Cluster

How To Setup High Availability Cluster on CentOS 8 / RHEL 8

High Availability cluster , also known as failover cluster or active-passive cluster, is one of the most widely used cluster types in a production environment to have continuous availability of services even one of the cluster nodes fails.

In technical, if the server running application has failed for some reason (ex: hardware failure), cluster software (pacemaker) will restart the application on the working node.

Failover is not just restarting an application; it is a series of operations associated with it, like mounting filesystems, configuring networks, and starting dependent applications.

Environment

Here, we will configure a failover cluster with Pacemaker to make the Apache (web) server as a highly available application.

Here, we will configure the Apache web server, filesystem, and networks as resources for our cluster.

For a filesystem resource, we would be using shared storage coming from iSCSI storage.