High availability means that a virtual machine will be automatically restarted if its process is interrupted. This happens if the virtual machine is terminated by methods other than powering off from within the guest or sending the shutdown command from the Manager. When these events occur, the highly available virtual machine is automatically restarted, either on its original host or another host in the cluster.

High availability is possible because the Red Hat Enterprise Virtualization Manager constantly monitors the hosts and storage, and automatically detects hardware failure. If host failure is detected, any virtual machine configured to be highly available is automatically restarted on another host in the cluster. In addition, all virtual machines are monitored, so if the virtual machine's operating system crashes, a signal is sent to automatically restart the virtual machine.

With high availability, interruption to service is minimal because virtual machines are restarted within seconds with no user intervention required. High availability keeps your resources balanced by restarting guests on a host with low current resource utilization, or based on any workload balancing or power saving policies that you configure. This ensures that there is sufficient capacity to restart virtual machines at all times.