We discussed virtual IP addresses earlier; now, it's time to leverage them properly. A virtual IP is not a service in the traditional sense, but it does provide functionality that we need in a highly-available configuration. In cases where we also have control over DNS resolution, we can even assign a name to the virtual IP address to insulate applications from future changes.
For now, this recipe will limit itself to outlining the steps required to add a transitory IP address to Pacemaker.
As we're continuing to configure Pacemaker, make sure you've followed all the previous recipes.
We will assume that the 192.168.56.30
IP address exists as a predefined target for our PostgreSQL cluster. Users and applications will connect to it instead of the actual addresses of pg1
or pg2
.
Perform these steps on any Pacemaker node as the root
user:
Add an IP address
primitive
to Pacemaker withcrm
:crm configure primitive pg_vip ocf:heartbeat...