Question around status of VM's if a Host is removed from Cluster

Posted on 2011-04-20
Last Modified: 2012-05-11
Hi Folks,

I have a question around what happens to VM Servers running on a host when the host itself gets removed from a vCenter Cluster.  I currently have 3 hosts in a cluster in which vMotion is broken due to EVC (Hosts are different Generation HP Proliant Servers) being turned off.  I plan to both Upgrade the RAM among all the Servers currently attached to the Cluster and then migrate the VM's from the current ESXi host to a newer Host which I would like to add to the Cluster.  

Without getting too detailed with the plan, I can say that at some point I would like to Remove one of the older Hosts from the Cluster but I'm basing this on the assumption that while the Host is removed from the cluster and unlicensed, it will continue to run the VM's although I won't have the ability to use any vCenter features like cloning, templates, etc which would not be necessary.  Once I am done doing what Maintenance work I need to do I would reattach the Server to the Cluster.  The idea here is no downtime.  Could someone tell me if this is feasible?

Thanks in advance!  
Question by:RyanMyers83
    LVL 40

    Accepted Solution

    Removing a host from a cluster does not power down the VMs. They will continue to run. You can manage the host with vSphere Client by logging directly into it. If there is a possibility of you doing mgmt to the host (hardware change, etc.), I would migrate the VMs off, if you have the resources on the other hosts to do so.

    LVL 116

    Assisted Solution

    by:Andrew Hancock (VMware vExpert / EE MVE)
    VMs will function as normal only HA and DRS functions will stop working because those functions operation on the cluster.

    All other functions, Cloning, Templates will function as normal, we often move ESX hosts out of the Cluster.
    LVL 116

    Expert Comment

    by:Andrew Hancock (VMware vExpert / EE MVE)
    Licensing is assigned to the Host ESX Server.
    LVL 116

    Expert Comment

    by:Andrew Hancock (VMware vExpert / EE MVE)
    You will still have manual vMotion available to you.
    LVL 40

    Expert Comment

    "hanccocka", vMotion is always a manual process, unless you're referring to DRS?

    Yes, removing a host from a cluster doesn't remove any of the other vCenter features such as cloning, creating templates, etc. It just negates Cluster features as mentioned above.


    Author Closing Comment

    Thanks Guys.  I thought so, but I wanted to bounce it off the community.  For some reason I couldn't find anything online with a clear answer.  

    I would vMotion the VM's off the Host if I could, but alas EVC was not setup for the cluster when it was created.  I will have to play musical chairs with the Hosts to get my plan to work, but overall I should be able to move forward now that I know the VM's won't power down on me when I remove the Host from the cluster.

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