The vSphere HA checklist contains requirements that you must be aware of before creating and using a vSphere HA cluster.

Review this list before you set up a vSphere HA cluster. For more information, follow the appropriate cross reference.
  • All hosts must be licensed for vSphere HA.
  • A cluster must contain at least two hosts.
  • All hosts must be configured with static IP addresses. If you are using DHCP, you must ensure that the address for each host persists across reboots.
  • All hosts must have at least one management network in common. The best practice is to have at least two management networks in common. You should use the VMkernel network with the Management traffic checkbox enabled. The networks must be accessible to each other and vCenter Server and the hosts must be accessible to each other on the management networks. SeeBest Practices for Networking.
  • To ensure that any virtual machine can run on any host in the cluster, all hosts must have access to the same virtual machine networks and datastores. Similarly, virtual machines must be located on shared, not local, storage otherwise they cannot be failed over in the case of a host failure.
    Note: vSphere HA uses datastore heartbeating to distinguish between partitioned, isolated, and failed hosts. So if some datastores are more reliable in your environment, configure vSphere HA to give preference to them.
  • For VM Monitoring to work, VMware tools must be installed. See VM and Application Monitoring.
  • vSphere HA supports both IPv4 and IPv6. See Other vSphere HA Interoperability Issues for considerations when using IPv6.
  • For VM Component Protection to work, hosts must have the All Paths Down (APD) Timeout feature enabled.
  • To use VM Component Protection, clusters must contain ESXi 6.0 hosts or later.
  • Only vSphere HA clusters that contain ESXi 6.0 or later hosts can be used to enable VMCP. Clusters that contain hosts from an earlier release cannot enable VMCP, and such hosts cannot be added to a VMCP-enabled cluster.
  • If your cluster uses Virtual Volume datastores, when vSphere HA is enabled a configuration Virtual Volume is created on each datastore by vCenter Server. In these containers, vSphere HA stores the files it uses to protect virtual machines. vSphere HA does not function correctly if you delete these containers. Only one container is created per Virtual Volume datastore.