EVC on a cluster

[johncol]

Hi there

I was wondering if there is anyway I can add a host with running vm's into a EVC cluster, is there any cheat around the restrictions in the kb below. what if I created a new non EVC cluster, added the hosts then enabled EVC? I wont be able to reboot machines immediatley to take advantage of the new EVC mode.

Cannot add an ESX/ESXi host with running virtual machines to an EVC enabled Cluster (1009571)

Resolution

An EVC enabled Cluster cannot determine the CPU Compatibility features used by any of the running virtual machines. A host has to be put in maintenance mode before it can be added to the EVC cluster.

To place the ESX host into maintenance mode:

1. vMotion the running virtual machines from the standalone host to the hosts already in the cluster.
2. When all of the machines are finished migrating, place the ESX host into maintenance mode.
3. Add the host to the cluster.

OR

1. Power down all of the running virtual machines on the ESX host.
2. Place the host into maintenance mode.
3. Add the host to the cluster.

If vCenter Server is a virtual machine:

1. Power down virtual machines on host B.
2. Add host B to EVC Cluster.
3. Perform one of these options:
   • Power down the vCenter Server virtual machine on host A.
     
     Or
     
     
   • Unregister the vCenter Serever virtual machine using the vSphere Client connection directly to host A.
     
     
4. Connect to host B via vSphere Client, register the vCenter virtual machine and power on.
5. Power down all remaining virtual machines on host A and add to EVC Cluster

[rpotru]

Never tried disabling EVC and adding host to the cluster. It is not advisable though. You will see problems later.

Best practice is to follow the KB article you mentioned.

[Asifsshaikh]

or you can disable DRS if enabled or EVC for time being and then try... though i never tried these...

Let's share the results.

Regards,

Asif.

[Sreejesh_D]

there is no supported way to doi this from VMware.

1. We cant add a host with running VMs to an EVC enabled cluster .

2. we cant enable EVC on a cluster which has running VMs.

[Sreejesh_D]

Try this out. I havnt tried. May be worth to give a try.

Q: Is there a way to enable EVC without shutting down all your VMs?

A: Yes, there is, but deppending on the size of your environment it might or might not be right for you. First VMotion all VMs of a host in the cluster. Then moving the host into a newly created cluster. Enable EVC on this cluster and then VMotioned VMs from the old cluster to the new cluster, emptying yet another host which could then be moved to the new cluster. In this way, you can enable EVC without bringing VMs down.

Remark: Be sure to start with the “oldest” host, because this will make your baseline. At this time (nov-2008), there isn’t much difference in cpu families that will cause different baselines, but in the feature there will be.

There is a drawback to this method however, permissions for groups and DRS /HA rules you’ve created at the cluster level, are lost and there is no way to export and import them to the new cluster. You have to re-enter these rules by hand. So, depending on the number of rules you have created, this method might work for you.

http://www.gabesvirtualworld.com/the-real-questions-about-evc/