Failing to start unprivileged container (QNAP)


I’m having difficulties to run a unprivileged container using LXD, when I launch an alpine container (teste) with this config, it fails asking for permissions on the /var/lib/lxd, permissions that are already there, here is the step by step:

$ lxc config show teste

    architecture: x86_64
      boot.autostart: "true"
      image.architecture: amd64
      image.description: Alpine edge amd64 (20210906_13:00)
      image.os: Alpine
      image.release: edge
      image.serial: "20210906_13:00"
      image.type: squashfs
      image.variant: default
      security.idmap.base: "1000000"
      security.idmap.size: "65536"
      security.privileged: "false"
      volatile.base_image: a5cd77b17561dc20d7cefd3b482301dc43923b10fe6887a1a7593b77b7ac5e46
      volatile.idmap.base: "0"
      volatile.last_state.power: STOPPED
      volatile.uuid: 89f366b9-bc8d-4ac2-9a55-dfeb132f7184
    devices: {}
    ephemeral: false
    - default
    stateful: false
    description: ""

$ lxc start teste

Error: Failed to run: /path/to/lxd forkstart teste /var/lib/lxd/containers /var/log/lxd/teste/lxc.conf:
Try `lxc info --show-log teste` for more info

$ lxc info --show-log teste

Name: teste
Location: none
Remote: unix://
Architecture: x86_64
Created: 2021/09/23 15:55 UTC
Status: Stopped
Type: container
Profiles: default


lxc teste 20210924111701.964 WARN     cgfsng - cgroups/cgfsng.c:cg_hybrid_get_controllers:657 - Found hierarchy not under /sys/fs/cgroup: "/dev/cgroups_antivirus rw,relatime shared:146 - cgroup memory rw,memory
lxc teste 20210924111701.974 WARN     cgfsng - cgroups/cgfsng.c:mkdir_eexist_on_last:1152 - File exists - Failed to create directory "/sys/fs/cgroup/cpuset//lxc.monitor.teste"
lxc teste 20210924111701.993 WARN     cgfsng - cgroups/cgfsng.c:mkdir_eexist_on_last:1152 - File exists - Failed to create directory "/sys/fs/cgroup/cpuset//lxc.payload.teste"
lxc teste 20210924111702.145 ERROR    start - start.c:print_top_failing_dir:98 - Permission denied - Could not access /var/lib/lxd. Please grant it x access, or add an ACL for the container root
lxc teste 20210924111702.162 ERROR    sync - sync.c:__sync_wait:36 - An error occurred in another process (expected sequence number 3)
lxc teste 20210924111702.164 WARN     network - network.c:lxc_delete_network_priv:3185 - Failed to rename interface with index 3 from "eth0" to its initial name "veth4d0ebce6"
lxc teste 20210924111702.166 ERROR    start - start.c:__lxc_start:1999 - Failed to spawn container "teste"
lxc teste 20210924111702.166 WARN     start - start.c:lxc_abort:1013 - No such process - Failed to send SIGKILL via pidfd 26 for process 2715474
lxc teste 20210924111702.198 ERROR    lxccontainer - lxccontainer.c:wait_on_daemonized_start:860 - Received container state "ABORTING" instead of "RUNNING"
lxc 20210924111702.391 WARN     commands - commands.c:lxc_cmd_rsp_recv:126 - Connection reset by peer - Failed to receive response for command "get_state"

The /var/lib/lxd already has x permission for everyone, so I’ve tried follow the permissions from the container rootfs using namei:

$ namei -mvo /var/lib/lxd/storage-pools/default/containers/teste/rootfs/

Permission User Group Dir
drwxrwxr-x root root var
drwxr-xr-x root root lib
drwx–x–x root root lxd
drwx–x–x root root storage-pools
drwx–x–x root root default
drwx–x–x root root containers
d–x------ root root teste
drwxr-xr-x 1000000 1000000 rootfs

The only directory without x or ACL for others is the /var/lib/lxd/storage-pools/default/containers/teste, I’ve tried to change and test if that could fix the errors, but every time I try to start the container the permissions change back to the original d–x------

So here is where I’m stuck and asking for help, any input is appreciated!

Also just to be clear my setup is a QNAP NAS, so is a heavily customized Linux, I’m aware this could be de cause why only privileged container are running.

Was this container originally a privileged one?

Can you show output of lxc storage show default.

For an example, this is what a container on a dir pool should look like:

namei -mvo /var/lib/lxd/storage-pools/default/containers/test_c1/rootfs/
f: /var/lib/lxd/storage-pools/default/containers/test_c1/rootfs/
drwxr-xr-x root    root /
drwxr-xr-x root    root var
drwxr-xr-x root    root lib
drwx--x--x root    root lxd
drwx--x--x root    root storage-pools
drwx--x--x root    root default
drwx--x--x root    root containers
d--x------ 1000000 root test_c1
drwxr-xr-x root    root rootfs

So the permission on d–x------ root root teste looks OK but the owner does not.

No, it was created as unprivileged from start.

  source: /var/lib/lxd/storage-pools/default
description: Default LXD storage pool
name: default
driver: dir
- /1.0/instances/server
- /1.0/instances/teste
- /1.0/profiles/default
- /1.0/profiles/tcs
status: Created
- none

Can you change the ownership of teste to 1000000:1000000?

Yes, but when I call lxc start teste the permissions and owner resets, I’ve tried setfacl to force new permissions, same problem.

Sorry, but I found the solution.

Everything was caused by directory ACL set by QNAP, I removed all ACL permissions and everything worked.

For anyone out there using QNAP, be aware that using container station on shared folder with “advanced permissions” a.k.a. ACL will broke LXD/LXC and even docker in some cases.

@tomp Thanks for the help and sorry for the wasted time!

1 Like

Excellent, for other readers could you show the command you run to fix this?

In a QTS (QNAP OS) LXD is part of package called Container Station, after installation you must choose a folder that will hold all container and images, lets assume you choose the directory apps, this means the software will create everything under /share/VOLUME_NAME/apps/container-station-data then make a LOT of symlinks.

The problem is that the /share/VOLUME_NAME/apps created by QTS Web Ui, sets ACL permissions, to solve just run:

$ setfacl -Rb /share/VOLUME_NAME/apps

And then everything worked, I tried adding ids to the ACL before but that didn’t work.

1 Like