One method of providing vCenter Server availability is to use the Watchdog feature in a vSphere HA cluster. Watchdog monitors and protects vCenter Server services. If any services fail, Watchdog attempts to restart them. If it cannot restart the service because of a host failure, vSphere HA restarts the virtual machine running the service on a new host. Watchdog can provide better availability by using vCenter Server processes (PID Watchdog) or the vCenter Server API (API Watchdog).