Enable use of podman to run tests

[tomhughes]

This adds support for using podman to run tests - you just need to run systemctl --user enable --now podman.socket to enable the podman socket for your user and that you can run tests as normal.

Note that until test-kitchen/kitchen-dokken#323 is merged you need to set DOCKER_HOST=unix:///run/user/$(id -u)/podman/podman.sock in the environment to make it work.

[Firefishy]

I tested this on a Mac using podman machine... I was only able to get this to work after stripping out all the docker_host_url lines and just setting podman = true

Podman on Mac uses an unconventional socket.
DOCKER_HOST=unix:///var/folders/kv/sb3s4k3n0zq27rtr2yd_2lc00000gn/T/podman/podman-machine-default-api.sock
Podman can also set a /var/run/docker.sock symlink, but this isn't done by default due to requiring extra permissions.

[tomhughes]

That sounds like you were trying to use rootful podman not rootless.

On linux you can enable the system podman.socket which uses /run/podman/podman.sock and which /run/docker.sock points at (if you have podman-docker installed) or you can enable a per-user socket by starting the user podman.socket unit for a user.

The system one is only available to root so isn't very useful here while the per-user one is only available to the user that started it - there is no equivalent to the docker group on Ubuntu/Debian that allows everybody in it to access the global instance.

[Firefishy]

Likely complicated by the use of podman machine... But I appears to be rootless

podman info reports:

host:
  security:
    rootless: true

[tomhughes]

What do you mean by using podman machine though? You shouldn't be interacting with podman directly at all, just with kitchen by doing something like bundle exec kitchen test apache-ubuntu-2204.