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Hyper-v Cluster low priority for some servers

    Question

  • Hi,

    I have 2 nodes cluster for my hyper-v environement. each of this nodes run multiple VMs.

    I have other servers that are not powerful enough to run as many VMs at the same time. These servers could run probably only 1 VM each.

    Is it possible to add these servers to my cluster, and assign only 1 VM to each one of these (low end) hosts. And if there is an issue and a  failover happens , I would like these VMs to go back to the big hosts, and then move them back to the low end host when the issue is resolved.

    Basically, I want to take advantage of these small servers and run 1 VM on each, but if there is a failover, I don't want the cluster to try to push more VMs to these small servers because it won't be able to handle it. (Having a way to tell the cluster what host each VM could run on)

    Thank you.


    -Mehdi

    Wednesday, March 20, 2013 5:41 PM

Answers

  • Hi,

    What's the OS version of your Hyper-V cluster node server?

    Currently, I don’t have a Hyper-V cluster at hand, I can’t check that. But from Windows Server 2008 R2 file cluster, we can modify possible owners option at: resource properties --> Advanced Policies --> Possible Owners


    Lawrence

    TechNet Community Support

    • Marked as answer by MehdiS Friday, March 22, 2013 3:10 PM
    Friday, March 22, 2013 6:40 AM
    Moderator

All replies

  • You can assign Possible Owners to any cluster resource.  So you could specify that the low powered nodes are possible owners of only a specific VM.  That would be the only VM that could run on it.  With scripting, you could adjust anything according to whatever parameters you want.

    .:|:.:|:. tim

    Wednesday, March 20, 2013 5:48 PM
  • Hi,

    Thank you for your answer.

    Are you sure about this?

    When I go to the properties of a cluster resource, I can set the preferred owners. But what I understand, is that this is used only for a fail back after a failover.

    All my resources have no preferred owners and yet they still failover between the 2 nodes.



    -Mehdi

    Wednesday, March 20, 2013 9:20 PM
  • Hi,

    There are two options in resource properties: Preferred Owners and Possible Owners.

    When you set the preferred owners for a group to a subset of the nodes in a cluster, specified nodes are set at the front of the list. While the rest of the cluster nodes will be appended to the list, and the group will still failover to every node in the cluster before going back to the first node in the preferred owners list. 

    In other words, in a 4 node cluster, when an administrator sets the preferred owners for a group to {3, 4}. Remember that the rest of the nodes are added to the end of the preferred owners list.  So internally, the preferred owners list is {3, 4, 1, 2}.  If the group is on node 4 and fails, it will move to node 1, not node 3. Ultimately, it’s about availability.  If the group fails on node 3, and then also fails on node 4, it’s probably better to try the other nodes, instead of retrying on node 3. 

    For Possible Owners, absolutely, positively not come online on a node that is not a possible owner.  If no possible owner nodes are up, then the groups will still failover to a node that’s not a possible owner, but it will not come online.

    In your scenario, you can add these low end hosts to this cluster, while do not configure them as possible owner for VM running in powerful Hyper-V server. Also for these VMs running in powerful Hyper-V server, configure Preferred Owner and Failback Policy to reduce the possible failover to low end server.

    So in case the powerful server down, VMs can failover to next powerful server and failback after failure server up. Even in case they failover to the low end host, they will not come online.

    For more information please refer to following MS articles:

    Preferred Owners in a Cluster
    http://blogs.msdn.com/b/clustering/archive/2008/10/14/9000092.aspx
    Failover behavior on clusters of three or more nodes
    http://support.microsoft.com/kb/299631
    Failover/Failback Policies on Microsoft Cluster Server
    http://support.microsoft.com/kb/197047

    Hope this helps!

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    Lawrence

    TechNet Community Support

    Thursday, March 21, 2013 5:51 AM
    Moderator
  • Thank you Lawrence for your answer.

    I just checked, when I go to the cluster interface--> Role--> Properties of a VM, I see only preferred owners.

    Where do I find Possible Owners?


    -Mehdi

    Thursday, March 21, 2013 2:31 PM
  • Hi,

    What's the OS version of your Hyper-V cluster node server?

    Currently, I don’t have a Hyper-V cluster at hand, I can’t check that. But from Windows Server 2008 R2 file cluster, we can modify possible owners option at: resource properties --> Advanced Policies --> Possible Owners


    Lawrence

    TechNet Community Support

    • Marked as answer by MehdiS Friday, March 22, 2013 3:10 PM
    Friday, March 22, 2013 6:40 AM
    Moderator
  • Thank you Lawrence.

    I am using Windows 2012. I found it.

    I think it's not obvious to find.

    When you go to your Roles, you have your VMs listed on the right. If you right click on a VM and go to Properties, you can change the preferred owners and the failover properties.

    However to change the Possible owners, you need to click on the VM, go to the bottom of the page and instead of summary tab, change to Resources tab (not very visible), then click on virtual machines there, right click and go to Properties. There you will find the Advanced Policies tab for Possible Owners.

    Thank you.


    -Mehdi

    Friday, March 22, 2013 3:14 PM