Virtual Machines Running or Registered on Multiple ESX Servers

Click Of Death In VcenterDoes your vCenter¬†flicker when browsing clusters? There could be a problem…

Over the last¬†3 years¬†I’ve seen this happen twice and both times it was not good.

Both cases were caused by an HA event that was interrupted, which left multiple VMs registered on more than one host. Fortunately, the VM stays running and the fix does not cause an outage but it is intimidating having to “KILL” VM processes.

HA being HA might have caused it and the KB below gives more causes and the solution.

HA is a good thing to have enabled, but if your NOC is monitoring your VMs and they see an alert that VMs are powering off they will log into the VIC and start powering them back on, no downtime right? That’s one of the main causes of this problem and VMware admins need to educate their NOC admins on letting HA do its job power VMs back on.

Now, the devil’s advocate in me says that sounds good but how does a NOC know it’s a VM or a bunch of VMs? And, don’t we tell them to just treat them like any other server? The devil’s advocate has a good question and I will ask for help answering it. Can I get feedback on how to avoid this issue when an event happens that might cause “VM jumpers”?

Here’s a must-know process for every VMware Admin on how to fix this problem…

VMware KB Link: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1005051

Here’s how VMware describes it:

  • After one of the following, a Virtual Machine appears as being registered on two ESX Servers:
    • A VMotion fails to complete correctly or times out in VirtualCenter
    • A DRS issue where virtual machines are VMotioned automatically in quick succession
    • When a machine is powered on during VMware HA failover.
    • The Service Console on an ESX host is low on memory starving the vpxa process
  • In VirtualCenter, you see the virtual machine as appearing on one ESX Server for a few seconds, then it seems to be on the other.
    The virtual machine may appear to jump back and forth among different ESX hosts.
To correct this misconfiguration:
  1. Click Inventory in the navigation bar. Expand the inventory as needed and click the appropriate managed host.
  2. Click the Virtual Machines tab.
  3. Note the virtual machine that disappears every few seconds.
  4. Log in as root with SSH to both affected ESX hosts.
  5. Run the vmware-cmd -l command to display the names of the virtual machines registered on this host.
    Run the vm-support -x command to show which virtual machines are currently running on the ESX host.

    Compare results from these commands to determine which ESX host has the virtual machine registered, but is not running it. When you have determined this, you need to unregister the virtual machine from the ESX host on which it is registered but not running.

  6. Run the following command to unregister the virtual machine from the ESX host:
    vmware-cmd -s unregister .vmx
  7. If the virtual machine has a process (PID) associated with it, ESX may not allow you to unregister it and the command fails with the error:

    If you see this error and are unable to unregister the virtual machine:
    • Kill the process for the virtual machine in the Service Console with the following two commands:
      • ps -auwwwxx | grep -i
      • kill -9 <PID of the process returned from the above command>
    • Unregister the virtual machine from the ESX host again with the command:
      vmware-cmd -s unregister .vmx
    • Run the following command to stop the hostd process:¬†
      service mgmt-vmware stop
    • Use a text editor to open the¬†/etc/vmware/hostd/vmInventory.xml file.
    • Locate the machine you want to remove.
    • Remove all of the information between the <ConfigEntry> tags for the affected virtual machine.
    • Run the following command to start the hostd process:

      service mgmt-vmware start

    VMControl error -999: Unknown error: SoapError: ServerFaultCode(0): (The attempted operation cannot be performed in the current state (Powered On).)
  8. Log in to all of your ESX Server Hardware directly using VI Client.

    You see the virtual machine on both ESX hosts with a Powered-on status. One host however does not display any details of VMware Tools, IP address, etc in the Summary tab.

  9. Click the virtual machine on the host that does not display any details in the Summary tab.
  10. Right-click the virtual machine, and click Power Off.
Note: VMware recommends restarting the mgmt-vmware and vmware-vpxa processes on any hosts on which you have changed registered machines from the command line. For more information, see Restarting the Management agents on an ESX Server (1003490).

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