podman network create/rm: please ignore ENOENT

[edsantiago]

There's a race condition between the time podman reads its CNI directory and the time it tries to read conflist files. Trivial reproducer (requires two shells):

! window 1
$ while :;do bin/podman network create aaa;bin/podman network rm -f aaa;done

! window 2
$ while :;do bin/podman network create bbb;bin/podman network rm -f bbb;done

Within less than ten seconds, one or the other will spit out:

ERRO[0000] Error loading CNI config list file /home/esm/.config/cni/net.d/xxx.conflist: error reading /home/esm/.config/cni/net.d/xxx.conflist: open /home/esm/.config/cni/net.d/xxx.conflist: no such file or directory

...where xxx is the name of the other window (e.g. you will see "bbb" in the aaa window and vice-versa).

(Note: even though it says ERRO, it's not an error and does not cause a nonzero exit status).

This is really annoying to me when looking at integration-test logs, because they all show up in bright scary orange that makes me think there's an error (and, in some cases, hides real errors because of the cry-wolf thing).

To normal-people users, this is probably kind of alarming, and would presumably cause them to waste an indeterminate amount of time looking into it.

Easy/obvious solution is to just ignore ENOENT, ¿que no?

[edsantiago]

Oops, forgot to xref #9041

[Luap99]

The only place where this error is shown is in ocicni and I already fixed it to make it ignore enoent, at least I thought it was fixed with cri-o/ocicni#85.
https://github.com/cri-o/ocicni/blob/5ce5cee5666d097f0a18341868b87eb8c016480d/pkg/ocicni/ocicni.go#L290-L296
Maybe !os.IsNotExist(err) does not work correctly in this case.

[edsantiago]

@Luap99 maybe my setup doesn't have that vendored in? Can you reproduce on your system?

[Luap99]

It is vendored in. I just checked the code. CNI does not return a warped error. It uses fmt.Errorf("error reading %s: %s", filename, err). Therefore we cannot check the root cause of this error correctly. I think we have to use string comparison to catch this.

[rhatdan]

Yes this output looks like it is a logrus.Error.

[Luap99]

Upstream PR containernetworking/cni#850 to fix this is merged. When they release CNI v1.0.0 we can vendor this in (hopefully soon).

[edsantiago]

Just a quick comment to reset the nagbot. This is still happening often:

Podman network [It] podman network prune

• fedora-33 : int podman fedora-33 root container
  • PR skip flaking auto-update test #11176
    • 08-10 05:54
• fedora-33 : int podman fedora-33 root host
  • PR skip flaking auto-update test #11176
    • 08-10 05:55
• fedora-33 : int podman fedora-33 rootless host
  • PR skip flaking auto-update test #11176
    • 08-10 06:00
• fedora-34 : int podman fedora-34 root container
  • PR skip flaking auto-update test #11176
    • 08-10 05:57
• fedora-34 : int podman fedora-34 root host
  • PR skip flaking auto-update test #11176
    • 08-10 05:58
  • PR auto-update: simple rollback #11074
    • 08-05 10:12

[edsantiago]

Podman network [It] podman network prune

• fedora-33 : int podman fedora-33 root container
  • PR cgroup-info: check if user.slice is valid before accessing value #11463
    • 09-06 16:16
  • PR Shell completion for --format with anonymous fields #11337
    • 08-27 05:37
  • PR profiling: higher memory sampling rate #11308
    • 08-23 11:07
  • PR volumes: Add support for volume import which allows importing contents of external tarballs into podman volumes. #11307
    • 08-26 05:28
  • PR teardown play kube #11298
    • 08-26 10:29
    • 08-25 18:11
• fedora-34 : int remote fedora-34 root host [remote]
  • PR podman upgrade tests for networking #11485
    • 09-09 05:19
• ubuntu-2010 : int podman ubuntu-2010 rootless host
  • PR Qemu TCG Accel fallback for Apple Silicon. Iss #10577 #11451
    • 09-05 13:16
  • PR Make secret env var available to exec session #11376
    • 08-31 14:41
  • PR Globally replace http:// with https:// #11333
    • 08-27 07:03
  • PR runtime: Warn if XDG_RUNTIME_DIR is set but is not writable. #11327
    • 08-30 07:59
• ubuntu-2104 : int podman ubuntu-2104 root host
  • PR network create: add warning for deprecated macvlan flag #11402
    • 09-07 05:10
  • PR podman inspect show exposed ports #11314
    • 08-24 10:34

[Luap99]

CNI version 1.0.0 is available, I can start updating when #11322 is merged.