How to correct 'Unable to contact the specified host' from VirtualCenter

Issue:

You receive the following error message when VirtualCenter (VC) attempts to communicate with an ESX or ESXi server.

 

Unable to contact the specified host

 

Cause:

The VirtualCenter agent (vpxa) needs to be restarted.

 

Solution:

ESX

Login as root to the server console

Restart the VC agent (vmware-vpxa) using the following command

 

service vmware-vpxa restart

 

If the problem still persists remove and reinstall the VC agent on the ESX host.

1)      Remove the ESX Host from VC

a.       In the VI Client right click the ESX host and select Remove

b.      This should remove the agent, if not you can remove it manually.

2)      Manually remove the VC Agent from the ESX host using the following commands on the ESX console.

a.       Find current VC Agent version

rpm –qa |grep vpxa

 

                                                               i.      If nothing is returned the agent was removed successfully.

b.      Stop the Host Agent (mgmt-vmware)

service mgmt-vmware stop

 

c.       Stop the VC Agent

service vmware-vpxa stop

OR

/etc/init.d/vmware-vpxa stop

 

d.      Uninstall the VC agent by version returned earlier

rpm –e VMware-vpxa-2.5.0-104215

                                                               i.      Expect the following:

warning: /etc/vmware/vpxa.cfg saved as /etc/vmware/vpxa.cfg.rpmsave

 

e.       Verify the VC agent has uninstalled

rpm –qa |grep vpxa

 

3)      Add the ESX host back into the VirtualCenter Server.

 

ESXi

Select Restart Management Agents from the Customize System menu