High Availability Clustering

Now that we have a clear understanding of high availability, let’s talk a bit about the high-availability cluster.

A high availability cluster, also known as the fail-over cluster, contains a set of nodes running in conjunction with each other that ensures the high availability of the service.

The nodes in the cluster are connected by a private network called the heartbeat network that continuously monitors the health and the status of each node in the cluster.

A single state across all the nodes in a cluster is achieved with the help of a shared distributed memory and a distributed coordination service like the Zookeeper.

To ensure availability, HA clusters use several techniques such as disk mirroring/Redundant Array of Independent Disks (RAID), redundant network connections, redundant electrical power, etc. All the possible components having a single point of failure are made redundant to ensure the availability of the service.

Multiple HA clusters run together in one geographical zone ensuring minimum downtime and continual service. If you wish to delve more into clustering please go through my cloud course.

Alright, Folks! So now we have a pretty good understanding of scalability and high availability. These two concepts are crucial to software system design.

Let’s move on to the next chapter, where we discuss load balancing in web applications.