LXC Crash -- how to troubleshoot?

LXD
1

Dear Experts,

LXC has crashed on my server and I try to retrieve at least one VM. I made many attempts without any success and I am not able anymore to diagnose if I will be able to get the VM up again.

Description: Ubuntu 20.04.5 LTS
Release: 20.04
Codename: focal

Your help would be very appreciated to troubleshoot the situation.

lxc list
+----------------+---------+------+------+-----------------+-----------+
|      NAME      |  STATE  | IPV4 | IPV6 |      TYPE       | SNAPSHOTS |
+----------------+---------+------+------+-----------------+-----------+
| my_vm        | STOPPED |      |      | VIRTUAL-MACHINE | 0         |
+----------------+---------+------+------+-----------------+-----------+

I cannot start the VM, storage pool doesn’t exist anymore.

lxc start my_vm
Error: Storage pool "default" unavailable on this server

Everything was created using Maas that I have removed because it has crashed.

snap list
Name    Version      Rev    Tracking       Publisher   Notes
core18  20220831     2566   latest/stable  canonicalâś“  base
core20  20220923     1646   latest/stable  canonicalâś“  base
lxd     5.6-794016a  23680  latest/stable  canonicalâś“  -
snapd   2.57.2       17029  latest/stable  canonicalâś“  snapd
2

Please can you show output of:

lxc storage show default

And contents of /var/snap/lxd/common/lxd/logs/lxd.log

3

Sure.

  size: 1500GB
  source: /var/snap/lxd/common/lxd/disks/default.img
  zfs.pool_name: default
description: ""
name: default
driver: zfs
used_by:
- /1.0/images/deed74e286af957cdeb6a1020359b82c515d1e1697f31e025daba4215ee25940
- /1.0/instances/my_vm?project=maas
- /1.0/profiles/default
- /1.0/storage-pools/default/volumes/custom/maas-04469fd3-eaaf-4f89-b9bd-bd050bdfb0d8
- /1.0/storage-pools/default/volumes/custom/maas-0bf589e1-e883-4787-bd43-ea77e5705b71
...
status: Unavailable
locations:
- none

time="2022-10-05T08:34:38Z" level=error msg="Failed mounting storage pool" err="Failed to run: zpool import -f -d /var/snap/lxd/common/lxd/disks default: exit status 1 (cannot import 'default': no such pool available)" pool=default
4

Does /var/snap/lxd/common/lxd/disks/default.img exist?

5

no, it does not.

6

OK so there’s the problem. Any idea where its gone? Do you have backups?

What happened on the server?

7

No idea, probably I lost everything.
Actually, I had an issue with another VM thus I decided to remove apparmor which deleted snap.

8

Ah yes if you removed the snap package then it would delete any loop files which are stored within it.

Snap may have created a snapshot record on removal (if not run with --purge) see

9

Many thanks for your help Thomas

1 Like