~]# rm -f /etc/systemd/system/basic.target.wants/iptables.service +[root@pcmk-1 ~]# systemctl stop iptables.service +[root@pcmk-1 ~]# iptables --flush ---- +=========== - -=== Short Node Names === +=== Use Short Node Names === During installation, we filled in the machine's fully qualified domain -name (FQDN) which can be rather long when it appears in cluster logs and +name (FQDN), which can be rather long when it appears in cluster logs and status output. See for yourself how the machine identifies itself: (((Nodes, short name))) -[source,C] ---- -# uname -n +[root@pcmk-1 ~]# uname -n pcmk-1.clusterlabs.org -# dnsdomainname +[root@pcmk-1 ~]# dnsdomainname clusterlabs.org ---- (((Nodes, Domain name (Query)))) The output from the second command is fine, but we really don't need the domain name included in the basic host details. To address this, we need -to use the +hostnamectl+ tool to strip off the domain name. -[source,C] +to use the `hostnamectl` tool to strip off the domain name. ---- -# hostnamectl set-hostname $(uname -n | sed s/\\..*//)' +[root@pcmk-1 ~]# hostnamectl set-hostname $(uname -n | sed s/\\..*//) ---- (((Nodes, Domain name (Remove from host name)))) Now check the machine is using the correct names -[source,C] ---- -# uname -n +[root@pcmk-1 ~]# uname -n pcmk-1 -# dnsdomainname +[root@pcmk-1 ~]# dnsdomainname clusterlabs.org ---- If it concerns you that the shell prompt has not been updated, simply log out and back in again. -== Before You Continue == +== Repeat for Second Node == Repeat the Installation steps so far, so that you have two Fedora nodes ready to have the cluster software installed. For the purposes of this document, the additional node is called pcmk-2 with address 192.168.122.102. -=== Finalize Networking === +== Configure Communication Between Nodes == + +=== Configure Host Name Resolution === Confirm that you can communicate between the two new nodes: -[source,C] ---- -# ping -c 3 192.168.122.102 +[root@pcmk-1 ~]# ping -c 3 192.168.122.102 PING 192.168.122.102 (192.168.122.102) 56(84) bytes of data. 64 bytes from 192.168.122.102: icmp_seq=1 ttl=64 time=0.343 ms 64 bytes from 192.168.122.102: icmp_seq=2 ttl=64 time=0.402 ms 64 bytes from 192.168.122.102: icmp_seq=3 ttl=64 time=0.558 ms --- 192.168.122.102 ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2000ms rtt min/avg/max/mdev = 0.343/0.434/0.558/0.092 ms ---- Now we need to make sure we can communicate with the machines by their name. If you have a DNS server, add additional entries for the two -machines. Otherwise, you'll need to add the machines to '/etc/hosts' . -Below are the entries for my cluster nodes: +machines. Otherwise, you'll need to add the machines to +/etc/hosts+ +on both nodes. Below are the entries for my cluster nodes: -[source,C] ---- -# grep pcmk /etc/hosts +[root@pcmk-1 ~]# grep pcmk /etc/hosts 192.168.122.101 pcmk-1.clusterlabs.org pcmk-1 192.168.122.102 pcmk-2.clusterlabs.org pcmk-2 ---- We can now verify the setup by again using ping: -[source,C] ---- -# ping -c 3 pcmk-2 +[root@pcmk-1 ~]# ping -c 3 pcmk-2 PING pcmk-2.clusterlabs.org (192.168.122.101) 56(84) bytes of data. 64 bytes from pcmk-1.clusterlabs.org (192.168.122.101): icmp_seq=1 ttl=64 time=0.164 ms 64 bytes from pcmk-1.clusterlabs.org (192.168.122.101): icmp_seq=2 ttl=64 time=0.475 ms 64 bytes from pcmk-1.clusterlabs.org (192.168.122.101): icmp_seq=3 ttl=64 time=0.186 ms --- pcmk-2.clusterlabs.org ping statistics --- 3 packets transmitted, 3 received, 0% packet loss, time 2001ms rtt min/avg/max/mdev = 0.164/0.275/0.475/0.141 ms ---- === Configure SSH === SSH is a convenient and secure way to copy files and perform commands remotely. For the purposes of this guide, we will create a key without a password (using the -N option) so that we can perform remote actions without being prompted. (((SSH))) [WARNING] ========= -Unprotected SSH keys, those without a password, are not recommended for servers exposed to the outside world. +Unprotected SSH keys (those without a password) are not recommended for servers exposed to the outside world. We use them here only to simplify the demo. ========= Create a new key and allow anyone with that key to log in: .Creating and Activating a new SSH Key -[source,C] ---- -# ssh-keygen -t dsa -f ~/.ssh/id_dsa -N "" +[root@pcmk-1 ~]# ssh-keygen -t dsa -f ~/.ssh/id_dsa -N "" Generating public/private dsa key pair. Your identification has been saved in /root/.ssh/id_dsa. Your public key has been saved in /root/.ssh/id_dsa.pub. The key fingerprint is: 91:09:5c:82:5a:6a:50:08:4e:b2:0c:62:de:cc:74:44 root@pcmk-1.clusterlabs.org The key's randomart image is: +--[ DSA 1024]----+ |==.ooEo.. | |X O + .o o | | * A + | | + . | | . S | | | | | | | | | +-----------------+ -# cp .ssh/id_dsa.pub .ssh/authorized_keys +[root@pcmk-1 ~]# cp ~/.ssh/id_dsa.pub ~/.ssh/authorized_keys ---- (((Creating and Activating a new SSH Key))) -Install the key on the other nodes and test that you can now run commands -remotely, without being prompted +Install the key on the other node and test that you can now run commands +remotely, without being prompted. .Installing the SSH Key on Another Host -[source,C] ---- -# scp -r .ssh pcmk-2: +[root@pcmk-1 ~]# scp -r ~/.ssh pcmk-2: The authenticity of host 'pcmk-2 (192.168.122.102)' can't be established. RSA key fingerprint is b1:2b:55:93:f1:d9:52:2b:0f:f2:8a:4e:ae:c6:7c:9a. Are you sure you want to continue connecting (yes/no)? yes Warning: Permanently added 'pcmk-2,192.168.122.102' (RSA) to the list of known hosts.root@pcmk-2's password: id_dsa.pub 100% 616 0.6KB/s 00:00 id_dsa 100% 672 0.7KB/s 00:00 known_hosts 100% 400 0.4KB/s 00:00 authorized_keys 100% 616 0.6KB/s 00:00 -# ssh pcmk-2 -- uname -n +[root@pcmk-1 ~]# ssh pcmk-2 -- uname -n pcmk-2 -# ---- -== Cluster Software Installation == - -=== Install the Cluster Software === +== Install the Cluster Software == -Since version 12, Fedora comes with recent versions of everything you -need, so simply fire up a shell on all your nodes and run: +Fedora 17 and later comes with everything you need, so simply fire up a shell +on both nodes and run the following to install pacemaker and command-line +cluster management software: -[source,C] ---- -[ALL] # yum install -y pacemaker pcs +# yum install -y pacemaker pcs ---- -Now install the cluster software on the second node. - -ifdef::pcs[] -=== Install the Cluster Management Software === -The pcs cli command coupled with the pcs daemon creates a cluster -management system capable of managing all aspects of the cluster stack -across all nodes from a single location. - -[source,C] ----- -[ALL] # yum install -y pcs ----- +[IMPORTANT] +=========== +This document will show commands that need to be executed on both nodes +with a simple `#` prompt. Be sure to run them on each node individually. +=========== -Make sure to install the pcs packages on both nodes. -endif::[] +[NOTE] +=========== +This document uses pcs for cluster management. Other alternatives, +such as crmsh, are available, but their syntax +will differ from the examples used here. +=========== -== Setup == +== Configure the Cluster Software == -ifdef::pcs[] === Enable pcs Daemon === Before the cluster can be configured, the pcs daemon must be started and enabled -to boot on startup on each node. This daemon works with the pcs cli command to manage -syncing the corosync configuration across all the nodes in the cluster. +to start at boot time on each node. This daemon works with the pcs command-line interface +to manage synchronizing the corosync configuration across all nodes in the cluster. -Start and enable the daemon by issuing the following commands on each node. +Start and enable the daemon by issuing the following commands on each node: -[source,C] ---- # systemctl start pcsd.service # systemctl enable pcsd.service ---- -Now we need a way for `pcs` to talk to itself on other nodes in the -cluster. This is necessary in order to perform tasks such as syncing -the corosync config, or starting/stopping the cluster on remote nodes - -While `pcs` can be used locally without setting up these user -accounts, this tutorial will make use of these remote access commands, -so we will set a password for the 'hacluster' user. Its probably best -if password is consistent across all the nodes. +The installed packages will create a *hacluster* user with a disabled password. +While this is fine for running `pcs` commands locally, +the account needs a login password in order to perform such tasks as syncing +the corosync configuration, or starting and stopping the cluster on other nodes. -As 'root', run: +This tutorial will make use of such commands, +so now we will set a password for the *hacluster* user, using the same password +on both nodes: -[source,C] ---- # passwd hacluster password: ---- +[NOTE] +=========== Alternatively, to script this process or set the password on a -different machine to the one you're logged into, you can use +different machine from the one you're logged into, you can use the `--stdin` option for `passwd`: -[source,C] ----- -# ssh pcmk-2 -- 'echo redhat1 | passwd --stdin hacluster' ----- - -endif::[] - -ifdef::crmsh[] - -=== Preparation - Multicast === - -Choose a port number and -http://en.wikipedia.org/wiki/Multicast[multi-cast] address. -http://en.wikipedia.org/wiki/Multicast_address[] - -Be sure that the values you chose do not conflict with any existing -clusters you might have. For this document, I have chosen port '4000' -and used '239.255.1.1' as the multi-cast address. - -endif::[] - -=== Notes on Multicast Address Assignment === - -There are several subtle points that often deserve consideration when -choosing/assigning multicast addresses for corosync. -footnote:[This information is borrowed from, the now defunct, http://web.archive.org/web/20101211210054/http://29west.com/docs/THPM/multicast-address-assignment.html] - -. Avoid '224.0.0.x' -+ -Traffic to addresses of the form '224.0.0.x' is often flooded to all -switch ports. This address range is reserved for link-local uses. Many -routing protocols assume that all traffic within this range will be -received by all routers on the network. Hence (at least all Cisco) -switches flood traffic within this range. The flooding behavior -overrides the normal selective forwarding behavior of a -multicast-aware switch (e.g. IGMP snooping, CGMP, etc.). - -. Watch for '32:1' overlap -+ -32 