Can’t configure VMware HA – unknown error

Whilst running though the upgrade to vCenter 4.1 the installer will update the VPXA agent on each host when you reconnect it within the vSphere client. Great! Unless that is, you start getting HA errors….

If you had HA running before, you can pretty much guarantee that the settings are correct, DNS/Host files are all set correctly and there shouldn’t be any IP connectivity issues… well, sometimes the agent upgrade doesn’t quite work correctly, and removing the host from the cluster means moving all your VM’s to other hosts, placing it in maintenance mode, and then finally removing the host from vCenter. If you’ve got Virtual Distributed Switches, this becomes much more of a pain too! Well, you could just temporarily stop host monitoring from HA in the HA settings on the cluster and then perform the following to remove the vCenter and HA agents from the affected host:

From a CLI (SSH session):

  1. Login to your host and sudo up to root level access.
  2. Type the following and press enter:rpm -qa | grep -i aam
  3. This should give two lines for an answer, both need removing using the following (altering <version number> with your version listed from the above command):rpm -e VMware-aam-vcint-<version number>
    rpm -e VMware-aam-haa-<version number>
  4. You then need to run this command:rpm -qa | grep -i vpxa
  5. And then remove that package with this command (altering <version number> with your version listed from the above command):rpm -e VMware-vpxa-<version number>
  6. Wait a few minutes and vCenter should show that host as “Disconnected”.
  7. Right click on the host, and click Connect. Follow the wizard and the agents should be re-installed.
  8. Re-enable host monitoring from within the cluster settings, and HA should be configured on the affected host.

Hope that helps others out there…!


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