Where do I find documentation for the fields listed in "lxc config show --expanded [instanceName]"?


Just a quick question regarding LXD documentation (likely being a dummy).

When I run lxc config show --expanded myInstanceName I get the results as expected (output at bottom of this post).

I’d like to run a Docker container inside a container, and my containers are unprivileged (I confirmed that based on this post).

To run Docker inside an unprivileged container, I apparently need to ensure keyctl is enabled, and nesting, too (based on this article).

With that in mind, my next port of call was to check the documentation so that I could: learn about exactly what these fields do before blindly setting them (although the latter is fairly self-explanatory); find out how to set these fields in my config.


I tried Googling “lxd config man” which returns this page, but I can’t find any reference to keyctl, and there’s more than one reference to nesting referring to both app_armour and seccomp, I’m not sure which to use.

I tried running lxc config set --help and lxc config set --help --sub-commands but this is just information on how to set fields, not a list all of all fields and their descriptions.

So, as I said, I’m likely being a dummy but my questions are:

  • Where do I get the documentation listing all the definable fields (particularly keyctl) and their purposes? (I imagine it’s likely I have found the correct documentation but keyctl goes by a different name or similar)
  • A bit against the “teach a man to fish” ethos of this post, but for my particular problem, what are the commands I need to run regarding nesting and keyctl to allow Docker inside LXC/LXD?

Thanks in advance for any help at all! :slight_smile:

Results for lxc config show --expanded myInstanceName

architecture: x86_64
  image.architecture: amd64
  image.description: ubuntu 20.04 LTS amd64 (release) (20210927)
  image.label: release
  image.os: ubuntu
  image.release: focal
  image.serial: "20210927"
  image.type: squashfs
  image.version: "20.04"
  volatile.base_image: 56296ba81a6fb502c634697a840d7957c3d2aa1a1805820e605ed21475058851
  volatile.eth0.host_name: vethfc3f5a2d
  volatile.eth0.hwaddr: 00:16:3e:f5:23:7a
  volatile.idmap.base: "0"
  volatile.idmap.current: '[{"Isuid":true,"Isgid":false,"Hostid":100000,"Nsid":0,"Maprange":65536},{"Isuid":false,"Isgid":true,"Hostid":100000,"Nsid":0,"Maprange":65536}]'
  volatile.idmap.next: '[{"Isuid":true,"Isgid":false,"Hostid":100000,"Nsid":0,"Maprange":65536},{"Isuid":false,"Isgid":true,"Hostid":100000,"Nsid":0,"Maprange":65536}]'
  volatile.last_state.idmap: '[{"Isuid":true,"Isgid":false,"Hostid":100000,"Nsid":0,"Maprange":65536},{"Isuid":false,"Isgid":true,"Hostid":100000,"Nsid":0,"Maprange":65536}]'
  volatile.last_state.power: RUNNING
  volatile.uuid: d7bc7358-b05f-46dc-95a1-51a28c30f553
    name: eth0
    nictype: bridged
    parent: br0
    type: nic
    path: /
    pool: lxcDefaultPool
    type: disk
    path: /home/ubuntu/media
    source: /home/share_user/media
    type: disk
ephemeral: false
- default
stateful: false
description: ""


The main config options are here

And devices are further down on same page

Also remember that lxc and lxd are different projects so you can’t use lxc docs for lxd.

I stumbled upon this while looking for the same information. The document has moved: Instance options - LXD documentation