vSphere HA

VMware vSphere HA protects virtual machines and vSphere hosts in a cluster by providing high availability. The vSphere HA agent monitors vSphere hosts and detects any failure occurring in the hosts. Once a vSphere host fails, vSphere HA restarts virtual machines to another available vSphere host. In a vSphere cluster, a host is elected as a master host by the vSphere HA agent and other hosts are elected as slaves. The master host monitors the slave hosts in the cluster and also monitors state of the virtual machines that are being protected by vSphere HA. The vSphere HA agent is installed on the vSphere host when it is added to a vSphere cluster.

The agent then communicates with the other vSphere agents that it finds in the cluster. A vSphere cluster can have a single vSphere host as a master, and the remaining vSphere hosts are slave hosts. If a vSphere master host fails, a reelection is held and a new master host is elected.