A cluster is a group of independent computers that jointly run a series of applications and appear to clients and applications as a single system. The computers are physically connected and share cluster software. The computers that make up the cluster are known as nodes.
The services offered by a cluster system include high performance, high availability, load balancing and scalability. These services can be combined. What’s more, the cluster offers a large administration capacity, providing a single point of control, local or remote, to administrators.