Configuring vSphere HA on a cluster fails due to "Host Status is unknown" in vLCM

Products

• VMware vSphere ESXi

Issue/Introduction

• vSphere HA cannot be enabled on an ESXi host in an single image-based cluster.
  
  
• On vCenter > ESXi Host Cluster  > Updates tab we see Host status has following error
  
  

• Host status is unknown. 
  The host could not be reached, and its image compliance could not be checked. Try refreshing image compliance again - the host may be reached successfully.
  During remediation, this host may get remediated if it can be reached successfully.

• From the /var/log/vmware/vmware-updatemgr/vum-server/vmware-vum-server.log in vCenter server observed the following events.

YYYY-MM-DDTHH:MM:SST warning vmware-vum-server[#####] [Originator@6876 sub=com.vmware.vcIntegrity.lifecycle.DesiredScanClusterTask opID=29####13c-####-####-####-5408#####86aa] [Task, ######] Task:com.vmware.vcIntegrity.lifecycle.DesiredScanClusterTask ID:52###ab0-####-####-####-1790####bcf3. Status is still pending for host : <ESXI-FQDN> (host-####) ..Waiting.
...
YYYY-MM-DDTHH:MM:SST info vmware-vum-server[#####] [Originator@6876 sub=StageClusterTask opID=29####13c-####-####-####-5408#####86aa] [Task, ######] Task:com.vmware.vcIntegrity.lifecycle.StageClusterTask ID:528###05-####-####-####-7#######1c0. Skipping unavailable host ID: host-####, Name: <ESXI-FQDN>

 

Environment

VMware vCenter Server

Cause

Inbound connection on port 9084 towards the vCenter server from the ESXi host was not allowed:

• nc -vz <VC-FQDN> 9084

nc: connect to VC-FQDN port 9084 (tcp) failed: Connection timed out

Resolution

1. Allow port 9084 between vCenter server and ESXi hosts. Reference Port and Protocols

2. Perform the Compliance check on vSphere Cluster (Navigate to the cluster, then select the Updates tab)

3. Re-enable the  vSphere HA on the cluster, see Disabling and enabling VMware High Availability (HA)

4. Validate vSphere HA configuration on the ESXi host (Host -> Summary tab -> Configuration -> vSphere HA state)