How to set stonith-enabled to true in a Pacemaker cluster

Environment

• Red Hat Enterprise Linux 6 (with the High Availability or Resilient Storage Add on)
• Red Hat Enterprise Linux 7 (with the High Availability or Resilient Storage Add on)
• Red Hat Enterprise Linux 8 (with the High Availability or Resilient Storage Add on)
• Red Hat Enterprise Linux 9 (with the High Availability or Resilient Storage Add on)
• pacemaker

Issue

• How to set stonith-enabled to true in a Pacemaker cluster
• stonith-enabled is set to false in the cluster configuration
• What is the impact of stonith-enabled cluster setting?

Resolution

• Set stonith-enabled to true.

  # pcs property set stonith-enabled=true
  

Root Cause

• In order for clustered environments to receive support for cluster type issues, the value for stonith-enabled must be set to true in order for fencing to be functional. This is a support requirement, as failing to have a working fencing configuration will result in unexpected behaviors in the cluster.

  • Important Note: This is especially important to maintain stonith-enabled=true in two node clusters, as these represent a special case where split-brains are guaranteed with stonith disabled. This is due to the special two_node option which guarantees we maintain quorum ( and thus split-brain ) in a network split scenario.
    • Split-Brain occurs on two-node pacmeaker cluster while stonith is disabled and token loss occurs

• When setting stonith-enabled to true, one must also configure stonith devices. This is required for stonith to function in a predictable fashion. Setting stonith-enabled to true and not having stonith devices configured would not allow resources to start/recover correctly after a cluster node is rebooted.

• Additional resources on fencing can be found below:

  • Importance of Fencing in a Red Hat High Availability Cluster
  • Available Fencing Types and Fencing Agents for a Red Hat High-Availability Cluster
  • How to configure fence_ipmilan in a Red Hat High Availability Cluster
  • How to test fence devices in a Red Hat High Availability Cluster
  • How to troubleshoot fence_ipmilan issues

• For Openstack based environments refer to Openstack Director Installation and Usage guides under the "Fencing the Controller Nodes" section.

Diagnostic Steps

• Check the output of pcs cluster cib to check the status of the stonith bootstrap options. If no output is returned, stonith-enabled is set to true by default, event when not specifically listed in the cib:

  <nvpair id="cib-bootstrap-options-stonith-enabled" name="stonith-enabled" value="false"/>
  

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