Special case memory-swap=-1

[rhatdan]

We document that memory-swap==-1 means unlimited, but currently we
won't allow the user to specify the -1 value.

Fixes: #5091

Signed-off-by: Daniel J Walsh dwalsh@redhat.com

[rhatdan]

@s-winter does this fix your problem?

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[s-winter]

@s-winter does this fix your problem?

Thank you for looking into the issue. Unfortunately, I cannot tell if your change fixed my problem or not. I just tried running podman built from your fork of libpod and it fails. I tried merging containers/libpod master and it fails. I spent around an hour googling for the error messages, applying fixes and workarounds here and there and it still fails. I will look into this again when I find more time.

[giuseppe]

Thank you for looking into the issue. Unfortunately, I cannot tell if your change fixed my problem or not. I just tried running podman built from your fork of libpod and it fails. I tried merging containers/libpod master and it fails. I spent around an hour googling for the error messages, applying fixes and workarounds here and there and it still fails. I will look into this again when I find more time.

can you please share the error message? It might be related to crun and how the memory-swap is mapped to cgroups v2, as it works differently from cgroup v1.

Done some work recently in this area: containers/crun#226

[s-winter]

can you please share the error message? It might be related to crun and how the memory-swap is mapped to cgroups v2, as it works differently from cgroup v1.

Invoking podman run -it --rm --memory=500m --memory-swap=-1 docker.io/library/ubuntu I get

Error: invalid configuration, cannot specify resource limits without cgroups v2 and --cgroup-manager=systemd

When I add --cgroup-manager=systemd to my command line I get

ERRO[0000] could not find slirp4netns, the network namespace won't be configured: exec: "slirp4netns": executable file not found in $PATH 
Error: sd-bus add match: Operation not permitted: OCI runtime permission denied error

Adding --net host mutes the error for now and I get

Error: sd-bus add match: Operation not permitted: OCI runtime permission denied error

[giuseppe]

When I add --cgroup-manager=systemd to my command line I get

looks like there is no systemd user session that you can use.

How has the rootless user logged in? Through sudo?

You need to make sure there is a systemd user session, you either need to login through ssh/desktop so that the pam session is created, or you need to use loginctl enable-linger $UID

[rhatdan]

@mheon @giuseppe @baude @TomSweeneyRedHat @QiWang19 PTAL
This at least gets us closer to the solution.

[giuseppe]

LGTM

Tested locally:

$ podman run --rm --memory=500m --memory-swap=-1 fedora cat /sys/fs/cgroup/memory.swap.max
max

[baude]

/lgtm

[s-winter]

looks like there is no systemd user session that you can use.

How has the rootless user logged in? Through sudo?

Direct login via ssh.

You need to make sure there is a systemd user session, you either need to login through ssh/desktop so that the pam session is created, or you need to use loginctl enable-linger $UID

As I wrote I directly log in via ssh. I also tried loginctl enable-linger $UID, but that does not change anything about the error.

I recall that I had the same issue when I was playing with podman earlier, around mid November. I do not recall what I did to resolve it back then or if I resolved it at all. But I was very happy that everything was running out of the box and without problems when I ran version 1.7.0 from the installed Ubuntu package this week. I am surprised that I'm now facing the issue again when switching to a build from libpod's master branch to test the fix proposed by rhatdan.