Where can I find resources to help me create a custom resource agent scripts for Red Hat High Availability clusters?

Environment

• Red Hat Enterprise Linux (RHEL) including:
  • Red Hat Enterprise Linux Server 5 and 6 with the High Availability Add on or Resilient Storage Add on
  • Red Hat Enterprise Linux Server 6, 7,8, 9 with the High Availability Add on or Resilient Storage Add on with Pacemaker

• Resources managed by either:
  • rgmanager ( or clurgmgrd)
  • pacemaker

Issue

• Where can I find resources to help me write custom resource agent scripts for Red Hat Cluster Suite clusters?
• Need assistance for creating a custom script resource agent to be used rgmanager or pacemaker.

Resolution

• Open Cluster Framework (OCF) definitions, specifications and documentation are available here:
  • Content from github.com is not included.The OCF Resource Agent Developer’s Guide
• Note there are 2 variations from the OCF standard used by rgmanager (or clurgmgrd):
  • rgmanager does not call monitor; it only calls status.
  • rgmanager looks for resource agents in /usr/share/cluster.

Red Hat Enterprise Linux 8

• The issue (bugzilla bug: 2103370) has been resolved with the errata RHBA-2022:7443 with the following package(s): resource-agents-4.9.0-29.el8, resource-agents-paf-4.9.0-29.el8, resource-agents-aliyun-4.9.0-29.el8, resource-agents-gcp-4.9.0-29.el8 or later.

Red Hat Enterprise Linux 9

• The issue (bugzilla bug: 2103374) has been resolved with the errata RHBA-2022:7932 with the following package(s): resource-agents-paf-4.10.0-23.el9, resource-agents-4.10.0-23.el9, resource-agents-cloud-4.10.0-23.el9 or later.

With the following errata a new tool called ocf-tester is included with the resource-agents package. This tool allows you to test if a custom or 3rd party resource-agent is OCF compliant.

Testing a resource-agent that passes the testing:

# ocf-tester -n apachetest /usr/lib/ocf/resource.d/heartbeat/apache
Beginning tests for /usr/lib/ocf/resource.d/heartbeat/apache...
* 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 promotable clones (optional)
* Your agent does not support the reload action (optional)
/usr/lib/ocf/resource.d/heartbeat/apache passed all tests

Testing a resource-agent that fails the testings because it is missing configuration files.

# ocf-tester -n testname -o httpd=/usr/sbin/nginx /usr/lib/ocf/resource.d/heartbeat/nginx 
Beginning tests for /usr/lib/ocf/resource.d/heartbeat/nginx...
* rc=2: Validation failed.  Did you supply enough options with -o ?
ls: cannot access '/etc/nginx/conf.d/*.conf': No such file or directory
ls: cannot access '/etc/nginx/default.d/*.conf': No such file or directory
ls: cannot access '/etc/nginx/conf.d/*.conf': No such file or directory
ls: cannot access '/etc/nginx/default.d/*.conf': No such file or directory
ERROR: Invalid STATUSURL http://localhost:80
Aborting tests

Root Cause

• Open Cluster Framework is a standard that extends Content from clusterlabs.org is not included.LSB Resource Agents.
• Custom resource agents should be OCF-compliant to ensure they are compatible with rgmanager or pacemaker.

Diagnostic Steps

This solution may apply to you if you need to create a custom resource agent for a service that will be managed by rgmanager or pacemaker.

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