To ensure a successful upgrade of vCenter Server in a high availability (HA) environment, your environment must meet certain prerequisites before running the upgrade.
Ensure that your environment meets the prerequisites for upgrading vCenter Server appliance. See Prerequisites for Upgrading the vCenter Server Appliance.
High Availability Prerequisites
In addition to the prerequisites for upgrading a standard vCenter Server appliance, the vCenter High Availability (vCenter HA) upgrade has the following prerequisites.
- A vCenter HA cluster consists of three vCenter Server appliances that act as Active, Passive, and Witness nodes. The Active node must be configured as the vCenter HA node.
- The Active node is part of the vCenter HA cluster.
- All nodes must be present in the cluster.
- The vCenter HA cluster must be in a healthy state.
- The vCenter HA cluster must be in enabled mode.
- The host that has the vCenter Server virtual machine (VM) must be managed by a container vCenter Server. It must not be standalone.
- The target vCenter Server must have the same placement as the source vCenter Server.
- vCenter HA cannot be set up on a vCenter Server that has disks on more than one datastore.
To learn more about vCenter HA configuration, see vSphere Availability.