Changing the IP address of a vCenter 7.0 U3 appliance

[pasalott]

We are currently running vSphere 7 Update 3. We will be integrating our production VMware environment with Cisco ACI (software defined networking) and we will be moving from a class B (172.x.x.x) to a Class A (10.x.x.x.) network for our vCenter server, ESXi hosts and VMs.

My questions involves what impact changing the IP of our production vCenter appliance (which is in linked mode with our vCenter at our backup data center) will have.

This VMware KB article ( https://kb.vmware.com/s/article/1001493 ) indicates that ESXi hosts will disconnect from vCenter after changing the vCenter IP address, since the ESXi hosts use the vCenter IP and not the hostname for heartbeats.  Has this been the experience of anyone here who may have changed the IP address of a vCenter 7 appliance?  i did change the IP address of a vCenter 6.7 appliance back in 2020 and did not experience hosts disconnecting.

The kb article mentions different options to re-connect the hosts, which also states that those options may not work, which is disconcerting.  Simply reconnecting the disconnected hosts will not work apparently, so the kb article lists steps to edit to config store on each ESXi hosts, which seems to be time consuming.  The article also mentions that editing the config store may not work, in which case, removing the hosts from inventory and adding back should resolve.

The problem is that we use distributed switches for our guest vlans / port groups.  We cannot remove a host from inventory without guests losing network connectivity.

It would seem we would then have to change the IP of the vCenter server back to the original IP, then plan a huge migration of all of our production VMs, over 500, to standard switches, change the vCenter IP to the new IP, then remove and add all ESXi hosts back to inventory, then migrate all VMs back to distributed switches.  I'm hoping this is not the case. 

For vCenter 6.7, I simply changed the vCenter IP and all was fine.  I was always under the impression that changing the FQDN of a vCenter appliance was problematic, but not the IP, since everything should be pointing to the FQDN of the vCenter server (except maybe some third party components).  I'm not sure if something changed in vSphere 7 to where this is no longer the case.

[Kinnison]

Hi,

Honestly, that article has me a bit perplexed. Since your IT context is of a certain complexity and size, I, personally (Obviously), think it would be good to involve support and ask for more clarification on this.

Regards,
Ferdinando

[pasalott]

I already did.  VMware support pretty much blew me off and said that Production support is for break / fix only and then pointed me to another article about how to change the vCenter IP without addressing my concerns related to the KB article regarding ESXi hosts disconnecting.

[Kinnison]

Hi,

I didn't understand, really they "dismissed" you by telling if "for a series of unfortunate events" things don't work they intervene otherwise it should be enough to read some KB articles, At this point, perhaps it might be worth taking the time to build a sort of "homelab", at least you can get an idea of ​​what you might be facing.

Regard,
Ferdinando

[pasalott]

I just wanted to follow up to see if anyone else here has had experience in changing the vCenter appliance IP for vCenter 7?

We do have a smaller VDI VMware environment, that isn't considered as critical, where I will be making the IP change for that vCenter server first.  We will probably be changing the IPs in the next two weeks.  I was just hoping to get more insight into this before then.

[Murthuja_Vali]

Hello, 

Did you face host disconnection after IP change?

If yes, have you figured it out the best way to change the vCenter IP without impacting host disconnections.

[pasalott]

Luckily, not really.  The only issue we had was with the few of our ESXi hosts in the DMZ.  They intermittently disconnected from vCenter after the upgrade.  Once I just chose to reconnect the hosts and then restart them, they stopped disconnecting.  All of our other ESXi hosts in our internal network had no issues.