A cluster is a named collection of server instances sharing the same set of applications, resources, and configuration information. A server instance can belong to exactly one cluster. A cluster facilitates server instance load-balancing through distribution of a load across multiple machines. A cluster facilitates high availability through instance-level failover. From an administrative perspective, a cluster represents a virtualized entity in which operations on a cluster (e.g. deployment of an application) act on all instances that make up the cluster.