Can't detach disk

Community Support
1

Hello everyone,

I have installed opennebula and I can’t detach a disk form an instance that I have running. The VM has two disks attached, disk 0, a Debian ISO cd and disk 1,a 50GB volatile drive (where I installed Debian). The thing is that now that Debian is installed, I want to detach the CD ISO so the Debian OS that I installed can boot. So far it boots directly the CD ISO, not letting me detach it. I don’t get any errors, just a message saying “detaching”, then I refresh and it is as before. I tried to detach it via command line, and again, the command seems to execute with no errors, but when I list the disks I see the CD ISO still there. Could someone give me a hand with this?

Thanks a lot and regards

2

Hi,

You should check for clues what’s going on in the oned logfile /var/log/one/oned.log the reason for not detaching the disk should be logged there.

Best Regards,
Anton Todorov

3

Hello Anton,

Thanks for your answer. Here’s what the log says:

Fri May 12 15:49:00 2017 [Z0][VMM][D]: Message received: LOG E 34 detach_disk: Command “virsh --connect qemu:///system detach-disk --domain one-34 --target hda” failed: error: Failed to detach disk

Fri May 12 15:49:00 2017 [Z0][VMM][D]: Message received: LOG I 34 error: Operation not supported: This type of disk cannot be hot unplugged

Fri May 12 15:49:00 2017 [Z0][VMM][D]: Message received: LOG E 34 Could not detach hda from one-34

Fri May 12 15:49:00 2017 [Z0][VMM][D]: Message received: LOG I 34 ExitCode: 1

Fri May 12 15:49:00 2017 [Z0][VMM][D]: Message received: LOG I 34 Failed to execute virtualization driver operation: detach_disk.

Fri May 12 15:49:00 2017 [Z0][VMM][D]: Message received: DETACHDISK FAILURE 34 Could not detach hda from one-34

Any clues why this disk cannot be hot unplugged? Is there another way of unplugging? I’ve tried shutting the machine down and when doing so, the detach option dissapears

4

I also tried this, with same results:

virsh --connect qemu:///system detach-disk --domain one-34 --target hda

5

Hi Francisco,

The “hd” prefiexd devices are using virtio-ide interface which hasn’t hotplug option. You should be able to detach the disk while the VM is powered off though.

Best Regards,
Anton Todorov

6

Also you can change the boot order when the VM is in powered-off state: VM details -> Conf -> Update Configuration(green button)

Best,
Anton

7

Hi Anton,

thanks a lot for your prompt answer. I shutdown the machine and went to update configuration, but then I get the following error:
Configuration cannot be updated in status SHUTDOWN_POWEROFF

Should I put it in the “Terminate” or “Undeploy” state rather that shutdown?

8

Hm, you should definitely can attach/detach ide disk in powered off state. For changing boot options like boot order ‘undeploy’ should be ok. Terminate will delete the VM.

Best,
Anton

9

I tried again, and this time the machine is in state Poweroff. I no longer get the error form before, although the changes don’t apply when checking afterwards. The boot order remains the same

10

Instead of changing the order I removed the disk while Poweroff, and I can now boot correctly into my OS. Thanks a lot for the quick answers!

Francisco