After upgrading your Virtual Center (vCenter) Server you may find that one or more of your ESX hosts in an HA cluster display the error message:

“An error occurred during configuration of the HA Agent on the host”.

When you look further into the ‘Task Details’ (assuming that you’ve already tried to ‘Reconfigure for VMware HA’ or similar in trying to resolve the issue) you may see the error:

“cmd addnode failed for primary node: /opt/vmware/aam/bin/ft_startup failed”

This is a known issue with VMware Virtual Center 2.5 Update 3 – see the U3 release notes here for confirmation. 

To resolve this error remove the HA from the cluster and then re-apply HA to it again.  When all ESX hosts in the cluster have had HA re-enabled you should see that the HA error previously seen has now gone.

This issue is still present with the recent Virtual Center 2.5 U4 release so you may still see it even after updating to this latest release.

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