Installing the necessary components
The two main components of the software we use in this chapter are Corosync and Pacemaker. Each of these comprises, or depends on, several other elements and prerequisites. For now, we'll simply refer to the entire suite as Pacemaker, as it comprises the bulk of how we will control the failover system.
This recipe should be relatively short, as we will only discuss the installation of Corosync and Pacemaker, not their configuration.
Getting ready
Red-Hat-based systems such as Fedora, CentOS, and Scientific Linux will already have Pacemaker in their repositories. Debian and its derivatives such as Ubuntu also include Pacemaker as an optional install from standard repositories. Red Hat Enterprise Linux (RHEL) itself, however, only offers the software as a paid add-on, available at this URL:
https://www.redhat.com/apps/store/add-ons/
Whatever choice you make, it shouldn't be necessary to compile Pacemaker from source on most Linux distributions.