non-contiguous IP multicast addresses are mapped onto each Ethernet -multicast address. A receiver that joins a single IP multicast group -implicitly joins 31 others due to this overlap. Of course, filtering -in the operating system discards undesired multicast traffic from -applications, but NIC bandwidth and CPU resources are nonetheless -consumed discarding it. The overlap occurs in the 5 high-order bits, -so it's best to use the 23 low-order bits to make distinct multicast -streams unique. For example, IP multicast addresses in the range -'239.0.0.0' to '239.127.255.255' all map to unique Ethernet multicast -addresses. However, IP multicast address '239.128.0.0' maps to the -same Ethernet multicast address as '239.0.0.0', '239.128.0.1' maps to -the same Ethernet multicast address as '239.0.0.1', etc. - -. Avoid 'x.0.0.y' and 'x.128.0.y' -+ -Combining the above two considerations, it's best to avoid using IP -multicast addresses of the form 'x.0.0.y' and 'x.128.0.y' since they -all map onto the range of Ethernet multicast addresses that are -flooded to all switch ports. - -. Watch for address assignment conflicts -+ -http://www.iana.org/[IANA] administers -http://www.iana.org/assignments/multicast-addresses[Internet multicast -addresses]. Potential conflicts with Internet multicast address -assignments can be avoided by using -http://www.ietf.org/rfc/rfc3180.txt[GLOP addressing] -(http://en.wikipedia.org/wiki/Autonomous_system_%28Internet%29[AS] -required) or http://www.ietf.org/rfc/rfc2365.txt[administratively -scoped] addresses. Such addresses can be safely used on a network -connected to the Internet without fear of conflict with multicast -sources originating on the Internet. Administratively scoped addresses -are roughly analogous to the unicast address space for -http://www.ietf.org/rfc/rfc1918.txt[private internets]. Site-local -multicast addresses are of the form '239.255.x.y', but can grow down -to '239.252.x.y' if needed. Organization-local multicast addresses are -of the form '239.192-251.x.y', but can grow down to '239.x.y.z' if -needed. - -For a more detailed treatment (57 pages!), see -http://www.cisco.com/en/US/tech/tk828/technologies_white_paper09186a00802d4643.shtml[Cisco's -Guidelines for Enterprise IP Multicast Address Allocation] paper. - -=== Configuring Corosync === - -ifdef::pcs[] - -In the past, at this point in the tutorial an explanation of how to -configure and propagate corosync's /etc/corosync.conf file would be -necessary. Using pcs with the pcs daemon greatly simplifies this -process by generating 'corosync.conf' across all the nodes in the -cluster with a single command. The only thing required to achieve -this is to authenticate as the pcs user 'hacluster' on one of the -nodes in the cluster, and then issue the 'pcs cluster setup' command -with a list of all the node names in the cluster. - -[source,C] ----- -# pcs cluster auth pcmk-1 pcmk-2 +---- +[root@pcmk-1 ~]# ssh pcmk-2 -- 'echo redhat1 | passwd --stdin hacluster' +---- +=========== + +=== Configure Corosync === + +On either node, use `pcs cluster auth` to authenticate as the *hacluster* user: + +---- +[root@pcmk-1 ~]# pcs cluster auth pcmk-1 pcmk-2 Username: hacluster Password: pcmk-1: Authorized pcmk-2: Authorized - -# pcs cluster setup mycluster pcmk-1 pcmk-2 -pcmk-1: Succeeded -pcmk-2: Succeeded ---- -That's it. Corosync is configured across the cluster. If you -received an authorization error for either of those commands, make -sure you setup the 'hacluster' user account and password on every node -in the cluster with the same password. - -endif::[] - -ifdef::crmsh[] - [IMPORTANT] =========== -The instructions below only apply for a machine with a single NIC. If you -have a more complicated setup, you should edit the configuration -manually. -=========== +The version of pcs shipped with Fedora 21 will bind only to +the host's IPv6 address in some circumstances. If you get errors +with `pcs cluster auth`, add this line before the first *server.run* line in ++/usr/lib/pcsd/ssl.rb+ to bind to IPv4 only: -[source,C] ---- -# export ais_port=4000 -# export ais_mcast=239.255.1.1 +webrick_options[:BindAddress] = '0.0.0.0' ---- -Next we automatically determine the hosts address. By not using the full -address, we make the configuration suitable to be copied to other nodes. - -[source,Bash] +And restart pcsd: ---- -export ais_addr=`ip addr | grep "inet " | tail -n 1 | awk '{print $4}' | sed s/255/0/g` +[root@pcmk-1 ~]# systemctl restart pcsd ---- -Display and verify the configuration options +This is a temporary workaround that will get removed if the pcsd +package is later updated. +=========== -[source,Bash] +Next, use `pcs cluster setup` to generate and synchronize the corosync +configuration: ---- -# env | grep ais_ -ais_mcast=239.255.1.1 -ais_port=4000 -ais_addr=192.168.122.0 +[root@pcmk-1 ~]# pcs cluster setup --name mycluster pcmk-1 pcmk-2 +Shutting down pacemaker/corosync services... +Redirecting to /bin/systemctl stop pacemaker.service +Redirecting to /bin/systemctl stop corosync.service +Killing any remaining services... +Removing all cluster configuration files... +pcmk-1: Succeeded +pcmk-2: Succeeded ---- -Once you're happy with the chosen values, update the Corosync -configuration +If you received an authorization error for either of those commands, make +sure you configured the *hacluster* user account on each node +with the same password. -[source,C] ----- -# cp /etc/corosync/corosync.conf.example /etc/corosync/corosync.conf -# sed -i.bak "s/.*mcastaddr:.*/mcastaddr:\ $ais_mcast/g" /etc/corosync/corosync.conf -# sed -i.bak "s/.*mcastport:.*/mcastport:\ $ais_port/g" /etc/corosync/corosync.conf -# sed -i.bak "s/.*\tbindnetaddr:.*/bindnetaddr:\ $ais_addr/g" /etc/corosync/corosync.conf ----- - -Lastly, you'll need to enable quorum +[NOTE] +====== +Early versions of pcs, such as the one shipped with Fedora 20 and earlier, +require that `--name` be omitted from the above command. -[source,Bash] ------ -cat << END >> /etc/corosync/corosync.conf -quorum { - provider: corosync_votequorum - expected_votes: 2 -} -END ------ +If using a different cluster shell such as crmsh rather than pcs, you must +manually create a corosync.conf and copy it to all nodes. -endif::[] +The pcs command will configure corosync to use UDP unicast transport; if you +choose to use multicast instead, choose a multicast address carefully. +footnote:[For some subtle issues, see the now-defunct http://web.archive.org/web/20101211210054/http://29west.com/docs/THPM/multicast-address-assignment.html or the more detailed treatment in +http://www.cisco.com/c/dam/en/us/support/docs/ip/ip-multicast/ipmlt_wp.pdf[Cisco's +Guidelines for Enterprise IP Multicast Address Allocation] paper.] +====== The final /etc/corosync.conf configuration on each node should look something like the sample in Appendix B, Sample Corosync Configuration. - -[IMPORTANT] -=========== -Pacemaker used to obtain membership and quorum from a custom Corosync plugin. -This plugin also had the capability to start Pacemaker automatically when Corosync was started. - -Neither behavior is possible with Corosync 2.0 and beyond as support for plugins was removed. -Instead, Pacemaker must be started as a separate service. - -Also, since Pacemaker made use of the plugin for message routing, a node using the plugin (Corosync prior to 2.0) cannot talk to one that isn't (Corosync 2.0+). -Rolling upgrades between these versions are therefor not possible and an alternate strategy footnote:[http://www.clusterlabs.org/doc/en-US/Pacemaker/1.1/html/Pacemaker_Explained/ap-upgrade.html] must be used. -=========== - -ifdef::crmsh[] -=== Propagate the Configuration === - -Now we need to copy the changes so far to the other node: - -[source,C] ----- -# for f in /etc/corosync/corosync.conf /etc/hosts; do scp $f pcmk-2:$f ; done -corosync.conf 100% 1528 1.5KB/s 00:00 -hosts 100% 281 0.3KB/s 00:00 -# ----- -endif::[] +[NOTE] +====== +With versions of Corosync before 2.0, Pacemaker could obtain membership and +quorum from a custom Corosync plugin. This plugin also had the capability to +start Pacemaker automatically when Corosync was started. +Neither behavior is possible with Corosync 2.0 and later, as support for +plugins was removed. + +Because Pacemaker made use of the plugin for message routing, a cluster node +using an older Corosync cannot talk to one using Corosync 2.0 or later. +Rolling upgrades between these versions are therefore not possible, and an +alternate strategy +footnote:[http://www.clusterlabs.org/doc/en-US/Pacemaker/1.1/html/Pacemaker_Explained/ap-upgrade.html] +must be used. +====== diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Intro.txt b/doc/Clusters_from_Scratch/en-US/Ch-Intro.txt index a3a032994d..ca81b217f7 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Intro.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Intro.txt @@ -1,168 +1,164 @@ = Read-Me-First = == The Scope of this Document == Computer clusters can be used to provide highly available services or resources. The redundancy of multiple machines is used to guard against failures of many types. This document will walk through the installation and setup of simple -clusters using the Fedora distribution, version 20. +clusters using the &DISTRO; distribution, version &DISTRO_VERSION;. The clusters described here will use Pacemaker and Corosync to provide resource management and messaging. Required packages and modifications to their configuration files are described along with the use of the Pacemaker command line tool for generating the XML used for cluster control. Pacemaker is a central component and provides the resource management required in these systems. This management includes detecting and recovering from the failure of various nodes, resources and services under its control. When more in depth information is required and for real world usage, please refer to the http://www.clusterlabs.org/doc/[Pacemaker Explained] manual. == 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 +(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 STONITH for ensuring data integrity + * Supports fencing (aka. STONITH) for ensuring data integrity * Supports large and small clusters - * Supports both quorate and resource driven clusters + * Supports both quorate and resource-driven clusters * 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 service types ** 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 management tools. == Pacemaker Architecture == At the highest level, the cluster is made up of three pieces: - * Non-cluster aware components. These pieces - include the resources themselves, scripts that start, stop and - monitor them, and also a local daemon that masks the differences + * Non-cluster-aware components. These pieces + include the resources themselves; scripts that start, stop and + monitor them; and a local daemon that masks the differences between the different standards these scripts implement. * Resource management. Pacemaker provides the brain that processes and reacts to events regarding the cluster. These events include nodes joining or leaving the cluster; resource events caused by - failures, maintenance, scheduled activities; and other + failures, maintenance and scheduled activities; and other administrative actions. Pacemaker will compute the ideal state of the cluster and plot a path to achieve it after any of these events. This may include moving resources, stopping nodes and even forcing them offline with remote power switches. - * Low level infrastructure. Projects like Corosync, CMAN and + * Low-level infrastructure. Projects like Corosync, CMAN and Heartbeat provide reliable messaging, membership and quorum information about the cluster. 