The Vitual SAN host cannot be moved to the destination cluster: destination cluster vim.ClusterComputeResource:domain-### is Virtual SAN disabled

So today while I was teaching class, a student created an interesting problem.  We were doing a lab on DRS where they create a single Host Cluster for DRS and all add their hosts.

Well, one student created his own cluster, apparently checked the box for VSAN cluster in the process, added his host to it, then realized he was supposed to be in the "shared" DRS Host Cluster.

He deleted the cluster he had created, re-added his host to vCenter and when he tried to move his host into the DRS Cluster, he got the following error:

It turns out there was a VSAN datastore created with no disks in it and, his host still had an affiliation with the VSAN Cluster that no longer existed.

To resolve the problem we did the following:

Verification:

1. From Storage inventory view in vCenter, verify a VSAN datastore still exists.
2. If it does, Putty into the ESXi host or access it via its ESXi Shell & execute the command:
   esxcli vsan cluster get
3. If results appear, proceed to the solution ...

Solution:

1. From previous command line (SSH or ESXi Shell) to the affected host, execute the following command:
   esxcli vsan cluster leave
2. Now add the host to the existing Host Cluster...

Both Verification and Solution steps together look like this:

How to disable DRS for a single host in the cluster

I saw a question today which was interesting, how do I disable DRS for a single host in the cluster? I thought about it, and you cannot do this within the UI, at least… there is no “disable DRS” option on a host level. You can enable/disable it on a cluster level but that is it. But there are of course ways to ensure a host is not considered by DRS:

1. Place the host in maintenance mode
   This will result in the host not being used by DRS. However it also means the host won’t be used by HA and you cannot run any workloads on it.
2. Create “VM/Host” affinity rules and exclude the host that needs to be DRS disabled. That way all current workloads will not run, or be considered to run, on that particular host. If you create “must” rules this is guaranteed, if you create “should” rules then at least HA can still use the host for restarts but unless there is severe memory pressure or you hit 100 CPU utilization it will not be used by DRS either.
3. Disable the vMotion VMkernel interface
   This will result in not being able to vMotion any VMs to the host (and not from the host either). However, HA will still consider it for restarts and you can run workloads on the host, and the host will be considered for “initial placement” during a power-on of a VM.

I will file a feature request for a “disable drs” on a particular host option in the UI, I guess it could be useful for some in certain scenarios.

Original post by Duncan Epping from yellow-bricks.com
http://www.yellow-bricks.com/2017/01/17/disable-drs-single-host-cluster/