Chapter 3. Installing and configuring Instance HA

Red Hat OpenStack Platform (RHOSP) director deploys Instance High Availability (HA). However, you must perform additional steps to configure a new Instance HA deployment on a new overcloud. After you complete the steps, Instance HA will run on a subset of Compute nodes with a custom role.

Important

To enable instance HA in a different environment, such as an existing overcloud that uses standard or custom roles, perform only the procedures that are relevant to your deployment and adapt your templates accordingly.

For general information about deploying the overcloud, see Director Installation and Usage guide. For more information on custom roles, see Composable Services and Custom Roles in the Advanced Overcloud Customization guide.

3.1. Configuring the Instance HA role, flavor, and profile

Procedure

You can modify the example file and role names in the following procedure according to your environment.

  1. Add the ComputeInstanceHA role to your roles-data.yaml file and regenerate the file.

    $ openstack overcloud roles generate -o ~/my_roles_data.yaml Controller Compute ComputeInstanceHA

    The ComputeInstanceHA role includes all the services in the default Compute role, the ComputeInstanceHA services, and the PacemakerRemote services. For general information about custom roles and about the roles-data.yaml file, see Roles in the Advanced Overcloud Customization guide.

  2. Create the compute-instance-ha flavor to tag the Compute nodes to manage with Instance HA.

    $ source ~/stackrc
    $ openstack flavor create --id auto --ram 6144 --disk 40 --vcpus 4 compute-instance-ha
    $ openstack flavor set --property "cpu_arch"="x86_64" --property "capabilities:boot_option"="local" --property "capabilities:profile"="compute-instance-ha" compute-instance-ha
    $ openstack flavor set --property resources:VCPU=0 --property resources:MEMORY_MB=0 --property resources:DISK_GB=0 --property resources:CUSTOM_BAREMETAL=1 compute-instance-ha
  3. Tag each Compute node that you want to manage with Instance HA with the compute-instance-ha profile, and replace <NODE UUID> with the actual UUID:

    $ openstack baremetal node set --property capabilities='profile:compute-instance-ha,boot_option:local' <NODE UUID>
  4. Map the ComputeInstanceHA role to the compute-instance-ha flavor by creating an environment file with the following parameter:

    parameter_defaults:
      OvercloudComputeInstanceHAFlavor: compute-instance-ha

3.2. Enabling fencing

Enable fencing on all Controller and Compute nodes in the overcloud by creating an environment file with fencing information.

Procedure

  1. Create the environment file in an accessible location, such as ~/templates, and include the following content:

    parameter_defaults:
      EnableFencing: true
      FencingConfig:
        devices:
        - agent: fence_ipmilan
          host_mac: 00:ec:ad:cb:3c:c7
          params:
            login: admin
            ipaddr: 192.168.24.1
            ipport: 6230
            passwd: password
            lanplus: 1
        - agent: fence_ipmilan
          host_mac: 00:ec:ad:cb:3c:cb
          params:
            login: admin
            ipaddr: 192.168.24.1
            ipport: 6231
            passwd: password
            lanplus: 1
        - agent: fence_ipmilan
          host_mac: 00:ec:ad:cb:3c:cf
          params:
            login: admin
            ipaddr: 192.168.24.1
            ipport: 6232
            passwd: password
            lanplus: 1
        - agent: fence_ipmilan
          host_mac: 00:ec:ad:cb:3c:d3
          params:
            login: admin
            ipaddr: 192.168.24.1
            ipport: 6233
            passwd: password
            lanplus: 1
        - agent: fence_ipmilan
          host_mac: 00:ec:ad:cb:3c:d7
          params:
            login: admin
            ipaddr: 192.168.24.1
            ipport: 6234
            passwd: password
            lanplus: 1

    For more information about fencing and STONITH configuration, see Fencing Controller Nodes with STONITH in the High Availability Deployment and Usage guide.

  2. Instance HA uses shared storage by default. If shared storage is not configured for your Compute instance, add the following parameter to the environment file that you created:

    parameter_defaults:
      ExtraConfig:
        tripleo::instanceha::no_shared_storage: true

    For information about how to boot from an OpenStack Block Storage (cinder) volume instead of configuring shared storage for the disk image of an instance, see Chapter 2, Planning your Instance HA deployment.

3.3. Deploying the overcloud

You can configure Instance HA for your overcloud at any time after you create the undercloud. If you already deployed the overcloud, you must rerun the openstack overcloud deploy command with the additional Instance HA files you created.

Procedure

  • Use the openstack overcloud deploy command with the -e option for each environment file that you created and with the compute-instanceha.yaml environment file. Replace <FLAVOR_ENV_FILE> and <FENCING_ENV_FILE> with the appropriate file names in your environment:

    $ openstack overcloud deploy --templates \
      -e <FLAVOR_ENV_FILE> \
      -e <FENCING_ENV_FILE> \
      -e /usr/share/openstack-tripleo-heat-templates/environments/compute-instanceha.yaml
    Note
    • Do not modify the compute-instanceha.yaml environment file.
    • Include the full path to each environment file that you want to include in the overcloud deployment.

Result

After the deployment is complete, each Compute node includes a STONITH device and a GuestNode service.

3.4. Testing Instance HA evacuation

Warning

The following procedure involves deliberately crashing a Compute node, which triggers the automated evacuation of instances with Instance HA.

Procedure

  1. Start one or more instances on the overcloud.

    stack@director $ . overcloudrc
    stack@director $ openstack server create --image cirros --flavor 2 test-failover
    stack@director $ openstack server list -c Name -c Status
  2. Log in to the Compute node that hosts the instances and change to the root user. Replace compute-n with the name of the Compute node:

    stack@director $ . stackrc
    stack@director $ ssh -l heat-admin compute-n
    heat-admin@compute-n $ su -
  3. Crash the Compute node.

    root@compute-n $ echo c > /proc/sysrq-trigger
  4. Wait a few minutes for the node to restart, and then verify that the instances from the Compute node that you crash are re-created on another Compute node:

    stack@director $ openstack server list -c Name -c Status
    stack@director $ openstack compute service list