ESX hosts show as disconnected after VirtualCenter upgrade

Products

• VMware vSphere ESXi

Issue/Introduction

Symptoms:

• After upgrading VirtualCenter to 2.5 the ESX hosts are showing as disconnected
• Trying to reconnect the ESX hosts results in an error message:
  
  Host is not communicating or the Host agent is not running
  
  
• Investigation of the ESX host shows the correct vpxa agent is running.

Resolution

Note: Before you begin, see Restarting the Management agents on an ESX Server (1003490) for important information on restarting the mgmt-vmware service.

In some cases upgrading VirtualCenter does not successfully install the newly required management agents on the ESX hosts.

To resolve this problem apply one of the following workarounds:

1. Restart the management agents on each ESX host. For more information, see Restarting the Management agents on an ESX Server (1003490).
   
2. Manually create the missing directory on each ESX host by running the following command.
   
   [root@esxhost]# mkdir -p /tmp/vmware-root

Reconnect the ESX hosts. You are prompted for root credentials and the updated VirtualCenter agent is successfully installed.