[Solved] LXD 3.21, container refuses to start

Hi,
One of my container based on debian refuses to start after an update. The others based on Ubuntu/Arch/Alpine are starting fine.

$ lxc start voip1
Error: Failed to run: /snap/lxd/current/bin/lxd forkstart voip1 /var/snap/lxd/common/lxd/containers /var/snap/lxd/common/lxd/logs/voip1/lxc.conf: 
Try `lxc info --show-log voip1` for more info



$ lxc info --show-log voip1
Name: voip1
Location: none
Remote: unix://
Architecture: x86_64
Created: 2019/09/02 01:06 UTC
Status: Stopped
Type: container
Profiles: vlan200profile

Log:

lxc voip1 20200221162926.972 WARN     cgfsng - cgroups/cgfsng.c:chowmod:1525 - No such file or directory - Failed to chown(/sys/fs/cgroup/unified//lxc.payload/voip1/memory.oom.group, 1000000000, 0)
lxc voip1 20200221162927.710 ERROR    dir - storage/dir.c:dir_mount:198 - No such file or directory - Failed to mount "/var/snap/lxd/common/lxd/containers/voip1/rootfs" on "/var/snap/lxd/common/lxc/"
lxc voip1 20200221162927.711 ERROR    conf - conf.c:lxc_mount_rootfs:1353 - Failed to mount rootfs "/var/snap/lxd/common/lxd/containers/voip1/rootfs" onto "/var/snap/lxd/common/lxc/" with options "(null)"
lxc voip1 20200221162927.711 ERROR    conf - conf.c:lxc_setup_rootfs_prepare_root:3447 - Failed to setup rootfs for
lxc voip1 20200221162927.712 ERROR    conf - conf.c:lxc_setup:3550 - Failed to setup rootfs
lxc voip1 20200221162927.712 ERROR    start - start.c:do_start:1321 - Failed to setup container "voip1"
lxc voip1 20200221162927.713 ERROR    sync - sync.c:__sync_wait:62 - An error occurred in another process (expected sequence number 5)
lxc voip1 20200221162927.715 WARN     network - network.c:lxc_delete_network_priv:3377 - Failed to rename interface with index 76 from "eth0" to its initial name "veth82ef4982"
lxc voip1 20200221162927.716 ERROR    lxccontainer - lxccontainer.c:wait_on_daemonized_start:873 - Received container state "ABORTING" instead of "RUNNING"
lxc voip1 20200221162927.719 ERROR    start - start.c:__lxc_start:2039 - Failed to spawn container "voip1"
lxc 20200221162927.448 WARN     commands - commands.c:lxc_cmd_rsp_recv:135 - Connection reset by peer - Failed to receive response for command "get_state"
lxc voip1 20200221162928.185 ERROR    conf - conf.c:run_buffer:352 - Script exited with status 1
lxc voip1 20200221162928.185 ERROR    start - start.c:lxc_fini:1064 - Failed to run lxc.hook.post-stop for container "voip1"

The zfs dataset is mounted correctly,

# ls -l /var/snap/lxd/common/lxd/containers/voip1/rootfs
total 186
drwxr-xr-x  2 1000000 1000000 115 Sep 13 22:53 bin
drwxr-xr-x  2 1000000 1000000   2 Oct 20  2018 boot
drwxr-xr-x  4 1000000 1000000  15 Jan 20  2019 dev
drwxr-xr-x 86 1000000 1000000 164 Feb 21 21:38 etc
drwxr-xr-x  2 1000000 1000000   2 Oct 20  2018 home
drwxr-xr-x  9 1000000 1000000   9 Jan 20  2019 lib
drwxr-xr-x  2 1000000 1000000   3 Feb 17  2019 lib64
drwxr-xr-x  2 1000000 1000000   2 Jan 20  2019 media
drwxr-xr-x  2 1000000 1000000   2 Jan 20  2019 mnt
drwxr-xr-x  2 1000000 1000000   2 Jan 20  2019 opt
drwxr-xr-x  2 1000000 1000000   2 Oct 20  2018 proc
drwx------  3 1000000 1000000  15 Feb  9 17:42 root
drwxr-xr-x  2 1000000 1000000   2 Jan 20  2019 run
drwxr-xr-x  2 1000000 1000000 107 Sep 13 22:53 sbin
drwxr-xr-x  2 1000000 1000000   2 Jan 20  2019 srv
drwxr-xr-x  2 1000000 1000000   2 Oct 20  2018 sys
drwxrwxrwt  8 1000000 1000000   8 Feb 21 21:38 tmp
drwxr-xr-x 10 1000000 1000000  10 Jan 20  2019 usr
drwxr-xr-x 12 1000000 1000000  14 Jan 20  2019 var

The container config is like so,

# lxc config show voip1
architecture: x86_64
config:
  boot.autostart: "true"
  image.architecture: amd64
  image.description: Debian stretch amd64 (20190120_05:25)
  image.os: Debian
  image.release: stretch
  image.serial: "20190120_05:25"
  volatile.base_image: 762e995c489406f4b88114e856c989e5e2429b5e554ea4ce0a34e4fae7eaafff
  volatile.idmap.base: "0"
  volatile.idmap.current: '[{"Isuid":true,"Isgid":false,"Hostid":1000000,"Nsid":0,"Maprange":1000000000},{"Isuid":false,"Isgid":true,"Hostid":1000000,"Nsid":0,"Maprange":1000000000}]'
  volatile.idmap.next: '[{"Isuid":true,"Isgid":false,"Hostid":1000000,"Nsid":0,"Maprange":1000000000},{"Isuid":false,"Isgid":true,"Hostid":1000000,"Nsid":0,"Maprange":1000000000}]'
  volatile.last_state.idmap: '[{"Isuid":true,"Isgid":true,"Hostid":1000000,"Nsid":0,"Maprange":1000000000}]'
  volatile.last_state.power: RUNNING
devices: {}
ephemeral: false
profiles:
- vlan200profile
stateful: false
description: ""

Is there any way to make it start?

I was able to solve it by doing,

zfs umount /var/snap/lxd/common/lxd/storage-pools/lxd/containers/voip1
rm  /var/snap/lxd/common/lxd/storage-pools/lxd/containers/voip1/backup.yaml

It is starting now.