XenServer XCP when control domain has hold of a VDI

^{Created: 2020-05-06 23:44:32 | Last modified: 2020-05-07 00:22:11} ^{| By: Nova}
^{Access: Read}^{| Visibility: Public}^{| Views: 141}^{| Rating: N/A}^{| Tags: xenserver}
Remove the XenServer or XCP control domain having a hold on a storage VDI

With XenServer/XCP we did a meta data restore to restore a number of virtual machines on a storage repository when creating a clean install of XCP. All the VMs came up fine but the control domain still had a lock on the disk VDIs. We are unable to migrate the volume or perform other operations until this lock is removed.

Here is some instructions of how to remove the control domain lock on these;

List the domains to get the Dom0 UUID

list_domains

id |                                 uuid |  state
 0 | ded17027-b863-47d4-9d63-b3b2c7daee46 |     R 
 1 | f0535e79-01b3-51c5-015d-d217c4a7f63c |    B  
 3 | 8bea4bb6-bda0-af7f-0373-36f6f905680e |    B H
 4 | fd02481b-756f-b593-2e75-dff0fe08075f |    B  
 5 | b7ac7792-efba-dd88-beec-feaf87bb84dc |    B H
 8 | c642a181-aa97-23dc-9030-4879b7a4d52b |    B

Next list all of the vbd (Virtual Block Device) locks for the Dom0 UUID and get the VBD UUID

xe vbd-list vm-uuid=ded17027-b863-47d4-9d63-b3b2c7daee46

uuid ( RO)             : d3eadc3c-96c3-7031-1894-0f31d2d8b255
          vm-uuid ( RO): ded17027-b863-47d4-9d63-b3b2c7daee46
    vm-name-label ( RO): Control domain on host: nzvz2
         vdi-uuid ( RO): efca45ac-6bed-47bc-9373-1417ee41f8d5
            empty ( RO): false
           device ( RO): sm/backend/e9b8b43d-03ab-8947-2cf8-b8d867dbf30a/6t36222-2352-47bc-9373-1417ee41f8d5


uuid ( RO)             : 013734c3-c6df-6c55-bd43-fdeb33eb35e7
          vm-uuid ( RO): ded17027-b863-47d4-9d63-b3b2c7daee46
    vm-name-label ( RO): Control domain on host: nzvz2
         vdi-uuid ( RO): d9771f37-b0a3-4801-9a2f-aef8fc218e26
            empty ( RO): false
           device ( RO): sm/backend/e9b8b43d-03ab-8947-2cf8-b8d867dbf30a/d9771f37-323-4801-9a2f-aef8fc218e26

Now try and detach the VBD. If this doesn't and you get a "The device is not currently attached" message you will need to destroy the VBD, this doesn't delete the VDI/Disk itself, just the lock that Dom0 has on it

xe vbd-unplug uuid=013734c3-c6df-6c55-bd43-fdeb33eb35e7

The device is not currently attached
device: 013734c3-c6df-6c55-bd43-fdeb33eb35e7

The above failed, destroy the VBD, no output is displayed. When running the vbd-list again you will be able to see that the lock has gone.

xe vbd-destroy uuid=013734c3-c6df-6c55-bd43-fdeb33eb35e7