`unshare` failure when building on `ubuntu:jammy` container

[marip8]

I'm trying to build a few packages using this action on an ubuntu:jammy Docker container, rather than the Github 22.04 runner, and I'm running into some issues with unshare:

sbuild (Debian sbuild) 0.84.2~ubuntu2204+3 (28 December 2022) on 75794b96caf5

  +===================================================================================+
  | ros-humble-octomap 1.9.8-2023.11.08.00.51 (amd64) Wed, 08 Nov 2023 00:51:04 +0000 |
  +===================================================================================+

  Package: ros-humble-octomap
  Version: 1.9.8-2023.11.08.00.51
  Source Version: 1.9.8-2023.11.08.00.51
  Distribution: jammy
  Machine Architecture: amd64
  Host Architecture: amd64
  Build Architecture: amd64
  Build Type: binary

  E: unshare failed: 
  E: unable to to unshare
  E: Error creating chroot session: skipping ros-humble-octomap

  +------------------------------------------------------------------------------+
  | Summary                                                                      |
  +------------------------------------------------------------------------------+

  Build Architecture: amd64
  Build Type: binary
  Build-Space: 0
  Build-Time: 0
  Distribution: jammy
  Fail-Stage: create-session
  Host Architecture: amd64
  Install-Time: 0
  Job: /__w/tesseract_packages/tesseract_packages/src/octomap/ros-humble-octomap_1.9.8-2023.11.08.00.51.dsc
  Machine Architecture: amd64
  Package: ros-humble-octomap
  Package-Time: 0
  Source-Version: 1.9.8-2023.11.08.00.51
  Space: 0
  Status: failed
  Version: 1.9.8-2023.11.08.00.51
  --------------------------------------------------------------------------------
  Finished at 2023-11-08T00:51:04Z
  Build needed 00:00:00, 0k disk space
  E: Error creating chroot session: skipping ros-humble-octomap
  Error: Process completed with exit code 1.

Here is the link to the full action log. I'm fairly new to sbuild, so I'm not entirely sure what is going wrong here.

[jspricke]

Afaik Docker does not support user namespaces (unshare syscall), is there any reason you want to use Docker?

[marip8]

Not particularly. I don't exactly know how the Github runners are configured, so I thought it would be "cleaner" to try to run this action out of a container. If it's not easily supported, then I don't think I have a problem running it on the Github runners.

Does this action only work with 22.04, or can it also support 20.04?

[jspricke]

Not particularly. I don't exactly know how the Github runners are configured, so I thought it would be "cleaner" to try to run this action out of a container. If it's not easily supported, then I don't think I have a problem running it on the Github runners.

Note that user namespaces are cleaner then Docker.

Does this action only work with 22.04, or can it also support 20.04?

Only 22.04.