We are running an environment with a single vCenter and 15 ESX hosts, of which 12 are in a DRS/HA cluster. When we had to do some maintenance on some of the hosts in the cluster, I moved a server into maintenance mode. Since we have DRS, the system attempted to automatically move all of the guest systems to other servers in the cluster. After 15 minutes or so, I saw an error stating that the host could not go into maintenance mode and there were two guest systems still running there.
This happens frequently because we mount ISO images and DVD-ROM drives to some of the guests when we are installing software. So, the simple answer is to edit the virtual machine settings for that guest.
On the Hardware tab
- click on the “CD/DVD Drive 1”
- select “Client Device”
- unselect “Connected”
- unselect “Connect at power on”
- click on OK.
But in 4.1 this cannot be done. Once the attempt to enter maintenance mode has failed, you will see that the “Edit virtual machine settings” is no longer available on any of the guests that caused the failure. Now what? First thing I tried was to shutdown the virtual machines. But, I could still not edit the settings. After some thought, I decided that the error was probably in vCenter and not ESX. So, I decided to remove the guest from inventory.
- right-click on the virtual machine
- select “Remove from Inventory”
- when prompted, click on “yes” to remove the virtual machine from the inventory.
The virtual machine will be removed from the vCenter inventory, but the virtual machine is still around. Don’t delete it!
At this point, all you have to do is add the virtual machine back into the vCenter.
- go to Home->Inventory->Datastores
- to find the datastore where the virtual machine resides
- click on the datastore
- click on “Browse this datastore”
- you will see a dialog called “Datastore Browser – [datastorename]” with a list of folders that represent the virtual machines that are stored there
- once you find the virtual machine you are looking for, double-click it on the right-side panel or single-click it on the left-side panel.
- right-click the vmx file for that virtual machine and click on “Add to Inventory”
- the name should be filled in and you can select the location where the virtual machine will go in your inventory and click “Next”
- now you can select which host or cluster to place your virtual machine in and then click “Next”
- you are given a review of your selections. At this point, click on “Finish” and the virtual machine will be added back into the vCenter inventory
At this point, click on the virtual machine that you just added back into inventory and you will see that the “Edit virtual machine settings” have returned to the GUI and you can now remove the ISO or DVD-ROM from your virtual machine and bring it back on-line.
I think this is a bug introduced in version 4.1 of the product, but I no longer have access to 4.0 or earlier versions to verify that. If anyone cares to investigate and share your results here, I would appreciate it.