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. -] +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, but there seems little interest in this.] Due to past standardization within the cluster filesystem community, -they make use of a common distributed lock manager which makes use of -Corosync for its messaging and membership capabilities (which nodes +cluster filesystems make use of a common distributed lock manager, which makes +use of Corosync for its messaging and membership capabilities (which nodes are up/down) and Pacemaker for fencing services. .The Pacemaker Stack image::images/pcmk-stack.png["The Pacemaker stack",width="10cm",height="7.5cm",align="center"] === Internal Components === Pacemaker itself is composed of five key components: - * CIB (aka. Cluster Information Base) - * CRMd (aka. Cluster Resource Management daemon) - * LRMd (aka. Local Resource Management daemon) - * PEngine (aka. PE or Policy Engine) - * STONITHd + * Cluster Information Base (CIB) + * Cluster Resource Management daemon (CRMd) + * Local Resource Management daemon (LRMd) + * Policy Engine (PEngine or PE) + * Fencing daemon (STONITHd) .Internal Components image::images/pcmk-internals.png["Subsystems of a Pacemaker cluster",align="center",scaledwidth="65%"] 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 +This list of instructions is then fed to the Designated +Controller (DC). 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 +elected CRMd process (or the node it is on) fail, a new one is quickly established. The DC carries out the PEngine's instructions in the required order by -passing them to either the LRMd (Local Resource Management daemon) or +passing them to either the Local Resource Management daemon (LRMd) 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 +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. +its clients simply request a node be fenced, and it does the rest. == Types of Pacemaker Clusters == -Pacemaker makes no assumptions about your environment, this allows it +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. diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Shared-Storage.txt b/doc/Clusters_from_Scratch/en-US/Ch-Shared-Storage.txt index f6b50d91ee..b5c87f5ec9 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Shared-Storage.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Shared-Storage.txt @@ -1,778 +1,509 @@ -= Replicated Storage with DRBD = += Replicate Storage Using DRBD = -== Background == Even if you're serving up static websites, having to manually synchronize the contents of that website to all the machines in the cluster is not ideal. For dynamic websites, such as a wiki, it's not even an option. Not -everyone care afford network-attached storage but somehow the data needs -to be kept in sync. Enter DRBD which can be thought of as network based -RAID-1. See http://www.drbd.org/ for more details. +everyone care afford network-attached storage, but somehow the data needs +to be kept in sync. + +Enter DRBD, which can be thought of as network-based RAID-1. +footnote:[See http://www.drbd.org/ for details.] == Install the DRBD Packages == -Since its inclusion in the upstream 2.6.33 kernel, everything needed -to use DRBD has shiped with Fedora since version 13. All you need to -do is install it: +DRBD itself is included in the upstream kernel, +footnote:[Since version 2.6.33] +but we do need some utilities to use it effectively. On both nodes, run: -[source,C] +---- # yum install -y drbd-pacemaker drbd-udev +---- -..... -Loaded plugins: langpacks, presto, refresh-packagekit -Resolving Dependencies ---> Running transaction check ----> Package drbd-pacemaker.x86_64 0:8.3.11-5.fc17 will be installed ---> Processing Dependency: drbd-utils = 8.3.11-5.fc17 for package: drbd-pacemaker-8.3.11-5.fc17.x86_64 ----> Package drbd-udev.x86_64 0:8.3.11-5.fc17 will be installed ---> Running transaction check ----> Package drbd-utils.x86_64 0:8.3.11-5.fc17 will be installed ---> Finished Dependency Resolution - -Dependencies Resolved - -====================================================================================== - Package Arch Version Repository Size -====================================================================================== -Installing: - drbd-pacemaker x86_64 8.3.11-5.fc17 updates-testing 22 k - drbd-udev x86_64 8.3.11-5.fc17 updates-testing 6.4 k -Installing for dependencies: - drbd-utils x86_64 8.3.11-5.fc17 updates-testing 183 k - -Transaction Summary -====================================================================================== -Install 2 Packages (+1 Dependent package) - -Total download size: 212 k -Installed size: 473 k -Downloading Packages: -(1/3): drbd-pacemaker-8.3.11-5.fc17.x86_64.rpm | 22 kB 00:00 -(2/3): drbd-udev-8.3.11-5.fc17.x86_64.rpm | 6.4 kB 00:00 -(3/3): drbd-utils-8.3.11-5.fc17.x86_64.rpm | 183 kB 00:00 --------------------------------------------------------------------------------------- -Total 293 kB/s | 212 kB 00:00 -Running Transaction Check -Running Transaction Test -Transaction Test Succeeded -Running Transaction - Installing : drbd-utils-8.3.11-5.fc17.x86_64 1/3 - Installing : drbd-pacemaker-8.3.11-5.fc17.x86_64 2/3 - Installing : drbd-udev-8.3.11-5.fc17.x86_64 3/3 - Verifying : drbd-pacemaker-8.3.11-5.fc17.x86_64 1/3 - Verifying : drbd-udev-8.3.11-5.fc17.x86_64 2/3 - Verifying : drbd-utils-8.3.11-5.fc17.x86_64 3/3 - -Installed: - drbd-pacemaker.x86_64 0:8.3.11-5.fc17 drbd-udev.x86_64 0:8.3.11-5.fc17 - -Dependency Installed: - drbd-utils.x86_64 0:8.3.11-5.fc17 - -Complete! -..... - -== Configure DRBD == - -Before we configure DRBD, we need to set aside some disk for it to use. - -=== Create A Partition for DRBD === +== Allocate a Disk Volume for DRBD == -If you have more than 1Gb free, feel free to use it. For this guide -however, 1Gb is plenty of space for a single html file and sufficient for -later holding the GFS2 metadata. +DRBD will need its own block device on each node. This can be +a physical disk partition or logical volume, of whatever size +you need for your data. For this document, we will use a +1GiB logical volume, which is more than sufficient for a single HTML file and +(later) GFS2 metadata. -[source,C] ---- -# vgdisplay | grep -e Name -e Free - VG Name vg_pcmk1 - Free PE / Size 31 / 992.00 MiB -# lvs - LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert - lv_root vg_pcmk1 -wi-ao-- 8.56g - lv_swap vg_pcmk1 -wi-ao-- 960.00m -# lvcreate -n drbd-demo -L 1G vg_pcmk1 +[root@pcmk-1 ~]# vgdisplay | grep -e Name -e Free + VG Name fedora-server_pcmk-1 + Free PE / Size 511 / 2.00 GiB +[root@pcmk-1 ~]# lvcreate --name drbd-demo --size 1G fedora-server_pcmk-1 Logical volume "drbd-demo" created -# lvs - LV VG Attr LSize Pool Origin Data% Move Log Copy% Convert - drbd-demo vg_pcmk1 -wi-a--- 1.00G - lv_root vg_pcmk1 -wi-ao-- 8.56g - lv_swap vg_pcmk1 -wi-ao-- 960.00m +[root@pcmk-1 ~]# lvs + LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert + drbd-demo fedora-server_pcmk-1 -wi-a----- 1.00g + root fedora-server_pcmk-1 -wi-ao---- 5.00g + swap fedora-server_pcmk-1 -wi-ao---- 1.00g ---- -Repeat this on the second node, be sure to use the same size partition. +Repeat this on the second node, making sure to use the same size. -[source,C] ---- -# ssh pcmk-2 -- lvs -LV VG Attr LSize Origin Snap% Move Log Copy% Convert - lv_root vg_pcmk1 -wi-ao-- 8.56g - lv_swap vg_pcmk1 -wi-ao-- 960.00m -# ssh pcmk-2 -- lvcreate -n drbd-demo -L 1G vg_pcmk1 +[root@pcmk-1 ~]# ssh pcmk-2 -- lvcreate --name drbd-demo --size 1G fedora-server_pcmk-2 Logical volume "drbd-demo" created -# ssh pcmk-2 -- lvs -LV VG Attr LSize Origin Snap% Move Log Copy% Convert - drbd-demo vg_pcmk1 -wi-a--- 1.00G - lv_root vg_pcmk1 -wi-ao-- 8.56g - lv_swap vg_pcmk1 -wi-ao-- 960.00m ---- -=== Write the DRBD Config === +== Configure DRBD == There is no series of commands for building a DRBD configuration, so simply -copy the configuration below to /etc/drbd.conf - -Detailed information on the directives used in this configuration (and -other alternatives) is available from -http://www.drbd.org/users-guide/ch-configure.html - -[WARNING] -========= - -Be sure to use the names and addresses of your nodes if they differ from -the ones used in this guide. - -========= +run this on both nodes to use this sample configuration: -.... -global { - usage-count yes; -} -common { - protocol C; -} +---- +# cat </etc/drbd.d/wwwdata.res resource wwwdata { + protocol C; meta-disk internal; - device /dev/drbd1; + device /dev/drbd1; syncer { verify-alg sha1; } net { allow-two-primaries; } on pcmk-1 { - disk /dev/vg_pcmk1/drbd-demo; + disk /dev/fedora-server_pcmk-1/drbd-demo; address 192.168.122.101:7789; } on pcmk-2 { - disk /dev/vg_pcmk1/drbd-demo; + disk /dev/fedora-server_pcmk-2/drbd-demo; address 192.168.122.102:7789; } } -.... +END +---- + +[IMPORTANT] +========= +Edit the file to use the hostnames, IP addresses and logical volume paths +of your nodes if they differ from the ones used in this guide. +========= [NOTE] ======= +Detailed