How do I configure a stonith device using agent fence_vmware_rest in a RHEL 7 or 8 High Availability cluster with pacemaker?

Solution Verified - Updated -

Environment

  • Red Hat Enterprise Linux (RHEL) 7 Update 5
  • Red Hat Enterprise Linux (RHEL) 8
  • Pacemaker High Availability or Resilient Storage Add On
  • VMware vSphere version 6.5 and above.

Resolution

  • Assuming following is cluster architecture:

    • cluster node hostnames are node1 and node2
    • cluster node names as seen by the vmware hypervisor (ESXi/vCenter) are node1-vm and node2-vm
    • <ESXi/vCenter IP address> is IP address of vmware hypervisor which is managing cluster nodes VMs
  • First check if cluster node is able to reach the hypervisor and list VMs on it. Following command will try to connect to hypervisor with provided credentials and list all machines.

     # fence_vmware_rest -a <ESXi/vCenter IP address> -l <esxi_username> -p <esxi_password> --ssl-insecure -z -o list | egrep "(node1-vm|node2-vm)"
     node1-vm,
     node2-vm,
     # fence_vmware_rest -a <ESXi/vCenter IP address> -l <esxi_username> -p <esxi_password> --ssl-insecure -z -o status -n node1-vm
     Status: ON
    
  • If above list fails, then make sure the below is true

  • If command succeeded the node is able to communicate with hypervisor. Stonith device should be configured using same configuration options as were tested in listing. Some of arguments for the fence_vmware_rest command and fence_vmware_rest fencing agent in pacemaker can have slightly different name.
    For this reason check the help pages of both - fence_vmware_rest command and fence_vmware_rest fencing agent (In diagnostics section is shortened listing of options used by this solution)

  • Create the stonith device using command below. The pcmk_host_map attribute is used to map node hostname as see by cluster to the name of virtual machine as seen on vmware hypervisor.

  • The first attribute in pcmk_host_map is the cluster node name as seen in /etc/corosync/corosync.conf file and the next attribute, that is post semicolon is the cluster node names as seen by the vmware hypervisor.

    # cat /etc/corosync/corosync.conf
    [...]
    nodelist {
        node {
            ring0_addr: node1  <<<=== Cluster node name
            nodeid: 1
        }
    
        node {
            ring0_addr: node2
            nodeid: 2
        }
    }
    
    # pcs stonith create vmfence fence_vmware_rest pcmk_host_map="node1:node1-vm;node2:node2-vm" ipaddr=<ESXi/vCenter IP address> ssl=1 login=<esxi_username> passwd=<esxi_password> ssl_insecure=1
    
  • To check the status of stonith device and its configuration use the commands below.

    # pcs stonith show
    Full list of resources:
    vmfence (stonith:fence_vmware_rest):    Started node1
    
    # pcs stonith show vmfence --full
     Resource: vmfence (class=stonith type=fence_vmware_rest)
      Attributes: pcmk_host_map=node1:node1-vm;node2:node2-vm ipaddr=<ESXi/vCenter IP address> ssl=1 login=<esxi_username> passwd=<esxi_password> ssl_insecure=1
    
  • When stonith device is started proceed with proper testing of fencing in the cluster.

Additional notes and recommendations:

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