XenServer: Missing network interface – pool member

I have encountered several times that after a shutdown and restart on a XenServer host when it is configured as a pool, sometimes the pool members come up with no management interface because there are no network cards shown. The main reason I have seen this is because the pool-master server changes its IP address – this could be something as simple as changing the IP address, a DHCP address change, or a change of the PIF (physical interface) used for management. In these cases, if the pool slave cannot find the master, it will go into emergency mode to protect the VMs. However, the problem this presents is that there are no network cards available on the slave, no management interface, and the VM’s which were running on that server (even if you’re using shared storage) are unavailable.

The resolution is very quick and simple…

First, verify that you are in emergency mode by running the following from the command line interface on the pool slave host “xe host-is-in-emergency-mode” – – if it returns TRUE then read on, if it returns FALSE then this will not resolve your problem.

Next, verify what the IP address is of your running POOL MASTER (this assumes your POOL MASTER is still running, otherwise you will need to perform an emergency transition)….

On the pool slave, run the following “xe pool-emergency-reset-master master-address=xxx.xxx.xxx.xxx” — where xxx.xxx.xxx.xxx is the IP address of your working pool master…

Upon success it will notify you it will make the change within 10 seconds….

After 10 seconds, run “xe host-is-in-emergency-mode” — if it returns false you should be all set. You may need to refresh (disconnect/reconnect) to the pool in XenCenter.

If your pool-master is unavailable, or all of your hosts are showing no network adapter, then you will need to transfer the master role to one of the servers, from the command line, run: “xe pool-emergency-transition-to-master”

That will make this host the new pool master. Return to the menu system “xsconsole” and document that IP address as the pool master, and then continue the documentation above.