Changing host management from one VSphere to another

[Revcall]

Hi all,

I have recently installed a second VSphere server (5.0) to replace our old one (3.5).

Is it best to migrate the VMs off of the host, detach it from the old VCenter server and then attach it to the new server?

Can I leave the VMs on the host and still move to the new VCenter server?

I plan on installing ESXi 5 on the hosts once I get them managed by VSphere 5.0.

Your help is much appreciated.

[nielse]

vCenter 5 can work with 3.5 hosts, you can add these hosts and then move your VM's to 5.0 hosts and slowly upgrade all 3.5 hosts to 5.0.

[Revcall]

So I need to move the VMs off the host before I move the hosts to the new VSphere?

Promises to be interesting as I am also switching datastores.

[TBKing · Accepted solution]

I'm going through the same fun!

First - Make sure you have your licensing all squared away.  Not sure where you are coming from, but I had to install FlexLM on my vCenter5 server and register the vi3 license files and make sure vC5 saw and read them correctly.

We're also changing the management network, so I created a 2nd console.

If the hosts are in a cluster, you have to turn off HA/DRS, evacuate the host, put in Maintenance Mode, pull the host out of the cluster, Exit Maintenance Mode, push guests back to the non-clustered host, repeat, until the cluster is empty.

Once all the hosts are non-clustered, you can Delete the host from vCenter3, and add the host to vCenter 5, while the guests are still running.

Then reverse the steps to build your HA cluster in vCenter5.

Then you can round-robin upgrade (fresh install) the hosts to vSphere 5.

Enjoy the ride!  😉

[Revcall]

Thanks TBKing!  That's what I was looking for.

I had spoken to VMWare support on a couple of occasions and I got two separate answers so I wasn't sure.  Your answer seems very reasonable.

[dcsteam]

You can actually just disconnect the host from the old vCenter with VMs running, then remove the host from the old vCenter (still with VMs running), then add the host to the new vCenter (still with VMs running).  I've not tried this method, but I see no reason why it shouldn't work.  I've had to do the same within a vCenter before so that I could add hosts in by DNS name instead of IP.  The other method is safer (using Maintenance Mode).

[TBKing]

Just did it a few minutes ago 

Yes, you can Disconnect from one, and go to the other and Add.

Previously, I was trying to Remove - which threw the Maintenance Mode alert.

.... one other "interesting" thing I found:

My two consoles are on two different interfaces, two differnet subnets, two different gateways .... BUT

If I change the default gateway for one console (vswif1) it changes the gw for the other console (vswif0)

I'm not sure how I managed to roll from one vCenter to the other without losing contact.... I first verified the destination vC could ping the new console before I disconnected... but it worked   (whew!)