vCenter Appliance 6.5 - no network

[7007VM7007]

I had to restore the vCenter Appliance 6.5 in my environment but after it restored successfully and booted up just fine I had no networking so I couldn't ping the IP/hostname or browse to the web client.

When I tried to make hardware changes to the VM I get this error:

I'm using distributed switches for everything and have no standard switches.

After plenty of Googling a few web sites said I should change the MAC address in:

/etc/udev/rules.d/ 70-persistent-net.rules

The problem is I don't have this file to edit as it isn't present in this directory.

How can I get the networking working again in the vCenter Appliance? I've tried restoring a couple of times, even to a different host but it hasn't helped.

[daphnissov]

If you only have vDS and your vCenter that manages that is down you'll need to create a temporary vSS with a port group to which you can attach the vCSA. Once it's back up, you need to configure the port group on the vDS for Ephemeral mode so this doesn't happen again. You should be able to use the vCSA console to configure the IP information if it is truly lost.

[7007VM7007]

I created a temporary vSS and have now changed the vCSA to use this new port group on the temporary vSS.

The problem I have now is that I don't have any free physical NICs to assign to this temporary vSS and if I try to edit one of the vDS switches that have two NICs in a team it is greyed out.

Can I take a physical NIC from the vDS so I can temporarily assign it to the new vSS I created so I can access the web client again?

[daphnissov]

If your vCenter that manages the vDS is down, you can't reassign an uplink to a vSS. You may need to run a temporary cable and assign that as an uplink on a single host to make the change.

[7007VM7007]

Sorry I don't quite follow. Run a temporary cable from where to where to make the change?

[daphnissov]

I was trying to say you may need to temporarily cable another NIC on an ESXi host in order to assign that as an uplink to a new vSS.

[7007VM7007]

I was afraid you were going to say that as I have no free NICs in the host (they are all assigned to the vDS).

Do I have any other options?

[daphnissov]

You can evacuate a host and reset the networking on it, then assign uplinks. I haven't tried this in a long time, so I don't know how vCenter 6.5 will cope when it returns to service and must rectify a host that it now sees as "broken", but that's the only other way I know of.

[7007VM7007]

Thanks for the help!

I have found a spare NIC so I am going to try using this NIC as an uplink with the temporary vSS to see if this will help me get access to the vCSA again.

[7007VM7007]

I forgot to ask, what do I do to prevent this from happening again in the future with vCSA?

[daphnissov · Accepted solution]

Create a new distributed port group on your vDS and set the binding mode to ephemeral. Set the VLAN ID to whatever network your vCenter requires (if applicable). This will serve as a "rescue" port group in the case where vCenter goes down again or must be restored. Port groups with ephemeral bindings do not rely upon vCenter to work. See Chris Wahl's article here for more information and a +1.

[7007VM7007]

Thank you!

I'm going to try installing the spare NIC tomorrow in the same VLAN as the vCSA on the temp vSS and then see if I can fix this mess!

[7007VM7007]

Installed spare NIC. Couldn't assign the spare NIC to the new vSS in the HTML5 interface but it worked from the cli. I was then able to change the vCSA to use the port group on the vSS and this restored connectivity to the vCSA!

I have created a new portgroup on the vDS with "Ephemeral - no binding" and put it in the same VLAN as my vCSA uses so if this issue occurs again hopefully I can just assign the vCSA temporarily to the "rescue" port group (as I have called it) and then be able to boot up the vCSA.

Thanks for the help, you helped me save my vCSA and I learned something new!

[daphnissov]

Glad to hear. You probably want to update your HTML5 host client with the present version on the fling site. It may fix that issue for you.