I faced this issue with my vCenter servers (VCSA 6.5), when I disconnect (un-mount) a CD/DVD ISO image from the VCSA virtual machine, the vCenter server itself gets disconnected for few minutes then come back online and the CD/DVD ISO image remains mounted. In this article I will explain why this happens and give you a simple work around to fix this.

This issue happens only with LINUX VMs, and never happen with Windows VMs as Windows OS has no issues when the CD/DVD virtual drive is disconnected, but it;s a bit different in Linux OS, in Linux you need first to unmount the CD Rom drive from the OS first, and then disconnect the ISO image from the VM configuration, if you attempt to remove/disconnect the ISO image (from the VM configuration settings) without first un-mounting the CD -ROM drive from within the guest OS, a question will come up in the VM summary page in the vsphere web client informing you that the removal operation of the CD -ROM drive will disrupt the VM temporally, and asks you if you want to proceed or not, before you make a selection the VM is disconnected by the way as if the guest OS is suspended, and the VM is not accessible, and then the VM will come back again to live when you make a selection, and the same happens for the vCenter VCSA virtual machine, and why would you need to mount a CD to a VCSA anyway? most probably for installing patches, so when you finish using the CD and attempt to remove it from the VCSA VM, you should be answering the question at the VM summary page to proceed with the removal (detaching) of the CD, but you wont be able to either see the question nor answer it since vSphere web client goes offline, and there’s no command for the VCSA Linux Photon OS to unmount the CD (if I am not mistaken), I’ve asked VMware support team about a command for that purpose but they couldn’t help as there’s no command ….

VMware has stated that this issue is supposed to be fixed in vCenter 6.5 update 1-d according to the RELEASE NOTES, but it seems that the bug wasn’t fixed. I hope they fix this in a future release.

Finally, here’s a simple work around to fix this:

• Locate the host that your VCSA runs on, and then connect directly to that host.
• select and edit the VCSA VM configuration settings.
• detach the ISO image by deselecting the “connected” option for the virtual CD drive.
• save the settings.
• the question will pop-up as shown below, select “YES” and then click “OK”.

NOTE: perform this only from the ESXi client, not from both sides from the vCenter web client and the host client as this may corrupt the VMX file of the VCSA VM, I suffered from this issue as well.

I hope this has been informative.

Cheers :),