Set default to podman

[chevdor]

See #23

This is more than just defaulting to podman.
There seem to be issues with podman related to the cache temp folder.

TODO:

Here is the list of changes required when the engine is set to podman:

• turn on --no-cache
• align UID/GID
• warn the user that in case of issue, adding --root may help

[trusch]

@chevdor Can you elaborate on whats the issue that requires --no-cache? I see that it is set by default now but I'd like to understand the issue since this could significantly increase build times.

[chevdor]

The cache requires some mapping to temp folders and there are issues with those.
You can check the issues I opened in the podman repo.
Without --no-cache it is very likely it will not work out of the box with podman.

[andresilva]

FWIW I needed to use --root to work with podman. Not sure if that's something that everyone needs or if it's specific to my setup. Without the flag it would fail while trying to create the target directory.

[chevdor]

Ok, thanks for the report @andresilva
Some flags are "turned on" automatically when using podman to ensure it works for the user without headache.
I am reluctant however to set --root by default.

I think this is the typical issue related to UID/GID+Permissions not matching between container and host.

Using root is the hammer option but good to hear that it works at least.

A better option to investigate and to remove the requirement for --root would be to take care of aligning the UID/GID.