Enable VM High Availability
PMO supports virtual machine high availability using OpenStack availability zones. Refer here for more information on the VM HA architecture in PMO
Pre-requisites for enabling VM High Availability
1. You must be an administrator to enable VM high availability.
2. To enable high availability, you must first create an availability zone for a given host aggregate and then enable this availability zone.
3. There need to be a minimum of 4 hypervisors in an availability zone to enable this feature for it.
4. Evacuation on host failure requires that all the hypervisors use shared storage for instance data or all instances are booted from volumes.
5. When authorizing the hypervisors, you need to specify a Cluster IP address for each node that is reachable by all other nodes in the zone. Please ensure this IP address is not accessible over the public Internet.
Create Availability Zone
It is assumed that you are logged in to the Platform9 Clarity UI as an administrator.
To create an availability zone, follow the steps given below.
1. Click Infrastructure in the left panel.
2. Click the Host Aggregates tab.
3. Click Add a New Host Aggregate.
4. Enter the aggregate name in Name.
5. Select the Create new availability zone.
6. Enter the name of the new availability zone in Availability Zone Name.
7. Select the check boxes for the hosts to be included in the host aggregate from the list of hosts.
8. Click Create Host Aggregates.
Enable High Availability
Once an availability zone has been created, you can enable VM high availability for all instances running within the selected availability zone.
When high availability is enabled by Platform9 support, the host agent installs Consul on the hosts.
To enable high availability, follow the steps given below.
1. Click Infrastructure in the left panel.
2. Click the Host Aggregates tab.
3. Click the Availability Zones tab.
4. Select an availability zone from the list of availability zones.
5. Click Enable.
High availability is now enabled on the selected availability zone. Applications requiring high availability should be deployed into the availability zone.
Once high availability is enabled on the availability zone, you may view the status of the HA cluster under the High Availability column.
View Consul Information
Consul is a service that provides the health status of each host in the availability zone. The Consul agent runs in a client or server mode on each host. When a new host is added to the availability zone, it is automatically registered on the Consul cluster. For more information on Consul, refer to the Consul website.
To view consul information about hosts in the high availability zone, click the Availability Zone link in the list of availability zones seen under Infrastructure>Host Aggregates>Availability Zones tab.
