The disk id_path isn't recorded correctly on commissioning

[Björn Tillenius]

This is with MAAS 2.7.0~rc1-8207-g.b148a8b9c.

After commissioning a machine, you'll see that the disks will have
id_paths like "pci-0000:00:1f.2-ata-1", when it should be something
like "/dev/disk/by-id/..."

This causes problems editing disk tags for example, since the validation
of id_path fails when adding a tag to the disk.

Note that this isn't visible with VMs using virtio disks, since virtio
doesn't implement /dev/disk/by-id/ and thus MAAS puts the normal
device path there.

[Caleb Ellis (caleb-ellis)]

I am not getting this behaviour - see attached video. Can you paste what's sent through the websocket and what's returned?

[Björn Tillenius (bjornt)]

Interesting.

You can see the websocket request and response here:

  https://pastebin.ubuntu.com/p/QPnjVmcHJ8/

[Björn Tillenius (bjornt)]

Ok, I think we've found the problem. It's a backend bug.

The problem is that when commissioning a machine, the id_path of a disk
get set to the wrong value. For example, one of the disks have and id_path
of "pci-0000:00:1f.2-ata-1", where it should be something like
"/dev/disk/by-id/...".

The reason you're not seeing the bug is that you use a VM with virtio disks.
The virtio driver doesn't support id paths, so none get reported to MAAS,
which in turn simply puts the normal device path there (e.g. "/dev/vda")

[Alberto Donato (ack)]

Field is being added in LXD code at https://github.com/lxc/lxd/pull/6719