[VMware Tips] How to unlock an ISO file mounted to a VM running vCenter

You might be wondering why the need to add a dvd drive to a VM running vCenter in the first place.

Well, I recently had to upgrade a vCenter Server Appliance (VCSA) from version 6.5 to 6.5 U1e for a customer by using the offline bundle rather than the online method. This is why I needed to add a dvd drive to the vCenter VM and then mount the VCSA update ISO file. Everything went just fine and my VCSA was up to date and running after a couple of minutes and a reboot.

The thing is that I didn’t immediately un-mount the ISO file and remove the dvd drive from the vCenter VM after the upgrade ; and a few days later I had to configure VCHA (vCenter High Availability) which allow to have a passive vCenter to go online in case of failure of the active node. I won’t go into further details as this is not the topic today.

I was almost done with the configuration of VCHA but got stuck because of the ISO file mounted to the vCenter VM, and of course I couldn’t just un-mount the ISO from the vSphere Web Client. So I tried to ssh the vCenter and unlock the ISO but apparently linux commands don’t work on Photon OS like I expected. Then I tried again multiple times to un-mount the ISO but things started to get worse as the vCenter got unresponsive for about 5 minutes and I couldn’t even ping it.

Fortunately I remembered on which ESXi host the vCenter was running and got connected to it to see what was happening. The VM was still running and I was able this time to remove the dvd drive once and for all.

I just had to answer “Yes” once I got the pop-up below and then I was good to go.

The vCenter was then back online and running like nothing happened and I was finally able to configure VCHA with a passive node waiting to go online (hopefully it’ll never have to) and a witness VM to monitor the whole thing.

Hope this will help you out if you’re facing the same issue.

See you next time!

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