Error: Failed to run: /snap/lxd/current/bin/lxd forkstart u20 /var/snap/lxd/common/lxd/containers /var/snap/lxd/common/lxd/logs/u20/lxc.conf

I have issues creating a container. There are similar posts, but none of the answers solved my problem.

Here are some details.

✗ lxc info --show-log u20
Name: u20
Status: STOPPED
Type: container
Architecture: x86_64
Created: 2023/09/18 00:58 CEST
Last Used: 2023/09/18 09:56 CEST

Log:

lxc u20 20230918075611.794 WARN     conf - ../src/src/lxc/conf.c:lxc_map_ids:3621 - newuidmap binary is missing
lxc u20 20230918075611.795 WARN     conf - ../src/src/lxc/conf.c:lxc_map_ids:3627 - newgidmap binary is missing
lxc u20 20230918075611.797 WARN     conf - ../src/src/lxc/conf.c:lxc_map_ids:3621 - newuidmap binary is missing
lxc u20 20230918075611.797 WARN     conf - ../src/src/lxc/conf.c:lxc_map_ids:3627 - newgidmap binary is missing
lxc u20 20230918075611.896 ERROR    cgfsng - ../src/src/lxc/cgroups/cgfsng.c:cgfsng_mount:2139 - No such file or directory - Failed to create cgroup at_mnt 24()
lxc u20 20230918075611.896 ERROR    conf - ../src/src/lxc/conf.c:lxc_mount_auto_mounts:852 - No such file or directory - Failed to mount "/sys/fs/cgroup"
lxc u20 20230918075611.896 ERROR    conf - ../src/src/lxc/conf.c:lxc_setup:4433 - Failed to setup remaining automatic mounts
lxc u20 20230918075611.896 ERROR    start - ../src/src/lxc/start.c:do_start:1272 - Failed to setup container "u20"
lxc u20 20230918075611.896 ERROR    sync - ../src/src/lxc/sync.c:sync_wait:34 - An error occurred in another process (expected sequence number 4)
lxc u20 20230918075611.909 WARN     network - ../src/src/lxc/network.c:lxc_delete_network_priv:3631 - Failed to rename interface with index 0 from "eth0" to its initial name "veth7621ba36"
lxc u20 20230918075611.909 ERROR    lxccontainer - ../src/src/lxc/lxccontainer.c:wait_on_daemonized_start:878 - Received container state "ABORTING" instead of "RUNNING"
lxc u20 20230918075611.909 ERROR    start - ../src/src/lxc/start.c:__lxc_start:2107 - Failed to spawn container "u20"
lxc u20 20230918075611.909 WARN     start - ../src/src/lxc/start.c:lxc_abort:1036 - No such process - Failed to send SIGKILL via pidfd 19 for process 18637
lxc 20230918075612.856 ERROR    af_unix - ../src/src/lxc/af_unix.c:lxc_abstract_unix_recv_fds_iov:218 - Connection reset by peer - Failed to receive response
lxc 20230918075612.856 ERROR    commands - ../src/src/lxc/commands.c:lxc_cmd_rsp_recv_fds:128 - Failed to receive file descriptors for command "get_init_pid"

config:

✗ lxc config show u20 --expanded
architecture: x86_64
config:
  image.architecture: amd64
  image.description: ubuntu 20.04 LTS amd64 (release) (20230908)
  image.label: release
  image.os: ubuntu
  image.release: focal
  image.serial: "20230908"
  image.type: squashfs
  image.version: "20.04"
  volatile.base_image: 67c172d007a3787c92ac4fa8de30c68d3540743f8235882c46460bbe68aa3546
  volatile.cloud-init.instance-id: 7e1f4ff3-8a16-447b-9fb7-90f467fc98af
  volatile.eth0.hwaddr: 00:16:3e:17:17:3d
  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: '[]'
  volatile.last_state.power: STOPPED
  volatile.last_state.ready: "false"
  volatile.uuid: 49d8d4c9-70fb-46d2-bd7b-f30fd95ba47b
  volatile.uuid.generation: 49d8d4c9-70fb-46d2-bd7b-f30fd95ba47b
devices:
  eth0:
    name: eth0
    network: lxdbr0
    type: nic
  root:
    path: /
    pool: default
    type: disk
ephemeral: false
profiles:
- default
stateful: false
description: ""

Running lxc monitor:

