I have an update on this post with a workaround from Microsoft PSS.
How do you migrate from a Windows Server 2008 Hyper-V cluster to Windows Server 2008 R2? The process is that you build a new cluster and migrate the VM’s over. If you have a tight budget you will be evicting a cluster node from the W2008 cluster, rebuilding it with W2008 R2 and then setting up a new cluster. OK, not perfect, but at least you get a clean new cluster.
You then migrate the VM’s over from the old cluster to the new one. Because you do not have W2008 R2 on the old cluster you cannot use Storage Quick Migration. This means shutting down each VM in a maintenance window, exporting it and importing it in the new cluster. That’s quite manual. If you have VMM 2008 R2 you could use a cold migration. Here, you shut down the VM and use VMM to migrate the files. It does all the export/import and does the file transfer using BITS.
As you clear out the VM’s from each W2008 node, you evict it from the old cluster, rebuild it with W2008 R2 and add it to the new cluster.
Problem! What if you can only free up one machine for the new W2008 R2 cluster? OK, you can build up a one node cluster. Windows Server has no issue with that. Neither does Hyper-V. Obviously you have no server fault tolerance until you add a second node. But you’ll do that once you free up a host in the old cluster.
Unfortunately though, VMM 2008 R2 does have a problem with one node clusters. I’ve set one up and this is what happens when I added the cluster to the console. The node cannot be refreshed and cannot be used by VMM:
“Warning (13926)
Host cluster <cluster FQDN> was not fully refreshed because not all of the nodes could be contacted. Highly available storage and virtual network information reported for this cluster might be inaccurate.
Recommended Action
Ensure that all the nodes are online and do not have Not Responding status in Virtual Machine Manager. Then refresh the host cluster again.”
I’m not the only person to experience this. Another virtual machine MVP has posted in Connect (I added a note) discussing the issue. It does appear to be a logic bug in VMM 2008 R2, preventing us from using VMM 2008 R2 as part of the initial migration. It looks like we’ll have to use the Hyper-V console until we can free up a second node from the old W2008 cluster and add it into the new cluster. Of course, you then face a scenario where VMM cannot manage the last remaining node in the W2008 cluster and you’ll have to use the Hyper-V console to manually move the VM’s to the W2008 R2 cluster.
Ouch. This is why MS should give me €30K worth of hardware and somewhere to host it 🙂 I found a similarly annoying logic bug in VMM 2008 which I got a fix written for (released as part of a rollup back around March/April 2009).
Unless we get a fix then this appears to be the scenario:
- You don’t have unlimited h/w budget: You will have a single node W2008 R2 cluster at the start of the migration and a single node W2008 cluster at the end of the migration. You will need to use the Hyper-V console to manually migrate VM’s while you have single node clusters.
- You have unlimited budget and can justify having 2 more host servers at the end of the project than you did at the start: Buy 2 new W2008 R2 host servers and set up your new cluster. You can use VMM 2008 R2 to cold migrate the VM’s from the W2008 cluster to the W2008 R2 cluster. At the end you will have 2 vacant W2008 cluster hosts that you will have to find a new use for.
This is a pity. I hope MS fixes it. It’s a shame to deprive people of the power of VMM and it’s PowerShell module during these critical stages of a Hyper-V W2008-W2008 R2 migration.
EDIT:
I put out a shout to my fellow MVP’s and got a response pretty quick. One of them says he’s managing a single node cluster with no issues. He accomplished this by editing the properties of the cluster in VMM and setting the “Cluster Reserve (Nodes)” to 0. The effect of this is that you tell VMM that you want zero redundant nodes in the cluster. It is set to one by default, giving you an N+1 cluster with 1 node for fault tolerance.
I did this and had no joy with the W2008 R2 cluster. I ended up migrating a node into it later today and re-adding the cluster. It’s working perfectly. The setting does appear to work for a single node W2008 cluster that we have up.