1.6 rc2, fc30, rootless: warnings about missing crun

[edsantiago]

(Similar to, but not the same as, #4012)

podman-1.6.0-0.2.rc2.fc30 rootless outputs copious warnings by default:

$ podman images
WARN[0000] Error initializing configured OCI runtime crun: no valid executable found for OCI runtime crun: invalid argument
WARN[0000] Error initializing configured OCI runtime crun: no valid executable found for OCI runtime crun: invalid argument
REPOSITORY                   TAG       IMAGE ID       CREATED        SIZE
....

This is fc30, not fc31. I made the warnings go away by hand-editing ~/.config/containers/libpod.conf but am concerned that this is going to come back and haunt us; in particular, regular users will end up doing the same (removing runc from config) and then ending up with nonworking podman when they upgrade to fc31.

[mheon]

This repros as rootless, but not as root. I'm really confused as to why default log level is not the same between the two.

[mheon]

We explicitly set ERROR level logging by default for Podman, unconditionally, unless overridden by CLI.

[mheon]

$ podman info --log-level=error
WARN[0000] cannot find mappings for user mcs: No subuid ranges found for user "mcs" in /etc/subuid 
WARN[0000] using rootless single mapping into the namespace. This might break some images. Check /etc/subuid and /etc/subgid for adding subids 

Well there's our problem. logrus as rootless is ignoring log-level=error. Maybe something about how we exec a new process?

[mheon]

I think it's definitely the re-exec part of rootless.

[edsantiago]

Nice. Fixing this bug may then fix #4012 and get gating tests to pass on rawhide.

[mheon]

@giuseppe Poke - where does rootless re-exec happen? I'm trying to trace the code, but getting lost in the make pause process vs join pause process bit.

[mheon]

Alright, we seem to be passing literal argv into the reexec'd process... So I don't see how we're losing the log level.

[mheon]

Does not seem directly related to reexec... I can get it to happen both inside and outside the rootless user namespace.