ESXi 5.1 vCenter shows all disconnected

[yarecki]

I found myself in a weird situation where I was asked to do some modifications in a VM settings on a very old ESXi infrastructure. Can't be  rocket science I thought so I agreed.
What I found myself in is that I even couldn't log on to the vSphere web client I was pointed to. I found the IP was down. After reviewing what's left in the documentation for the infra I found there were 2 vCenter Server Apliances and I managed to access the second one, then reset the SSO password and access Web Client running on that second VM. When I look in the UI though only the decommed system shows up as the vCenter server with all the physical hosts down as as it turns decommed. I can even see the VCA VM listed there as disconnected too.
Disregarding the decommed systems, I'm still seeing all that infrastructure and I can even connect to some of the VMs so they must be running under another vCenter then but I don't know how to get on that running vCenter so I can see the current working infrastructure and make the modifications I need to make. Clearly the "disconnected" VM running web client has all the data for the other branch or whatever it is so should also have the details on the existing one.

[As an update]  I found that one of the cluster member hosts is pingable and I managed to reconnect it. This reconnected all the VMs hosted on that host.

[jsm79]

Yeah, I'd start backtracking to the hosts first to ascertain what is actually on those hosts before I got too concerned with trying to track down phantom vCenter Servers.

Once you get logged in to the hosts via the host client, you can see what VCSAs might be running on them, and login to the vCenter Server Management web interface of them (just like logging in to the vSphere Client, just add the port 5480 behind the server name/IP, and use the root creds instead of SSO creds), and check their SSO status from there.