information on the directives used in this configuration (and +other alternatives) is available at +http://www.drbd.org/users-guide/ch-configure.html -TODO: Explain the reason for the allow-two-primaries option - +The *allow-two-primaries* option would not normally be used in +an active/passive cluster. We are adding it here for the convenience +of changing to an active/active cluster later. ======= -=== Initialize and Load DRBD === +== Initialize DRBD == + +With the configuration in place, we can now get DRBD running. -With the configuration in place, we can now perform the DRBD -initialization +These commands create the local metadata for the DRBD resource, +ensure the DRBD kernel module is loaded, and bring up the DRBD resource. +Run them on one node: -[source,C] ---- # drbdadm create-md wwwdata -Writing meta data... initializing activity log -NOT initialized bitmap +NOT initializing bitmap +Writing meta data... New drbd meta data block successfully created. -success +# modprobe drbd +# drbdadm up wwwdata ---- -Now load the DRBD kernel module and confirm that everything is sane +We can confirm DRBD's status on this node: -[source,C] ---- -# modprobe drbd -# drbdadm up wwwdata # cat /proc/drbd -version: 8.3.11 (api:88/proto:86-96) -srcversion: 0D2B62DEDB020A425130935 +version: 8.4.5 (api:1/proto:86-101) +srcversion: 153833F4A69E341D3F3E707 - 1: cs:Connected ro:Secondary/Secondary ds:Inconsistent/Inconsistent C r----- - ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:1015740 + 1: cs:WFConnection ro:Secondary/Unknown ds:Inconsistent/DUnknown C r----s + ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:1048508 ---- -Repeat on the second node +Because we have not yet initialized the data, this node's data +is marked as *Inconsistent*. Because we have not yet initialized +the second node, the local state is *WFConnection* (waiting for connection), +and the partner node's status is marked as *Unknown*. + +Now, repeat the above commands on the second node. This time, +when we check the status, it shows: -[source,C] ---- -# ssh pcmk-2 -- drbdadm --force create-md wwwdata -Writing meta data... -initializing activity log -NOT initialized bitmap -New drbd meta data block successfully created. -success -# ssh pcmk-2 -- modprobe drbd -WARNING: Deprecated config file /etc/modprobe.conf, all config files belong into /etc/modprobe.d/. -# ssh pcmk-2 -- drbdadm up wwwdata -# ssh pcmk-2 -- cat /proc/drbd -version: 8.3.11 (api:88/proto:86-96) -srcversion: 0D2B62DEDB020A425130935 +# cat /proc/drbd +version: 8.4.5 (api:1/proto:86-101) +srcversion: 153833F4A69E341D3F3E707 1: cs:Connected ro:Secondary/Secondary ds:Inconsistent/Inconsistent C r----- - ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:1015740 + ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:1048508 ---- -Now we need to tell DRBD which set of data to use. Since both sides -contain garbage, we can run the following on pcmk-1: +You can see the state has changed to *Connected*, meaning the two DRBD nodes +are communicating properly, and both nodes are in *Secondary* role +with *Inconsistent* data. + +To make the data consistent, we need to tell DRBD which node should be +considered to have the correct data. In this case, since we are creating +a new resource, both have garbage, so we'll just pick pcmk-1 +and run this command on it: -[source,C] ---- -# drbdadm -- --overwrite-data-of-peer primary wwwdata -# cat /proc/drbd -version: 8.3.11 (api:88/proto:86-96) -srcversion: 0D2B62DEDB020A425130935 +[root@pcmk-1 ~]# drbdadm primary --force wwwdata +---- + +[NOTE] +====== +In DRBD 8.3 and earlier, the equivalent command is: +---- +[root@pcmk-1 ~]# drbdadm -- --overwrite-data-of-peer primary wwwdata +---- +====== + +If we check the status immediately, we'll see something like this: +---- +[root@pcmk-1 ~]# cat /proc/drbd +version: 8.4.5 (api:1/proto:86-101) +srcversion: 153833F4A69E341D3F3E707 1: cs:SyncSource ro:Primary/Secondary ds:UpToDate/Inconsistent C r----- - ns:8064 nr:0 dw:0 dr:8728 al:0 bm:0 lo:0 pe:1 ua:0 ap:0 ep:1 wo:f oos:1007804 - [>....................] sync'ed: 0.9% (1007804/1015740)K - finish: 0:12:35 speed: 1,320 (1,320) K/sec + ns:2872 nr:0 dw:0 dr:3784 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:1045636 + [>....................] sync'ed: 0.4% (1045636/1048508)K + finish: 0:10:53 speed: 1,436 (1,436) K/sec ---- -After a while, the sync should finish and you'll see: +We can see that this node has the *Primary* role, the partner node has +the *Secondary* role, this node's data is now considered *UpToDate*, +the partner node's data is still *Inconsistent*, and a progress bar +shows how far along the partner node is in synchronizing the data. -[source,C] +After a while, the sync should finish, and you'll see something like: ---- -# cat /proc/drbd -version: 8.3.11 (api:88/proto:86-96) -srcversion: 0D2B62DEDB020A425130935 +[root@pcmk-1 ~]# cat /proc/drbd +version: 8.4.5 (api:1/proto:86-101) +srcversion: 153833F4A69E341D3F3E707 1: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r----- - ns:1015740 nr:0 dw:0 dr:1016404 al:0 bm:62 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0 + ns:1048508 nr:0 dw:0 dr:1049420 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:f oos:0 ---- -pcmk-1 is now in the Primary state which allows it to be written to. -Which means it's a good point at which to create a filesystem and populate -it with some data to serve up via our WebSite resource. +Both sets of data are now *UpToDate*, and we can proceed to creating +and populating a filesystem for our WebSite resource's documents. +== Populate the DRBD Disk == -=== Populate DRBD with Data === +On the node with the primary role (pcmk-1 in this example), +create a filesystem on the DRBD device: -[source,C] ---- -# mkfs.ext4 /dev/drbd1 -mke2fs 1.42 (29-Nov-2011) -Filesystem label= -OS type: Linux -Block size=4096 (log=2) -Fragment size=4096 (log=2) -Stride=0 blocks, Stripe width=0 blocks -63488 inodes, 253935 blocks -12696 blocks (5.00%) reserved for the super user -First data block=0 -Maximum filesystem blocks=260046848 -8 block groups -32768 blocks per group, 32768 fragments per group -7936 inodes per group -Superblock backups stored on blocks: +[root@pcmk-1 ~]# mkfs.ext4 /dev/drbd1 +mke2fs 1.42.11 (09-Jul-2014) +Creating filesystem with 262127 4k blocks and 65536 inodes +Filesystem UUID: 26879260-9077-4d6d-ad69-7d31d3d8d8d4 +Superblock backups stored on blocks: 32768, 98304, 163840, 229376 -Allocating group tables: done -Writing inode tables: done +Allocating group tables: done +Writing inode tables: done Creating journal (4096 blocks): done Writing superblocks and filesystem accounting information: done ---- -Now mount the newly created filesystem so we can create our index file +[NOTE] +==== +In this example, we create an ext4 filesystem with no special options. +In a production environment, you should choose a filesystem type and +options that are suitable for your application. +==== + +Mount the newly created filesystem, populate it with our web document, +then unmount it (the cluster will handle mounting and unmounting it later): -[source,C] ---- -# mount /dev/drbd1 /mnt/ -# cat <<-END >/mnt/index.html +[root@pcmk-1 ~]# mount /dev/drbd1 /mnt +[root@pcmk-1 ~]# cat <<-END >/mnt/index.html - My Test Site - drbd + My Test Site - DRBD END -# umount /dev/drbd1 +[root@pcmk-1 ~]# umount /dev/drbd1 ---- -== Configure the Cluster for DRBD == - -ifdef::pcs[] +== Configure the Cluster for the DRBD device == -One handy feature pcs has is the ability to queue up several changes +One handy feature `pcs` has is the ability to queue up several changes into a file and commit those changes atomically. To do this, start by -populating the file with the current raw xml config from the cib. This -can be done using the following command. +populating the file with the current raw XML config from the CIB. -[source,C] ---- # pcs cluster cib drbd_cfg ---- -Now using the pcs -f option, make changes to the configuration saved -in the drbd_cfg file. These changes will not be seen by the cluster until -the drbd_cfg file is pushed into the live cluster's cib later on. +Using the `pcs -f` option, make changes to the configuration saved +in the +drbd_cfg+ file. These changes will not be seen by the cluster until +the +drbd_cfg+ file is pushed into the live cluster's CIB later. -//// -source,C doesn't do well with \'s -//// +Here, we create a cluster resource for the DRBD device, and an additional _clone_ +resource to allow the resource to run on both nodes at the same time. ---- -# pcs -f drbd_cfg resource create WebData ocf:linbit:drbd \ +[root@pcmk-1 ~]# pcs -f drbd_cfg resource create WebData ocf:linbit:drbd \ drbd_resource=wwwdata op monitor interval=60s -# pcs -f drbd_cfg resource master WebDataClone WebData \ +[root@pcmk-1 ~]# pcs -f drbd_cfg resource master WebDataClone WebData \ master-max=1 master-node-max=1 clone-max=2 clone-node-max=1 \ notify=true ----- -[source,C] ----- -# pcs -f drbd_cfg resource show - ClusterIP (ocf::heartbeat:IPaddr2) Started - WebSite (ocf::heartbeat:apache) Started +[root@pcmk-1 ~]# pcs -f drbd_cfg resource show + ClusterIP (ocf::heartbeat:IPaddr2): Started + WebSite (ocf::heartbeat:apache): Started Master/Slave Set: WebDataClone [WebData] - Stopped: [ WebData:0 WebData:1 ] + Stopped: [ pcmk-1 pcmk-2 ] ---- -After you are satisfied with all the changes, you can commit all -the changes at once by pushing the drbd_cfg file into the live -cib. +After you are satisfied with all the changes, you can commit +them all at once by pushing the drbd_cfg file into the live CIB. -[source,C] ---- -# pcs cluster push cib drbd_cfg +[root@pcmk-1 ~]# pcs cluster cib-push drbd_cfg CIB updated +---- -# pcs status +[NOTE] +==== +Early versions of `pcs` required `push cib` in place of `cib-push` above. +==== -Last updated: Fri Sep 14 12:19:49 2012 -Last change: Fri Sep 14 12:19:13 2012 via cibadmin on pcmk-1 +Let's see what the cluster did with the new configuration: +---- +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 16:39:43 2014 +Last change: Wed Dec 17 16:39:30 2014 Stack: corosync Current DC: pcmk-2 (2) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -4 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +4 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 - WebSite (ocf::heartbeat:apache): Started pcmk-1 + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 + WebSite (ocf::heartbeat:apache): Started pcmk-1 Master/Slave Set: WebDataClone [WebData] Masters: [ pcmk-1 ] Slaves: [ pcmk-2 ] ----- -endif::[] - -ifdef::crmsh[] -One handy feature of the crm shell is that you can use it in -interactive mode to make several changes atomically. - -First we launch the shell. The prompt will change to indicate you're -in interactive mode. - -[source,C] ----- -# crm -crm(live) # ----- - -Next we must create a working copy of the current configuration. This is -where all our changes will go. The cluster will not see any of them until -we say it's ok. Notice again how the prompt changes, this time to indicate -that we're no longer looking at the live cluster. - -[source,C] ----- -cib crm(live) # cib new drbd -INFO: drbd shadow CIB created -crm(drbd) # ----- - -Now we can create our DRBD clone and display the revised configuration. - -[source,C] ----- -crm(drbd) # configure primitive WebData ocf:linbit:drbd params drbd_resource=wwwdata \ - op monitor interval=60s -crm(drbd) # configure ms WebDataClone WebData meta master-max=1 master-node-max=1 \ - clone-max=2 clone-node-max=1 notify=true -crm(drbd) # configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -primitive WebData ocf:linbit:drbd \ - params drbd_resource="wwwdata" \ - op monitor interval="60s" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -ms WebDataClone WebData \ - meta master-max="1" master-node-max="1" clone-max="2" clone-node-max="1" notify="true" -location prefer-pcmk-1 WebSite 50: pcmk-1 -colocation website-with-ip inf: WebSite ClusterIP -order apache-after-ip inf: ClusterIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" \ - last-lrm-refresh="1333446866" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" ----- - -Once we're happy with the changes, we can tell the cluster to start using -them and use crm_mon to check everything is functioning. - -[source,C] ----- -crm(drbd) # cib commit drbd -INFO: commited 'drbd' shadow CIB to the cluster -crm(drbd) # quit -bye -# crm_mon -1 -============ -Last updated: Tue Apr 3 13:50:01 2012 -Last change: Tue Apr 3 13:49:46 2012 via crm_shadow on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -4 Resources configured. -============ -Online: [ pcmk-1 pcmk-2 ] +PCSD Status: + pcmk-1: Online + pcmk-2: Online - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 - WebSite (ocf::heartbeat:apache): Started pcmk-1 - Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-1 ] - Slaves: [ pcmk-2 ] +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -endif::[] -[NOTE] -======= +We can see that *WebDataClone* (our DRBD device) is running as master (DRBD's +primary role) on *pcmk-1* and slave (DRBD's secondary role) on *pcmk-2*. -TODO: Include details on adding a second DRBD resource +[IMPORTANT] +==== +The resource agent should load the DRBD module when needed if it's not already +loaded. If that does not happen, configure your operating system to load the +module at boot time. For Fedora 21, you would run this on both nodes: +---- +# echo drbd >/etc/modules-load.d/drbd.conf +---- +==== -======= +== Configure the Cluster for the Filesystem == -Now that DRBD is functioning we can configure a Filesystem resource to -use it. In addition to the filesystem's definition, we also need to +Now that we have a working DRBD device, we need to mount its filesystem. + +In addition to defining the filesystem, we also need to tell the cluster where it can be located (only on the DRBD Primary) and when it is allowed to start (after the Primary was promoted). -ifdef::pcs[] -We are going to take a shortcut when creating the resource this time though. -Instead of explicitly saying we want the 'ocf:heartbeat:Filesystem' script, we -are only going to ask for 'Filesystem'. We can do this because we know there is only -one resource script named 'Filesystem' available to pacemaker, and that pcs is smart -enough to fill in the 'ocf:heartbeat' portion for us correctly in the configuration. -If there were multiple 'Filesystem' scripts from different ocf providers, we would need -to specify the exact one we wanted to use. +We are going to take a shortcut when creating the resource this time. +Instead of explicitly saying we want the *ocf:heartbeat:Filesystem* script, we +are only going to ask for *Filesystem*. We can do this because we know there is only +one resource script named *Filesystem* available to pacemaker, and that pcs is smart +enough to fill in the *ocf:heartbeat:* portion for us correctly in the configuration. +If there were multiple *Filesystem* scripts from different OCF providers, we would need +to specify the exact one we wanted. -Once again we will queue up our changes to a file and then push the +Once again, we will queue our changes to a file and then push the new configuration to the cluster as the final step. ---- -# pcs cluster cib fs_cfg -# pcs -f fs_cfg resource create WebFS Filesystem \ - device="/dev/drbd/by-res/wwwdata" directory="/var/www/html" \ +[root@pcmk-1 ~]# pcs cluster cib fs_cfg +[root@pcmk-1 ~]# pcs -f fs_cfg resource create WebFS Filesystem \ + device="/dev/drbd1" directory="/var/www/html" \ fstype="ext4" ----- -[source,C] ----- -# pcs -f fs_cfg constraint colocation add WebFS WebDataClone INFINITY with-rsc-role=Master -# pcs -f fs_cfg constraint order promote WebDataClone then start WebFS +[root@pcmk-1 ~]# pcs -f fs_cfg constraint colocation add WebFS with WebDataClone INFINITY with-rsc-role=Master +[root@pcmk-1 ~]# pcs -f fs_cfg constraint order promote WebDataClone then start WebFS Adding WebDataClone WebFS (kind: Mandatory) (Options: first-action=promote then-action=start) ---- We also need to tell the cluster that Apache needs to run on the same machine as the filesystem and that it must be active before Apache can start. -[source,C] ---- -# pcs -f fs_cfg constraint colocation add WebSite WebFS INFINITY -# pcs -f fs_cfg constraint order WebFS then WebSite +[root@pcmk-1 ~]# pcs -f fs_cfg constraint colocation add WebSite with WebFS INFINITY +[root@pcmk-1 ~]# pcs -f fs_cfg constraint order WebFS then WebSite +Adding WebFS WebSite (kind: Mandatory) (Options: first-action=start then-action=start) ---- -Now review the updated configuration. +Review the updated configuration. -[source,C] ---- -# pcs -f fs_cfg constraint +[root@pcmk-1 ~]# pcs -f fs_cfg constraint Location Constraints: Ordering Constraints: - start ClusterIP then start WebSite - WebFS then WebSite - promote WebDataClone then start WebFS + start ClusterIP then start WebSite (kind:Mandatory) + promote WebDataClone then start WebFS (kind:Mandatory) + start WebFS then start WebSite (kind:Mandatory) Colocation Constraints: - WebSite with ClusterIP - WebFS with WebDataClone (with-rsc-role:Master) - WebSite with WebFS - -# pcs -f fs_cfg resource show - ClusterIP (ocf::heartbeat:IPaddr2) Started - WebSite (ocf::heartbeat:apache) Started + WebSite with ClusterIP (score:INFINITY) + WebFS with WebDataClone (score:INFINITY) (with-rsc-role:Master) + WebSite with WebFS (score:INFINITY) +[root@pcmk-1 ~]# pcs -f fs_cfg resource show + ClusterIP (ocf::heartbeat:IPaddr2): Started + WebSite (ocf::heartbeat:apache): Started Master/Slave Set: WebDataClone [WebData] Masters: [ pcmk-1 ] Slaves: [ pcmk-2 ] - WebFS (ocf::heartbeat:Filesystem) Stopped ----- - -endif::[] - -ifdef::crmsh[] -Once again we'll use the shell's interactive mode - -[source,C] ----- -# crm -crm(live) # cib new fs -INFO: fs shadow CIB created -crm(fs) # configure primitive WebFS ocf:heartbeat:Filesystem \ - params device="/dev/drbd/by-res/wwwdata" directory="/var/www/html" fstype="ext4" -crm(fs) # configure colocation fs_on_drbd inf: WebFS WebDataClone:Master -crm(fs) # configure order WebFS-after-WebData inf: WebDataClone:promote WebFS:start + WebFS (ocf::heartbeat:Filesystem): Stopped ---- -We also need to tell the cluster that Apache needs to run on the same -machine as the filesystem and that it must be active before Apache can -start. - -[source,C] ----- -crm(fs) # configure colocation WebSite-with-WebFS inf: WebSite WebFS -crm(fs) # configure order WebSite-after-WebFS inf: WebFS WebSite ----- - -Time to review the updated configuration: - -[source,C] ----- -crm(fs) # configure show -node $id="1702537408" pcmk-1 -node $id="1719314624" pcmk-2 -primitive ClusterIP ocf:heartbeat:IPaddr2 \ - params ip="192.168.122.120" cidr_netmask="32" \ - op monitor interval="30s" -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="ext4" -primitive WebSite ocf:heartbeat:apache \ - params configfile="/etc/httpd/conf/httpd.conf" \ - op monitor interval="1min" -ms WebDataClone WebData \ - meta master-max="1" master-node-max="1" clone-max="2" clone-node-max="1" notify="true" -location prefer-pcmk-1 WebSite 50: pcmk-1 -colocation WebSite-with-WebFS inf: WebSite WebFS -colocation fs_on_drbd inf: WebFS WebDataClone:Master -colocation website-with-ip inf: WebSite ClusterIP -order WebFS-after-WebData inf: WebDataClone:promote WebFS:start -order WebSite-after-WebFS inf: WebFS WebSite -order apache-after-ip inf: ClusterIP WebSite -property $id="cib-bootstrap-options" \ - dc-version="1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff" \ - cluster-infrastructure="corosync" \ - stonith-enabled="false" \ - no-quorum-policy="ignore" \ - last-lrm-refresh="1333446866" -rsc_defaults $id="rsc-options" \ - resource-stickiness="100" -op_defaults $id="op-options" \ - timeout="240s" ----- -endif::[] - -After reviewing the new configuration, we again upload it and watch the +After reviewing the new configuration, upload it and watch the cluster put it into effect. -ifdef::pcs[] -[source,C] ---- -# pcs cluster push cib fs_cfg -CIB updated -# pcs status - Last updated: Fri Aug 10 12:47:01 2012 +[root@pcmk-1 ~]# pcs cluster cib-push fs_cfg +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 17:02:45 2014 +Last change: Wed Dec 17 17:02:42 2014 +Stack: corosync +Current DC: pcmk-2 (2) - partition with quorum +Version: 1.1.12-a9c8177 +2 Nodes configured +5 Resources configured - Last change: Fri Aug 10 12:46:55 2012 via cibadmin on pcmk-1 - Stack: corosync - Current DC: pcmk-1 (1) - partition with quorum - Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 - 2 Nodes configured, unknown expected votes - 5 Resources configured. Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 - WebSite (ocf::heartbeat:apache): Started pcmk-1 + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 + WebSite (ocf::heartbeat:apache): Started pcmk-1 Master/Slave Set: WebDataClone [WebData] Masters: [ pcmk-1 ] Slaves: [ pcmk-2 ] - WebFS (ocf::heartbeat:Filesystem): Started pcmk-1 ----- -endif::[] + WebFS (ocf::heartbeat:Filesystem): Started pcmk-1 -ifdef::crmsh[] -[source,C] ----- -crm(fs) # cib commit fs -INFO: commited 'fs' shadow CIB to the cluster -crm(fs) # quit -bye -# crm_mon -1 -============ -Last updated: Tue Apr 3 13:52:21 2012 -Last change: Tue Apr 3 13:52:06 2012 via crm_shadow on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -5 Resources configured. -============ - -Online: [ pcmk-1 pcmk-2 ] +PCSD Status: + pcmk-1: Online + pcmk-2: Online - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-1 - WebSite (ocf::heartbeat:apache): Started pcmk-1 - Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-1 ] - Slaves: [ pcmk-2 ] - WebFS (ocf::heartbeat:Filesystem): Started pcmk-1 +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -endif::[] -=== Testing Migration === +== Test Cluster Failover == -We could shut down the active node again, but another way to safely -simulate recovery is to put the node into what is called "standby -mode". Nodes in this state tell the cluster that they are not allowed -to run resources. Any resources found active there will be moved -elsewhere. This feature can be particularly useful when updating the -resources' packages. +Previously, we used `pcs cluster stop pcmk-1` to stop all cluster +services on *pcmk-1*, failing over the cluster resources, but there is another +way to safely simulate node failure. -Put the local node into standby mode and observe the cluster move all -the resources to the other node. Note also that the node's status will +We can put the node into _standby mode_. Nodes in this state continue to +run corosync and pacemaker but are not allowed to run resources. Any resources +found active there will be moved elsewhere. This feature can be particularly +useful when performing system administration tasks such as updating packages +used by cluster resources. + +Put the active node into standby mode, and observe the cluster move all +the resources to the other node. The node's status will change to indicate that it can no longer host resources. -ifdef::pcs[] -[source,C] ---- -# pcs cluster standby pcmk-1 -# pcs status - -Last updated: Fri Sep 14 12:41:12 2012 -Last change: Fri Sep 14 12:41:08 2012 via crm_attribute on pcmk-1 +[root@pcmk-1 ~]# pcs cluster standby pcmk-1 +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 17:14:05 2014 +Last change: Wed Dec 17 17:14:02 2014 Stack: corosync -Current DC: pcmk-1 (1) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -5 Resources configured. +Current DC: pcmk-2 (2) - partition with quorum +Version: 1.1.12-a9c8177 +2 Nodes configured +5 Resources configured + Node pcmk-1 (1): standby Online: [ pcmk-2 ] Full list of resources: -ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 -WebSite (ocf::heartbeat:apache): Started pcmk-2 + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 + WebSite (ocf::heartbeat:apache): Started pcmk-2 Master/Slave Set: WebDataClone [WebData] Masters: [ pcmk-2 ] - Stopped: [ WebData:1 ] -WebFS (ocf::heartbeat:Filesystem): Started pcmk-2 ----- -endif::[] + Stopped: [ pcmk-1 ] + WebFS (ocf::heartbeat:Filesystem): Started pcmk-2 -ifdef::crmsh[] -[source,C] ----- -# crm node standby -# crm_mon -1 -============ -Last updated: Tue Apr 3 13:59:14 2012 -Last change: Tue Apr 3 13:52:36 2012 via crm_attribute on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -5 Resources configured. -============ - -Node pcmk-1 (1702537408): standby -Online: [ pcmk-2 ] +PCSD Status: + pcmk-1: Online + pcmk-2: Online -ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 -WebSite (ocf::heartbeat:apache): Started pcmk-2 - Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-2 ] - Stopped: [ WebData:1 ] -WebFS (ocf::heartbeat:Filesystem): Started pcmk-2 +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -endif::[] Once we've done everything we needed to on pcmk-1 (in this case nothing, we just wanted to see the resources move), we can allow the node to be a full cluster member again. -ifdef::pcs[] -[source,C] ---- -# pcs cluster unstandby pcmk-1 -# pcs status - -Last updated: Fri Sep 14 12:43:02 2012 -Last change: Fri Sep 14 12:42:57 2012 via crm_attribute on pcmk-1 +[root@pcmk-1 ~]# pcs cluster unstandby pcmk-1 +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +Last updated: Wed Dec 17 17:15:36 2014 +Last change: Wed Dec 17 17:15:33 2014 Stack: corosync -Current DC: pcmk-1 (1) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -5 Resources configured. +Current DC: pcmk-2 (2) - partition with quorum +Version: 1.1.12-a9c8177 +2 Nodes configured +5 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf::heartbeat:apache): Started pcmk-2 + ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 + WebSite (ocf::heartbeat:apache): Started pcmk-2 Master/Slave Set: WebDataClone [WebData] Masters: [ pcmk-2 ] Slaves: [ pcmk-1 ] - WebFS (ocf::heartbeat:Filesystem): Started pcmk-2 ----- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# crm node online -# crm_mon -1 -============ -Last updated: Tue Apr 3 14:00:06 2012 -Last change: Tue Apr 3 14:00:00 2012 via crm_attribute on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -5 Resources configured. -============ + WebFS (ocf::heartbeat:Filesystem): Started pcmk-2 -Online: [ pcmk-1 pcmk-2 ] +PCSD Status: + pcmk-1: Online + pcmk-2: Online - ClusterIP (ocf::heartbeat:IPaddr2): Started pcmk-2 - WebSite (ocf::heartbeat:apache): Started pcmk-2 - Master/Slave Set: WebDataClone [WebData] - Masters: [ pcmk-2 ] - Slaves: [ pcmk-1 ] - WebFS (ocf::heartbeat:Filesystem): Started pcmk-2 +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -endif::[] - -Notice that our resource stickiness settings prevent the services from -migrating back to pcmk-1. +Notice that *pcmk-1* is back to the *Online* state, and that the cluster resources +stay where they are due to our resource stickiness settings configured earlier. diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Stonith.txt b/doc/Clusters_from_Scratch/en-US/Ch-Stonith.txt index 123bd4b361..230a208b52 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Stonith.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Stonith.txt @@ -1,308 +1,139 @@ +[[_what_is_stonith]] = Configure STONITH = -== What Is STONITH == +STONITH (Shoot The Other Node In The Head aka. fencing) protects your data from +being corrupted by rogue nodes or unintended concurrent access. -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 +Just because a node is unresponsive doesn't mean it has stopped 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. - +safe, is to use STONITH to ensure 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 == +== Choose a STONITH Device == -It is crucial that the STONITH device can allow the cluster to -differentiate between a node failure and a network one. +It is crucial that your STONITH device can allow the cluster to +differentiate between a node failure and a network failure. The biggest mistake people make in choosing a STONITH device is to -use remote power switch (such as many on-board IMPI controllers) that +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 == - -ifdef::pcs[] -. Find the correct driver: +pcs stonith list+ - -. Find the parameters associated with the device: +pcs stonith describe + +== Configure the Cluster for STONITH == -. Create a local config to make changes to +pcs cluster cib stonith_cfg+ +. Configure the STONITH device itself to be able to fence your nodes and accept + fencing requests. -. Create the fencing resource using +pcs -f stonith_cfg stonith create - [stonith device options]+ +. Install the STONITH agent(s). To see what packages are available, run `yum + search fence-agents fence-virt`. Be sure to install the package(s) on all + cluster nodes. -. Set stonith-enable to true. +pcs -f stonith_cfg property set stonith-enabled=true+ -endif::[] +. Find the correct STONITH agent script: `pcs stonith list` -ifdef::crmsh[] -. Find the correct driver: +stonith_admin --list-installed+ +. Find the parameters associated with the device: +pcs stonith describe pass:[agent_name]+ -. 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+ +. Create a local copy of the CIB: `pcs cluster cib stonith_cfg` - The output should be XML formatted text containing additional - parameter descriptions. We will endevor to make the output more - friendly in a later version. +. Create the fencing resource: +pcs -f stonith_cfg stonith create pass:[stonith_id + stonith_device_type [stonith_device_options]]+ -. 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::[] +. Enable STONITH in the cluster: `pcs -f stonith_cfg property set stonith-enabled=true` . 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. + 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 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. + *port* parameter, you may also need to set the special + *pcmk_host_argument* parameter. See `man stonithd` for details. -ifdef::crmsh[] -. Upload it into the CIB from the shell: +cib commit stonith+ -endif::[] +. Commit the new configuration: `pcs cluster cib-push stonith_cfg` -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. +. Once the STONITH resource is running, test it (you might want to stop + the cluster on that machine first): +stonith_admin --reboot pass:[nodename]+ == 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 +For this example, assume we have a chassis containing four nodes +and an IPMI device active on 10.0.0.1. Following the steps above +would go something like this: + +Step 1: Configure the IP address, authentication credentials, etc. in the IPMI device itself. + +Step 2: Install the *fence-agents-ipmilan* package on both nodes. -.Obtaining a list of STONITH Parameters +Step 3: Choose the *fence_ipmilan* STONITH agent. -ifdef::pcs[] -[source,C] +Step 4: Obtain the agent's possible parameters: ---- -# pcs stonith describe fence_ipmilan +[root@pcmk-1 ~]# 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 + ipport: TCP/UDP port to use for connection with device + inet6_only: Forces agent to use IPv6 addresses only + ipaddr (required): IP Address or Hostname + passwd_script: Script to retrieve password + method: Method to fence (onoff|cycle) + inet4_only: Forces agent to use IPv4 addresses only + passwd: Login password or passphrase + lanplus: Use Lanplus to improve security of connection + auth: IPMI Lan Auth type. 