➜ lxc monitor --pretty
DEBUG  [2023-09-18T10:02:31+02:00] Event listener server handler started         id=5ac58b0f-cb99-41d1-ad29-c55c50d7e569 local=/var/snap/lxd/common/lxd/unix.socket remote=@
DEBUG  [2023-09-18T10:02:38+02:00] Handling API request                          ip=@ method=GET protocol=unix url=/1.0 username=decoder
DEBUG  [2023-09-18T10:02:38+02:00] Handling API request                          ip=@ method=GET protocol=unix url=/1.0/instances/u20 username=decoder
DEBUG  [2023-09-18T10:02:38+02:00] Handling API request                          ip=@ method=GET protocol=unix url=/1.0/events username=decoder
DEBUG  [2023-09-18T10:02:38+02:00] Event listener server handler started         id=62c72d16-4272-4117-b22f-725ed78cc59c local=/var/snap/lxd/common/lxd/unix.socket remote=@
DEBUG  [2023-09-18T10:02:38+02:00] Handling API request                          ip=@ method=PUT protocol=unix url=/1.0/instances/u20/state username=decoder
DEBUG  [2023-09-18T10:02:38+02:00] Start started                                 instance=u20 instanceType=container project=default stateful=false
DEBUG  [2023-09-18T10:02:38+02:00] New operation                                 class=task description="Starting instance" operation=a844e6cc-7198-4836-be7b-dd8be2760d9e project=default
INFO   [2023-09-18T10:02:38+02:00] ID: a844e6cc-7198-4836-be7b-dd8be2760d9e, Class: task, Description: Starting instance  CreatedAt="2023-09-18 10:02:38.716451633 +0200 CEST" Err= Location=none MayCancel=false Metadata="map[]" Resources="map[instances:[/1.0/instances/u20]]" Status=Running StatusCode=Running UpdatedAt="2023-09-18 10:02:38.716451633 +0200 CEST"
DEBUG  [2023-09-18T10:02:38+02:00] Started operation                             class=task description="Starting instance" operation=a844e6cc-7198-4836-be7b-dd8be2760d9e project=default
DEBUG  [2023-09-18T10:02:38+02:00] Instance operation lock created               action=start instance=u20 project=default reusable=false
INFO   [2023-09-18T10:02:38+02:00] Starting instance                             action=start created="2023-09-17 22:58:20.265711579 +0000 UTC" ephemeral=false instance=u20 instanceType=container project=default stateful=false used="2023-09-18 07:56:11.713556508 +0000 UTC"
INFO   [2023-09-18T10:02:38+02:00] ID: a844e6cc-7198-4836-be7b-dd8be2760d9e, Class: task, Description: Starting instance  CreatedAt="2023-09-18 10:02:38.716451633 +0200 CEST" Err= Location=none MayCancel=false Metadata="map[]" Resources="map[instances:[/1.0/instances/u20]]" Status=Pending StatusCode=Pending UpdatedAt="2023-09-18 10:02:38.716451633 +0200 CEST"
DEBUG  [2023-09-18T10:02:38+02:00] Handling API request                          ip=@ method=GET protocol=unix url=/1.0/operations/a844e6cc-7198-4836-be7b-dd8be2760d9e username=decoder
DEBUG  [2023-09-18T10:02:38+02:00] MountInstance started                         driver=btrfs instance=u20 pool=default project=default
DEBUG  [2023-09-18T10:02:38+02:00] MountInstance finished                        driver=btrfs instance=u20 pool=default project=default
DEBUG  [2023-09-18T10:02:38+02:00] Starting device                               device=eth0 instance=u20 instanceType=container project=default type=nic
DEBUG  [2023-09-18T10:02:38+02:00] Scheduler: network: veth49994a65 has been added: updating network priorities
DEBUG  [2023-09-18T10:02:38+02:00] Scheduler: network: vetha1ac6832 has been added: updating network priorities
DEBUG  [2023-09-18T10:02:38+02:00] UpdateInstanceBackupFile started              driver=btrfs instance=u20 pool=default project=default
DEBUG  [2023-09-18T10:02:38+02:00] Starting device                               device=root instance=u20 instanceType=container project=default type=disk
DEBUG  [2023-09-18T10:02:38+02:00] Skipping unmount as in use                    driver=btrfs pool=default refCount=1 volName=u20
DEBUG  [2023-09-18T10:02:38+02:00] UpdateInstanceBackupFile finished             driver=btrfs instance=u20 pool=default project=default
