Remove Host from vCenter while keeping VM's online?

[mac1978]

Planning on moving serveral esx hosts to a new vcenter server.  The hosts are connected to the current vcenter server and are in a cluster.  I would like to keep all VM's running while doing so.

If I try to remove the hosts I receive the message to put the host into maintenance mode first.  All guides I have read state the same: "put the hosts into maintenance mode first and then remove from vcenter".  In testing I have found that I can disconnect a host first, and then remove.  However, when adding the host to a new vcenter server it prompts that the server is already managed by another server, which then requires the manual removal of agents and some further steps.

Is there a method to "cleanly" remove an esx host from one vcenter without going into maintenance mode while keeping all VM's on the host running?

[markdjones82]

Mac,

  You can do this by Disconnecting the host first, then removing from inventory.  I have done this many times, but there is one caveat.  If you are on a VDS you will want to move it to a standard switch with all the guests as well before removing.

When you connect it to the new Vcenter it will update the vcenter agent without any issues.

[mac1978]

Not using a VDS.  The disconnect and remove method seems like the way to go.  However, why would this not be the documented method?  Why does vmware suggest putting in maintenance mode to remove instead of disconnect?

[markdjones82]

I suppose because from a supportability method that is the cleanest way to do it without possible impact to guests, but I've done this many times and haven't ran into any issues.