Chapter 2. Installing and configuring Instance HA You use Red Hat OpenStack Platform (RHOSP) director to deploy 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 Instance HA is not supported on RHOSP hyperconverged infrastructures (HCI) environments. To use Instance HA in your RHOSP HCI environment, you must designate a subset of the Compute nodes with the ComputeInstanceHA role to use the Instance HA. Red Hat Ceph Storage services must not be hosted on the Compute nodes that host Instance HA. 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. 2.1. Configuring the Instance HA role and profile Before you deploy Instance HA, add the Instance HA role to your roles-data.yaml file, tag each Compute node that you want to manage with Instance HA with the Instance HA profile, and add these to your overcloud-baremetal-deploy.yaml file or equivalent. For more information about designating overcloud nodes for specific roles, see: Designating overcloud nodes for roles by matching profiles . As an example, you can use the computeiha profile to configure the node. Procedure Add the role to your overcloud-baremetal-deploy.yaml file, if not already defined. Edit overcloud-baremetal-deploy.yaml to define the profile that you want to assign to the nodes for the role: Provision the overcloud nodes: Replace <stack> with the name of the stack for which you provisioned the bare-metal nodes. The default value is overcloud . Replace <deployment_file> with a name that you choose for the generated heat environment file to include with the deployment command, for example /home/stack/templates/overcloud-baremetal-deployed.yaml . 2.2. Enabling fencing on an overcloud with Instance HA Enable fencing on all Controller and Compute nodes in the overcloud by creating an environment file with fencing information. Procedure Create the environment file in an accessible location, such as ~/templates , and include the following content: If you use shared storage for your Compute instance, set the following parameter in your environment file to false : Additional resources Section 1.2, "Planning your Instance HA deployment" Fencing Controller Nodes with STONITH 2.3. Deploying the overcloud with Instance HA If you already deployed the overcloud, you can run the openstack overcloud deploy command again with the additional Instance HA files you created. You can configure Instance HA for your overcloud at any time after you create the undercloud. Prerequisites You configured a Instance HA role and profile. You enabled fencing on the overcloud. Procedure Use the openstack overcloud deploy command with the -e option to include the compute-instanceha.yaml environment file and to include additional environment files. Replace <fencing_environment_file> with the appropriate file names for your environment: 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. After deployment, each Compute node includes a STONITH device and a pacemaker_remote service. 2.4. Testing Instance HA evacuation To test that Instance HA evacuates instances correctly, you trigger evacuation on a Compute node and check that the Instance HA agents successfully evacuate and re-create the instance on a different Compute node. Warning The following procedure involves deliberately crashing a Compute node, which triggers the automated evacuation of instances with Instance HA. Prerequisites Instance HA is deployed on the Compute node. Procedure Start one or more instances on the overcloud. 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: Crash the Compute node. 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: 2.5. Designating instances to evacuate with Instance HA By default, Instance HA evacuates all instances from a failed node. You can configure Instance HA to only evacuate instances with specific images or flavors. Prerequisites Instance HA is deployed on the overcloud. Procedure Log in to the undercloud as the stack user. Source the overcloudrc file: Use one of the following options: Tag an image: Replace <image_id> with the ID of the image that you want to evacuate. Tag a flavor: Replace <flavor_id> with the ID of the flavor that you want to evacuate. If you are using host aggregates, then add the same tag or property to the host aggregates. For more information, see Flavor metadata in Configuring the Compute service for instance creation. 2.6. Additional resources Installing and managing Red Hat OpenStack Platform with director Composable services and custom roles

Commands:
- name: ComputeInstanceHA count: 2 hostname_format: compute-%index% defaults: network_config: template: /home/stack/composable_roles/network/nic-configs/compute.j2 networks: - network: ctlplane vif: true - network: internal_api - network: tenant - network: storage instances: - hostname: overcloud-novacompute-0 name: node04 - hostname: overcloud-novacompute-1 name: node05
(undercloud)USD openstack overcloud node provision --stack <stack> --output <deployment_file> /home/stack/templates/overcloud-baremetal-deploy.yaml
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
parameter_defaults: ExtraConfig: tripleo::instanceha::no_shared_storage: false
openstack overcloud deploy --templates -e <fencing_environment_file> -r my_roles_data.yaml -e /usr/share/openstack-tripleo-heat-templates/environments/compute-instanceha.yaml
stack@director USD . overcloudrc stack@director USD openstack server create --image cirros --flavor 2 test-failover stack@director USD openstack server list -c Name -c Status
stack@director USD . stackrc stack@director USD ssh -l tripleo-admin compute-n tripleo-admin@ compute-n USD su -
root@ compute-n USD echo c > /proc/sysrq-trigger
stack@director USD openstack server list -c Name -c Status stack@director USD openstack compute service list
source ~/overcloudrc
(overcloud) USD openstack image set --tag evacuable <image_id>
(overcloud) USD openstack flavor set --property evacuable=true <flavor_id>