Chapter 6. Configuring fencing for an HA cluster on Red Hat OpenStack Platform

1. Determine the UUID for each node in your cluster.

   The following command displays the full list of all of the RHOSP instance names within the ha-example project along with the UUID for the cluster node associated with that RHOSP instance, under the heading ID. The node host name might not match the RHOSP instance name.

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   # openstack --os-cloud="ha-example" server list
   …
   | ID                                  | Name             |...
   | 6d86fa7d-b31f-4f8a-895e-b3558df9decb|testnode-node03-vm|...
   | 43ed5fe8-6cc7-4af0-8acd-a4fea293bc62|testnode-node02-vm|...
   | 4df08e9d-2fa6-4c04-9e66-36a6f002250e|testnode-node01-vm|...

2. Create the fencing device, using the pcmk_host_map parameter to map each node in the cluster to the UUID for that node. Each of the following example fence device creation commands uses a different authentication method.

   1. The following command creates a fence_openstack fencing device for a 3-node cluster, using a clouds.yaml configuration file for authentication. For the cloud= parameter, specify the name of the cloud in your clouds.yaml` file.

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      # pcs stonith create fenceopenstack fence_openstack pcmk_host_map="node01:4df08e9d-2fa6-4c04-9e66-36a6f002250e;node02:43ed5fe8-6cc7-4af0-8acd-a4fea293bc62;node03:6d86fa7d-b31f-4f8a-895e-b3558df9decb" power_timeout="240" pcmk_reboot_timeout="480" pcmk_reboot_retries="4" cloud="ha-example"

   2. The following command creates a fence_openstack fencing device, using an OpenRC environment script for authentication.

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      # pcs stonith create fenceopenstack fence_openstack pcmk_host_map="node01:4df08e9d-2fa6-4c04-9e66-36a6f002250e;node02:43ed5fe8-6cc7-4af0-8acd-a4fea293bc62;node03:6d86fa7d-b31f-4f8a-895e-b3558df9decb" power_timeout="240" pcmk_reboot_timeout="480" pcmk_reboot_retries="4" openrc="/root/openrc"

   3. The following command creates a fence_openstack fencing device, using a user name and password for authentication. The authentication parameters, including username, password, project_name, and auth_url, are provided by the RHOSP administrator.

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      # pcs stonith create fenceopenstack fence_openstack pcmk_host_map="node01:4df08e9d-2fa6-4c04-9e66-36a6f002250e;node02:43ed5fe8-6cc7-4af0-8acd-a4fea293bc62;node03:6d86fa7d-b31f-4f8a-895e-b3558df9decb" power_timeout="240" pcmk_reboot_timeout="480" pcmk_reboot_retries="4" username="XXX" password="XXX" project_name="rhelha" auth_url="XXX" user_domain_name="Default"

3. To ensure immediate and complete fencing, disable ACPI Soft-Off on all cluster nodes. For information about disabling ACPI Soft-Off, see Configuring ACPI For use with integrated fence devices.

Verification

1. From one node in the cluster, fence a different node in the cluster and check the cluster status. If the fenced node is offline, the fencing operation was successful.

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   [root@node01 ~] # pcs stonith fence node02
   [root@node01 ~] # pcs status

2. Restart the node that you fenced and check the status to verify that the node started.

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   [root@node01 ~] # pcs cluster start node02
   [root@node01 ~] # pcs status