Heartbeat is an open-source program that provides cluster infrastructure capabilities — cluster membership and messaging — to client servers. These capabilities are a critical component in a high availability (HA) server infrastructure. In this tutorial, we will demonstrate how to create a 2-node HA server setup by simply using Heartbeat and a DigitalOcean Floating IP.
Heartbeat is typically used in conjunction with a cluster resource manager (CRM), such as Pacemaker, to achieve a complete HA setup. If you are looking to create a more robust HA setup, look into using Corosync and Pacemaker or Keepalived.