High-availability clusters, also referred to a as HA clusters or failover clusters, are collection of computers that provision server applications that can be unfailingly operated with a least possibility of downtime. They function by leveraging the benefits of redundant computers in assemblages or clusters that provide unrelenting service in the cases when the system components fail to work unexpectedly. Without assembling, in case a server running a specific application crashes, the application will be inaccessible till the worn-out server’s issue is not resolved.
HA clustering remedies this status quo by identifying the hardware or software erroneousness, and promptly restarting the application on another system without the need for executive interference, a procedure known as failover. As a part of this procedure, clustering software may configure the node before starting the application on it. For instance, applicable file systems may require importing and mounting, network hardware may have to be arranged, and some supportive applications may need to be working as well.