This is a text-only version of the following page on https://raymii.org: --- Title : Corosync Pacemaker - Execute script on failover Author : Remy van Elst Date : 20-11-2013 URL : https://raymii.org/s/tutorials/Corosync_Pacemaker_-_Execute_a_script_on_failover.html Format : Markdown/HTML --- With Corosync/Pacemaker there is no easy way to simply run a script on failover. There are good reasons for this, but sometimes you want to do something simple. This tutorial describes how to change the Dummy OCF resource to execute a script on failover.

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In this example it is a script which triggers a few SNMP traps, sends an alert to Nagios and sends some data to Graphite. SNMP alone could be done with the `ocf:heartbeat:ClusterMon` resource, but the other stuff not. This is a very very simple way of doing it, I find it more a quick hack. For example, the script path is hard coded. For me that is not a problem because both the script as the Dummy resource are managed via Ansible, so I can change them any time. Start by copying the Dummy resource over to a new resource. On Ubuntu the resource files are located here: /usr/lib/ocf/resource.d/heartbeat/ In there, copy the `Dummy` file to a new resource, for example `FailOverScript`. If you don't have the Dummy resource, you can also find it [here][2]. Edit the name and description: Name: meta_data() { cat < 1.0 Description: Script ran on Failover Script ran on Failover Make sure the script you want to execute is placed on the host, and is executable (`chmod +x /usr/local/bin/script`). A bit lower in the file, edit the `dummy_start` function. Add the script path below the `if [ $? = $OCF_SUCCESS ]; then` and above the `return $OCF_SUCCESS` lines. Like so: dummy_start() { dummy_monitor /usr/local/bin/failover.sh if [ $? = $OCF_SUCCESS ]; then return $OCF_SUCCESS fi touch ${OCF_RESKEY_state} } After that has been done, replace all instances of Dummy and dummy with your name of choice: sed -i 's/Dummy/FailOverScript' /usr/lib/ocf/resource.d/heartbeat/FailOverScript sed -i 's/dummy/failoverscript' /usr/lib/ocf/resource.d/heartbeat/FailOverScript Test the script using the `ocf-tester` program to see if you have any mistakes: ocf-tester -n resourcename /usr/lib/ocf/resource.d/heartbeat/FailOverScript Output: Beginning tests for /usr/lib/ocf/resource.d/heartbeat/FailOverScript... /usr/sbin/ocf-tester: 214: /usr/sbin/ocf-tester: xmllint: not found * rc=127: Your agent produces meta-data which does not conform to ra-api-1.dtd * Your agent does not support the notify action (optional) * Your agent does not support the demote action (optional) * Your agent does not support the promote action (optional) * Your agent does not support master/slave (optional) Tests failed: /usr/lib/ocf/resource.d/heartbeat/FailOverScript failed 1 tests Oops. Seems we need `xmllint`. On Ubuntu, install it: apt-get install libxml2-utils Test again, you'll see it will pass: Beginning tests for /usr/lib/ocf/resource.d/heartbeat/FailOverScript... * Your agent does not support the notify action (optional) * Your agent does not support the demote action (optional) * Your agent does not support the promote action (optional) * Your agent does not support master/slave (optional) /usr/lib/ocf/resource.d/heartbeat/FailOverScript passed all tests As an extra test, to see if the script you've created is correctly executed, you can do a test start of the resource: export OCF_ROOT=/usr/lib/ocf bash -x /usr/lib/ocf/resource.d/heartbeat/FailOverScript start To use this resource, add it like so: crm configure primitive script ocf:heartbeat:FailOverScript op monitor interval="30" If you want to test it, you can for example let the script send you an email. Put a node in standby and see if you get an email. [1]: https://www.digitalocean.com/?refcode=7435ae6b8212 [2]: https://github.com/ClusterLabs/resource-agents/blob/master/heartbeat/Dummy --- License: All the text on this website is free as in freedom unless stated otherwise. This means you can use it in any way you want, you can copy it, change it the way you like and republish it, as long as you release the (modified) content under the same license to give others the same freedoms you've got and place my name and a link to this site with the article as source. This site uses Google Analytics for statistics and Google Adwords for advertisements. You are tracked and Google knows everything about you. Use an adblocker like ublock-origin if you don't want it. 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