Renumbering a VEM on the Cisco 1000V

For a while, I’ve been looking for a way to pick which “slots” our VEM’s go into on the 1000V VSM.  It would make troubleshooting much easier, and it just makes more sense to the networking guys who are used to working with physical line cards and supervisors.

A network escalation engineer over at VMware came through with a process for renumbering the VEM’s.  It’s simple, but it never really occurred to me that it was this simple.

All you need to do is grab the host id of the VMware host from the VSM config, shut down the host to take the VEM offline, and then renumber it in the VSM config.

Here’s a screenshot @benperove sent over detailing the process.  I’m definitely doing this ASAP on my 1000V’s!  Thanks Ben!


5 comments Add yours
  1. I’m curious to know what this does to your Eth interface numbering and any port-channels those interfaces are in. Assuming your interface numbering changes because of the new VEM number, do existing port-channels with those interfaces simply get updated, or does it create new ones? 

    1. Andy:  I tried it this AM.  If you have channel-group auto mode on, it will create a new port-channel with the new Eth ports.  Otherwise, you will have to manually create, or edit the port-channel.  

      1. I figured as much. I do like “preregistering” the VEMs. We’ve been doing this for while as it helps to ensure the server & network teams both stay in the loop on new host deployments. I’ve actually asked the 1000v PM team for a feature that wouldn’t allow a host to join if its UUID wasn’t already preregistered.

        1. Good idea.  I would like a vCenter option when you add a host to the 1000V, so you can assign an available VEM number.  😉  

          Also, one other thing I would find VERY helpful is a link between a 1000V “copy run start” and vCenter.  Had an issue where we were trying something with a new ethernet port profile, and didn’t copy run start it.  VSM went down when we tried a failover, and when it came back up, vCenter had an orphaned port group that the 1000V didn’t have.  After 4 hours on the phone, had to clear out the entire vCenter database to fix that.  NOT cool.  

  2. You don’t have to shut down the host. You can just stop/start the VEM process (vem stop, vem start) from the ESXi CLI. Also handy to keep an eye on “show module vem missing” to confirm the vem is offline before you start.

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