need down time re-connecting hosts to a new vCenter Server?

[saymOU]

I recently upgraded VirtualCenter Server 2.0 to vCenter Server on a different server. My original VirtualCenter was using MSDE, and had connectivity problems when moving it to a remote SQL 2005 server, so I decided to backup the db, copy it to a SQL 2005, then install VirtualCenter Server 2.0 on a new server with the intention of upgrading to vCenter Server from there. The upgrade was successful, and I am able to connect to the db using a domain service account. I am able to connect to the license server which I also moved from the old to the new server. The hosts and all the VMs show up in the inventory, but they are disconnected.

If I attempt to reconnect the host, will it cause down time on the VMs? I know it will prompt me for a username and pwd for the hosts, but it'll also tell me that another server is managing the hosts, so if I continue with the connection wizard, will it stop the agent service? If the vpxa version isn't correct, will the service stop running when attempting to re-connect the hosts?

Since the vpxa version is 2.0, will I need to re-install the agent now that I have vCenter Server running? I've read that if I remove the hosts, delete the vpxuser account from them, then re-add the hosts, it will re-install the agent and re-create vpxuser. Won't this cause the VMs to shutdown?

My main concern is downtime. How can I transition to the new vCenter Server without affecting VMs?

I would appreciate some expert advise or input from someone who has done this. Thanks.

[Troy_Clavell]

you should be fine and the VM's will continue to run. If the management agents need to be upgraded they will during the "add host" portion.

Until the agents are updated the host and it's guests will appear as disconnected by the VM's will continue to run.

[saymOU]

Thanks for the quick response. Do I need to remove the hosts from the old VirtualCenter first, or can I add the hosts in the new vCenter Server and acknowledge that I want to contine even though another server is already managing them? I've read two different answers to this, so clarification is appreciated.

[rob_nixon]

I'm about to do this same thing. My concern is bringing across all the folders with their permissions, resource groups, etc. If I just add the host servers to a new vCenter server, the VMs will get dumped into one folder. Can anyone explain how this should work.

Rob

[saymOU]

I ended up following instructions from http://communities.vmware.com/message/914798#914798, but when adding one of the hosts back into the new vCenter server, the vpxa service stalled and couldn't communicate to the host. I had to ssh into the host and restart the vmware-vpxa service. Once it restarted, I was able to add the host.

Initially, I had the hosts already added, but they were showing as disconnected. All of the VMs at that point were in the correct folders; however, once I removed the hosts and re-added them, they did not go back into their correct folders. Some of my permissions also disappeared, while most of them stayed in tact. This could be because I still have ESX 3.0.

I've read that rather than removing the hosts from the new vCenter server, you can click connect on each disconnected host, enter the root username and password, and continue after it warns you that another server is managing this host. This is suppose to allow you to connect the hosts while keeping all of the permissions and VMs in the correct folders; however, I think you'll still need re-add them in the resource pool. I tried this as well, and again the agent stalled. I think it's a bug in ESX 3.0, but I'm planning to upgrade to vSphere soon.