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 + action (required): Fencing Action + login: Login Name verbose: Verbose mode + debug: Write debug information to given file + version: Display version information and exit + help: Display help and exit + power_wait: Wait X seconds after issuing ON/OFF + login_timeout: Wait X seconds for cmd prompt after login + power_timeout: Test X seconds for status change after ON/OFF + delay: Wait X seconds before fencing is started + ipmitool_path: Path to ipmitool binary + shell_timeout: Wait X seconds for cmd prompt after issuing command + retry_on: Count of attempts to retry power on + sudo: Use sudo (without password) when calling 3rd party sotfware. + stonith-timeout: How long to wait for the STONITH action to complete per a stonith device. + priority: The priority of the stonith resource. Devices are tried in order of highest priority to lowest. + pcmk_host_map: A mapping of host names to ports numbers for devices that do not support host names. + pcmk_host_list: A list of machines controlled by this device (Optional unless pcmk_host_check=static-list). + pcmk_host_check: How to determine which machines are controlled by the device. ---- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# 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 +Step 5: `pcs cluster cib stonith_cfg` -.Sample STONITH Resource -ifdef::pcs[] +Step 6: Here are example parameters for creating our STONITH resource: ---- -# pcs cluster cib stonith_cfg -# pcs -f stonith_cfg stonith create impi-fencing fence_ipmilan \ +# pcs -f stonith_cfg stonith create ipmi-fencing fence_ipmilan \ pcmk_host_list="pcmk-1 pcmk-2" ipaddr=10.0.0.1 login=testuser \ passwd=acd123 op monitor interval=60s ----- -[source,C] ----- # pcs -f stonith_cfg stonith - impi-fencing (stonith:fence_ipmilan) Stopped + ipmi-fencing (stonith:fence_ipmilan): Stopped ---- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# 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,C] +Steps 7-10: Enable STONITH in the cluster: ---- # 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 +Cluster Properties: + cluster-infrastructure: corosync + cluster-name: mycluster + dc-version: 1.1.12-a9c8177 + have-watchdog: false + stonith-enabled: true ---- -endif::[] -Now push the configuration into the cluster. - -ifdef::pcs[] -[source,C] ----- -# pcs cluster push cib stonith_cfg ----- -endif::[] - -ifdef::crmsh[] -[source,C] ----- -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::[] +Step 11: `pcs cluster cib-push stonith_cfg` diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Tools.txt b/doc/Clusters_from_Scratch/en-US/Ch-Tools.txt index 04de80c886..f3bcd8c700 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Tools.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Tools.txt @@ -1,163 +1,119 @@ = Pacemaker Tools = -== Using Pacemaker Tools == +== Simplify administration using a cluster shell == In the dark past, configuring Pacemaker required the administrator to read and write XML. In true UNIX style, there were also a number of different commands that specialized in different aspects of querying and updating the cluster. All of that has been greatly simplified with the creation of unified command-line shells (and GUIs) that hide all the messy XML scaffolding. These shells take all the individual aspects required for managing and -configuring a cluster, and packs them into one simple to use command +configuring a cluster, and packs them into one simple-to-use command line tool. They even allow you to queue up several changes at once and commit them atomically. There are currently two command-line shells that people use, `pcs` and -`crmsh`. This edition of Clusters from Scratch is based on -+{cli_name}+. Start by taking some time to familiarize yourself with -what it can do. +`crmsh`. This edition of Clusters from Scratch is based on `pcs`. [NOTE] =========== The two shells share many concepts but the scope, layout and syntax does differ, so make sure you read the version of this guide that corresponds to the software installed on your system. =========== -ifdef::pcs[] - [IMPORTANT] =========== Since `pcs` has the ability to manage all aspects of the cluster (both corosync and pacemaker), it requires a specific cluster stack to be in -use, (corosync 2.0 with votequorum + Pacemaker version >= 1.1.8). +use: corosync 2.0 or later with votequorum plus Pacemaker 1.1.8 or later. =========== -[source,C] -# pcs +== Explore pcs == + +Start by taking some time to familiarize yourself with +what `pcs` can do. -..... +---- +[root@pcmk-1 ~]# pcs +Usage: pcs [-f file] [-h] [commands]... Control and configure pacemaker and corosync. Options: -h, --help Display usage and exit -f file Perform actions on file instead of active CIB --debug Print all network traffic and external commands run --version Print pcs version information Commands: cluster Configure cluster options and nodes resource Manage cluster resources stonith Configure fence devices constraint Set resource constraints property Set pacemaker properties status View cluster status config Print full cluster configuration -..... +---- -As you can see, the different aspects of cluster management are broken -up into categories: resource, cluster, stonith, property, constraint, +As you can see, the different aspects of cluster management are separated +into categories: resource, cluster, stonith, property, constraint, and status. To discover the functionality available in each of these -categories, one can issue the command 'pcs help'. Below +categories, one can issue the command +pcs pass:[category] help+. Below is an example of all the options available under the status category. -[source,C] -# pcs status help - -..... +---- +[root@pcmk-1 ~]# pcs status help Usage: pcs status [commands]... View current cluster and resource status Commands: [status] View all information about the cluster and resources resources View current status of cluster resources groups View currently configured groups and their resources cluster View current cluster status corosync View current membership information as seen by corosync nodes [corosync|both|config] View current status of nodes from pacemaker. If 'corosync' is specified, print nodes currently configured in corosync, if 'both' is specified, print nodes from both corosync & pacemaker. If 'config' is specified, print nodes from corosync & pacemaker configuration. pcsd ... Show the current status of pcsd on the specified nodes xml View xml version of status (output from crm_mon -r -1 -X) +---- -..... - -Additionally, if you are interested in the Pacemaker version and -supported cluster stack(s) available with your current Pacemaker -installation, the pacemakerd --features option is available to you. - - -[source,C] -# pacemakerd --features - ------------------- -sys::[pacemakerd --features] ------------------- - -[NOTE] -====== -If the SNMP and/or email options are not listed, then Pacemaker was not -built to support them. This may be by the choice of your distribution or -the required libraries may not have been available. Please contact -whoever supplied you with the packages for more details. -====== - -endif::[] - -ifdef::crmsh[] -pass:[# crm --help] - -The primary tool for monitoring the status of the cluster is crm_mon -(also available as crm status). It can be run in a variety of modes -and has a number of output options. To find out about any of the tools -that come with Pacemaker, simply invoke them with the --help option or -consult the included man pages. Both sets of output are created from -the tool, and so will always be in sync with each other and the tool -itself. - -Additionally, the Pacemaker version and supported cluster stack(s) are -available via the --feature option to pacemakerd. - -[source,C] -# pacemakerd --features - ------------------- -sys::[pacemakerd --features] ------------------- - -[source,C] -# crm_mon --help +Additionally, if you are interested in the version and +supported cluster stack(s) available with your Pacemaker +installation, run: ------------------- -sys::[crm_mon --help] ------------------- +---- +[root@pcmk-1 ~]# pacemakerd --features +Pacemaker 1.1.12 (Build: a9c8177) + Supporting v3.0.9: generated-manpages agent-manpages ascii-docs publican-docs ncurses libqb-logging libqb-ipc upstart systemd nagios corosync-native atomic-attrd acls +---- [NOTE] ====== If the SNMP and/or email options are not listed, then Pacemaker was not -built to support them. This may be by the choice of your distribution or +built to support them. This may be by the choice of your distribution, or the required libraries may not have been available. Please contact whoever supplied you with the packages for more details. ====== -endif::[] diff --git a/doc/Clusters_from_Scratch/en-US/Ch-Verification.txt b/doc/Clusters_from_Scratch/en-US/Ch-Verification.txt index c62cae4ecd..496176388a 100644 --- a/doc/Clusters_from_Scratch/en-US/Ch-Verification.txt +++ b/doc/Clusters_from_Scratch/en-US/Ch-Verification.txt @@ -1,300 +1,154 @@ -= Verify Cluster Installation = += Start and Verify Cluster = -ifdef::pcs[] == Start the Cluster == Now that corosync is configured, it is time to start the cluster. The command below will start corosync and pacemaker on both nodes in the cluster. If you are issuing the start command from a different -node than the one you ran the 'pcs cluster auth' command on earlier, you -must authenticate on current node you are logged into before you will +node than the one you ran the `pcs cluster auth` command on earlier, you +must authenticate on the current node you are logged into before you will be allowed to start the cluster. -[source,C] ---- -# pcs cluster start --all +[root@pcmk-1 ~]# pcs cluster start --all pcmk-1: Starting Cluster... pcmk-2: Starting Cluster... ---- -An alternative to using the 'pcs cluster startall' command -is to issue either of the below commands on each node in the -cluster by hand. +[NOTE] +====== +An alternative to using the `pcs cluster start --all` command +is to issue either of the below command sequences on each node in the +cluster separately: -[source,C] ---- # pcs cluster start Starting Cluster... ---- or -[source,C] ---- # systemctl