1.4. Installing Red Hat High Availability Add-On software

To install Red Hat High Availability Add-On software, you must have entitlements for the software. If you are using the Conga configuration GUI, you can let it install the cluster software. If you are using other tools to configure the cluster, secure and install the software as you would with Red Hat Enterprise Linux software.

Upgrading Red Hat High Availability Add-On Software

It is possible to upgrade the cluster software on a given major release of Red Hat Enterprise Linux without taking the cluster out of production. Doing so requires disabling the cluster software on one host at a time, upgrading the software, and restarting the cluster software on that host.

Shut down all cluster services on a single cluster node. For instructions on stopping cluster software on a node, refer to Section 8.1.2, “Stopping Cluster Software”. It may be desirable to manually relocate cluster-managed services and virtual machines off of the host prior to stopping rgmanager.
Execute the yum update command to install the new RPMs. For example:
```
# yum update -y openais cman rgmanager lvm2-cluster gfs2-utils
```
Reboot the cluster node or restart the cluster services manually. For instructions on starting cluster software on a node, refer to Section 8.1.1, “Starting Cluster Software”.