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

LXD
1

Background

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.

Question

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
config:
  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
devices:
  eth0:
    name: eth0
    nictype: bridged
    parent: br0
    type: nic
  root:
    path: /
    pool: lxcDefaultPool
    type: disk
  shareFolder:
    path: /home/ubuntu/media
    source: /home/share_user/media
    type: disk
ephemeral: false
profiles:
- default
stateful: false
description: ""
2

Hi

The main config options are here

And devices are further down on same page

3

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

4

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