start corosync.service # systemctl start pacemaker.service ---- +====== -endif::[] +[IMPORTANT] +==== +In this example, we are not enabling the corosync and pacemaker services +to start at boot. If a cluster node fails or is rebooted, you will need to run ++pcs cluster start pass:[nodename]+ (or `--all`) to start the cluster on it. +While you could enable the services to start at boot, requiring a manual +start of cluster services gives you the opportunity to do a post-mortem investigation +of a node failure before returning it to the cluster. +==== == Verify Corosync Installation == -ifdef::crmsh[] -Start Corosync on the first node +First, use `corosync-cfgtool` to check whether cluster communication is happy: -[source,C] ---- -# systemctl start corosync.service ----- -endif::[] - -The first thing to check is if cluster communication is happy, for -that we use `corosync-cfgtool`. - -ifdef::crmsh[] -[source,C] ----- -# corosync-cfgtool -s -Printing ring status. -Local node ID 1702537408 -RING ID 0 - id = 192.168.122.101 - status = ring 0 active with no faults ----- -endif::[] - -ifdef::pcs[] -[source,C] ----- -# corosync-cfgtool -s +[root@pcmk-1 ~]# corosync-cfgtool -s Printing ring status. Local node ID 1 RING ID 0 id = 192.168.122.101 status = ring 0 active with no faults ---- -endif::[] We can see here that everything appears normal with our fixed IP -address, not a 127.0.0.x loopback address, listed as the +id+ and +no -faults+ for the status. +address (not a 127.0.0.x loopback address) listed as the *id*, and *no +faults* for the status. If you see something different, you might want to start by checking the node's network, firewall and selinux configurations. -Next we check the membership and quorum APIs: +Next, check the membership and quorum APIs: -ifdef::pcs[] -[source,C] ---- -# corosync-cmapctl | grep members +[root@pcmk-1 ~]# corosync-cmapctl | grep members runtime.totem.pg.mrp.srp.members.1.ip (str) = r(0) ip(192.168.122.101) runtime.totem.pg.mrp.srp.members.1.join_count (u32) = 1 runtime.totem.pg.mrp.srp.members.1.status (str) = joined runtime.totem.pg.mrp.srp.members.2.ip (str) = r(0) ip(192.168.122.102) runtime.totem.pg.mrp.srp.members.2.join_count (u32) = 1 runtime.totem.pg.mrp.srp.members.2.status (str) = joined -# pcs status corosync +[root@pcmk-1 ~]# pcs status corosync Membership information -------------------------- Nodeid Votes Name 1 1 pcmk-1 (local) 2 1 pcmk-2 ---- You should see both nodes have joined the cluster. -endif::[] - -ifdef::crmsh[] -[source,C] ----- -# corosync-cmapctl | grep members -runtime.totem.pg.mrp.srp.members.1702537408.ip (str) = r(0) ip(192.168.122.101) -runtime.totem.pg.mrp.srp.members.1702537408.join_count (u32) = 1 -runtime.totem.pg.mrp.srp.members.1702537408.status (str) = joined - -# corosync-quorumtool -l -Membership information - -------------------------- - Nodeid Votes Name -1702537408 1 pcmk-1 ----- - -The node see's itself in both locations which is a good sign. - -If the node list is empty when you call `corosync-quorumtool`, then -you've not correctly quorum in 'corosync.conf'. - -With everything looking healthy, we start Corosync on the second node -and run the same communications check. - -[source,C] ----- -# ssh pcmk-2 -- systemctl start corosync.service -# ssh pcmk-2 -- corosync-cfgtool -s -Printing ring status. -Local node ID 1719314624 -RING ID 0 - id = 192.168.122.102 - status = ring 0 active with no faults ----- - -Everything appears to look ok from +pcmk-2+, time to re-run the -membership and quorum checks to see if it shows up there too. - -Again, if you see something different to the above, check for the -usual suspects: network, firewall and selinux. - -[source,C] ----- -# corosync-cmapctl | grep members -runtime.totem.pg.mrp.srp.members.1702537408.ip (str) = r(0) ip(192.168.122.101) -runtime.totem.pg.mrp.srp.members.1702537408.join_count (u32) = 1 -runtime.totem.pg.mrp.srp.members.1702537408.status (str) = joined -runtime.totem.pg.mrp.srp.members.1719314624.ip (str) = r(0) ip(192.168.122.102) -runtime.totem.pg.mrp.srp.members.1719314624.join_count (u32) = 1 -runtime.totem.pg.mrp.srp.members.1719314624.status (str) = joined - -# corosync-quorumtool -l - -Membership information - -------------------------- - Nodeid Votes Name -1702537408 1 pcmk-1 -1719314624 1 pcmk-2 ----- -endif::[] - -All good! == Verify Pacemaker Installation == - -ifdef::pcs[] -Now that we have confirmed that Corosync is functional we can check +Now that we have confirmed that Corosync is functional, we can check the rest of the stack. Pacemaker has already been started, so verify -the necessary processes are running. +the necessary processes are running: -[source,C] ---- -# ps axf +[root@pcmk-1 ~]# ps axf PID TTY STAT TIME COMMAND 2 ? S 0:00 [kthreadd] ...lots of processes... 28019 ? Ssl 0:03 /usr/sbin/corosync 28047 ? Ss 0:00 /usr/sbin/pacemakerd -f 28048 ? Ss 0:00 \_ /usr/libexec/pacemaker/cib 28049 ? Ss 0:00 \_ /usr/libexec/pacemaker/stonithd 28050 ? Ss 0:00 \_ /usr/lib64/heartbeat/lrmd 28051 ? Ss 0:00 \_ /usr/libexec/pacemaker/attrd 28052 ? Ss 0:00 \_ /usr/libexec/pacemaker/pengine 28053 ? Ss 0:00 \_ /usr/libexec/pacemaker/crmd ---- -If that looks ok, check the pcs status output. +If that looks OK, check the `pcs status` output: -[source,C] ---- -# pcs status -Last updated: Fri Sep 14 09:52:25 2012 -Last change: Fri Sep 14 09:51:55 2012 via crmd on pcmk-2 +[root@pcmk-1 ~]# pcs status +Cluster name: mycluster +WARNING: no stonith devices and stonith-enabled is not false +Last updated: Tue Dec 16 16:15:29 2014 +Last change: Tue Dec 16 15:49:47 2014 Stack: corosync Current DC: pcmk-2 (2) - partition with quorum -Version: 1.1.8-1.el7-60a19ed12fdb4d5c6a6b6767f52e5391e447fec0 -2 Nodes configured, unknown expected votes -0 Resources configured. +Version: 1.1.12-a9c8177 +2 Nodes configured +0 Resources configured + Online: [ pcmk-1 pcmk-2 ] Full list of resources: ----- - -Next, check for any ERRORs during startup - there shouldn't be any. - -[source,C] ----- -# grep -i error /var/log/messages ----- - -or (on Fedora 20) - -[source,C] ----- -# journalctl | grep -i error ----- - -Repeat these checks on the other node. The results should be the same. - -endif::[] - -ifdef::crmsh[] -Now that we have confirmed that Corosync is functional we can check -the rest of the stack. Start Pacemaker and check the necessary -processes have been started. - -[source,C] ----- -# systemctl start pacemaker.service -# ps axf - PID TTY STAT TIME COMMAND - 2 ? S 0:00 [kthreadd] -...lots of processes... -28019 ? Ssl 0:03 /usr/sbin/corosync -28047 ? Ss 0:00 /usr/sbin/pacemakerd -f -28048 ? Ss 0:00 \_ /usr/libexec/pacemaker/cib -28049 ? Ss 0:00 \_ /usr/libexec/pacemaker/stonithd -28050 ? Ss 0:00 \_ /usr/lib64/heartbeat/lrmd -28051 ? Ss 0:00 \_ /usr/libexec/pacemaker/attrd -28052 ? Ss 0:00 \_ /usr/libexec/pacemaker/pengine -28053 ? Ss 0:00 \_ /usr/libexec/pacemaker/crmd ----- -If that looks ok, check the logs and crm_mon. -[source,C] ----- -# grep pacemakerd /var/log/messages | grep -e get_cluster_type -e read_config -Apr 3 09:19:32 pcmk-1 pacemakerd[28047]: info: get_cluster_type: Detected an active 'corosync' cluster -Apr 3 09:19:32 pcmk-1 pacemakerd[28047]: info: read_config: Reading configure for stack: corosync -# crm_mon -1 -============ -Last updated: Tue Apr 3 09:21:37 2012 -Last change: Tue Apr 3 09:19:54 2012 via crmd on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -1 Nodes configured, unknown expected votes -0 Resources configured. -============ +PCSD Status: + pcmk-1: Online + pcmk-2: Online -Online: [ pcmk-1 ] +Daemon Status: + corosync: active/disabled + pacemaker: active/disabled + pcsd: active/enabled ---- -Next, check for any ERRORs during startup - there shouldn't be any. - -[source,C] +Finally, ensure there are no startup errors (aside from messages relating +to not having STONITH configured, which are OK at this point): ---- -# grep -i error /var/log/messages +[root@pcmk-1 ~]# journalctl | grep -i error ---- -Repeat on the other node and display the cluster's status. - -[source,C] +[NOTE] +====== +Other operating systems will report startup errors in other locations. +For example, on Fedora 19 and earlier, the command would be: ---- -# ssh pcmk-2 -- systemctl start pacemaker.service -# crm_mon -1 -============ -Last updated: Tue Apr 3 09:26:23 2012 -Last change: Tue Apr 3 09:26:21 2012 via crmd on pcmk-1 -Stack: corosync -Current DC: pcmk-1 (1702537408) - partition with quorum -Version: 1.1.7-2.fc17-ee0730e13d124c3d58f00016c3376a1de5323cff -2 Nodes configured, unknown expected votes -0 Resources configured. -============ - -Online: [ pcmk-1 pcmk-2 ] +[root@pcmk-1 ~]# grep -i error /var/log/messages ---- +====== -endif::[] +Repeat these checks on the other node. The results should be the same. diff --git a/doc/Clusters_from_Scratch/en-US/Clusters_from_Scratch.ent b/doc/Clusters_from_Scratch/en-US/Clusters_from_Scratch.ent index ecc8c1303a..eafd2819e2 100644 --- a/doc/Clusters_from_Scratch/en-US/Clusters_from_Scratch.ent +++ b/doc/Clusters_from_Scratch/en-US/Clusters_from_Scratch.ent @@ -1,6 +1,6 @@ - + - + diff --git a/doc/Clusters_from_Scratch/en-US/Clusters_from_Scratch.xml b/doc/Clusters_from_Scratch/en-US/Clusters_from_Scratch.xml index a9b29363b5..4586c9ecd7 100644 --- a/doc/Clusters_from_Scratch/en-US/Clusters_from_Scratch.xml +++ b/doc/Clusters_from_Scratch/en-US/Clusters_from_Scratch.xml @@ -1,24 +1,24 @@ %BOOK_ENTITIES; ]> - + diff --git a/doc/Clusters_from_Scratch/en-US/Revision_History.xml b/doc/Clusters_from_Scratch/en-US/Revision_History.xml index 19dd3191f6..0df7bbc577 100644 --- a/doc/Clusters_from_Scratch/en-US/Revision_History.xml +++ b/doc/Clusters_from_Scratch/en-US/Revision_History.xml @@ -1,55 +1,62 @@ %BOOK_ENTITIES; ]> + Revision History 1-0 Mon May 17 2010 AndrewBeekhofandrew@beekhof.net Import from Pages.app 2-0 Wed Sep 22 2010 RaoulScarazzinirasca@miamammausalinux.org Italian translation 3-0 Wed Feb 9 2011 AndrewBeekhofandrew@beekhof.net Updated for Fedora 13 4-0 Wed Oct 5 2011 AndrewBeekhofandrew@beekhof.net Update the GFS2 section to use CMAN 5-0 Fri Feb 10 2012 AndrewBeekhofandrew@beekhof.net Generate docbook content from asciidoc sources 6-0 Tues July 3 2012 AndrewBeekhofandrew@beekhof.net Updated for Fedora 17 7-0 Fri Sept 14 2012 DavidVosseldvossel@redhat.com Updated for pcs + + 8-0 + Mon Jan 05 2015 + KenGaillotkgaillot@redhat.com + Updated for Fedora 21 +