Ensure that your setup meets the following requirements:
The NameNode must run inside a virtual machine which is hosted on the vSphere HA cluster.
The vSphere HA cluster must include a minimum of two ESXi server machines. See the NameNode hardware recommendations available here.
The vSphere HA cluster must use shared storage.
Note Shared storage stores the state of the NameNode edit journal and checkpointed image. It provides ability to start the NameNode on another physical machine in the vSphere HA Cluster. Additionally, vSphere uses the shared state for the NameNode’s root VM disk.