An administrator has implemented a hypervisor cluster with high availability enabled. They are expecting that if any of the physical servers fail, the virtual servers will be transparently migrated…

An administrator has implemented a hypervisor cluster with high availability enabled. They are expecting that if any of the physical servers fail, the virtual servers will be transparently migrated to other hypervisors in the cluster. When the first hypervisor failure occurs, all of the hosted virtual servers appear offline to users as they are moved to another host. What feature should the administrator have implemented to achieve his goal?