When all you virtual machine networks are on the vDS.
We are migrating all our Virtual machines to ESXi 4.1 clusters. Several machines were already running on the new clusters, so we felt it was time to move our vCenter server to it’s new location. Luckily we decided to test this first in our test environment.
The new clusters are all configured with Virtual Connect and all the virtual machine networks are defined on network adapters that are connected to a vDS. In our test environment we have the vCenter server on one virtual machine and the database (SQL server) on another virtual machine. We powered them both down and imported them with converter standalone. Then we powered them on again and thought this would be it. Obviously, this was not the case.
First of all, they were both powered on, on a different ESXi server and with no networking present, they could not see eachother. Wich meant, no vCenter server and no option to add the servers VMXnet3 adapters to the vDS, since you cannot edit a vDS when there is no vCenter present. I powered them down again and added them both to the inventory of 1 ESXi server. Created a standard vSwitch and added them both to this vSwitch. Now they could see eachother and the vCenter server service started, but, off course, there was no network to the oudside world and all ESXes and vm’s were unreachable. Now I had the vCenter running, but I was still not able to edit the vDS.
I could, however, edit the vDS physical network adapters. So I pulled a physical network adapter from the vDS and attached it to the standard vSwitch, I had created on the ESXi host.
Promptly our vCenter had a connection to the outside world again. All machines were connected and I was able to edit the vDS to add the vCenter server and SQL server. I added the physical network adapter back to the vDS and cleaned up the standard vSwitch I made.
When it was time to move the production vCenter server, we encountered no problems and it worked fine using this method. The other solution would be, to make sure, when possible, to run your vCenter server virtual machine for one environment on a different vCenter server. When you have to move one server, your networking of the VM would still be available, since it is managed by the other vCenter server. In our case we have 2 vCenters in production, in linked mode, and one for testing purposes only. We could indeed do this, but then, I wouldn’t have had this much fun.