DEBUG  [2023-09-18T10:02:38+02:00] Handling API request                          ip=@ method=GET protocol=unix url="/internal/containers/u20/onstart?project=default" username=root
DEBUG  [2023-09-18T10:02:38+02:00] Scheduler: container u20 started: re-balancing
DEBUG  [2023-09-18T10:02:38+02:00] Instance operation lock finished              action=start err="Failed to run: /snap/lxd/current/bin/lxd forkstart u20 /var/snap/lxd/common/lxd/containers /var/snap/lxd/common/lxd/logs/u20/lxc.conf: exit status 1" instance=u20 project=default reusable=false
ERROR  [2023-09-18T10:02:38+02:00] Failed starting instance                      action=start created="2023-09-17 22:58:20.265711579 +0000 UTC" ephemeral=false instance=u20 instanceType=container project=default stateful=false used="2023-09-18 07:56:11.713556508 +0000 UTC"
DEBUG  [2023-09-18T10:02:38+02:00] Failure for operation                         class=task description="Starting instance" err="Failed to run: /snap/lxd/current/bin/lxd forkstart u20 /var/snap/lxd/common/lxd/containers /var/snap/lxd/common/lxd/logs/u20/lxc.conf: exit status 1" operation=a844e6cc-7198-4836-be7b-dd8be2760d9e project=default
DEBUG  [2023-09-18T10:02:38+02:00] Start finished                                instance=u20 instanceType=container project=default stateful=false
DEBUG  [2023-09-18T10:02:38+02:00] Event listener server handler stopped         listener=62c72d16-4272-4117-b22f-725ed78cc59c local=/var/snap/lxd/common/lxd/unix.socket remote=@
INFO   [2023-09-18T10:02:38+02:00] ID: a844e6cc-7198-4836-be7b-dd8be2760d9e, Class: task, Description: Starting instance  CreatedAt="2023-09-18 10:02:38.716451633 +0200 CEST" Err="Failed to run: /snap/lxd/current/bin/lxd forkstart u20 /var/snap/lxd/common/lxd/containers /var/snap/lxd/common/lxd/logs/u20/lxc.conf: exit status 1" Location=none MayCancel=false Metadata="map[]" Resources="map[instances:[/1.0/instances/u20]]" Status=Failure StatusCode=Failure UpdatedAt="2023-09-18 10:02:38.716451633 +0200 CEST"
DEBUG  [2023-09-18T10:02:39+02:00] Handling API request                          ip=@ method=GET protocol=unix url="/internal/containers/u20/onstopns?netns=%2Fproc%2F25164%2Ffd%2F4&project=default&target=stop" username=root
DEBUG  [2023-09-18T10:02:39+02:00] Instance initiated stop                       action=stop instance=u20 instanceType=container project=default
DEBUG  [2023-09-18T10:02:39+02:00] Instance operation lock created               action=stop instance=u20 project=default reusable=false
DEBUG  [2023-09-18T10:02:39+02:00] Stopping device                               device=eth0 instance=u20 instanceType=container project=default type=nic
DEBUG  [2023-09-18T10:02:39+02:00] Handling API request                          ip=@ method=GET protocol=unix url="/internal/containers/u20/onstop?project=default&target=stop" username=root
DEBUG  [2023-09-18T10:02:39+02:00] Instance operation lock inherited for stop    action=stop instance=u20 instanceType=container project=default
DEBUG  [2023-09-18T10:02:39+02:00] Instance stopped, cleaning up                 instance=u20 instanceType=container project=default
DEBUG  [2023-09-18T10:02:39+02:00] Stopping device                               device=root instance=u20 instanceType=container project=default type=disk
DEBUG  [2023-09-18T10:02:39+02:00] UnmountInstance started                       driver=btrfs instance=u20 pool=default project=default
DEBUG  [2023-09-18T10:02:39+02:00] UnmountInstance finished                      driver=btrfs instance=u20 pool=default project=default
DEBUG  [2023-09-18T10:02:39+02:00] Scheduler: container u20 stopped: re-balancing
DEBUG  [2023-09-18T10:02:39+02:00] Instance operation lock finished              action=stop err="<nil>" instance=u20 project=default reusable=false
INFO   [2023-09-18T10:02:39+02:00] Shut down instance                            action=stop created="2023-09-17 22:58:20.265711579 +0000 UTC" ephemeral=false instance=u20 instanceType=container project=default stateful=false used="2023-09-18 08:02:38.791154927 +0000 UTC"
INFO   [2023-09-18T10:02:39+02:00] Action: instance-shutdown, Source: /1.0/instances/u20