FindPidByPodContainer unreliable

[michaelgugino]

kubectl-trace/pkg/procfs/procfs.go

Line 59 in 7fd3007

needle := path.Join(podUID, containerID)

This code makes too many assumptions about what the file paths will look like.

Actual mount results on my cluster look like /kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod30cea2cf_1b80_4807_abad_d81453e199c5.slice/crio-a8077b08a56c0c6e33d6716557d882ac940cb09475c50372e22e84c40d0733f2.scope

Additionally, the following agruments get passed to the job container
--pod-uid=30cea2cf-1b80-4807-abad-d81453e199c5 --container-id=cri-o://a8077b08a56c0c6e33d6716557d882ac940cb09475c50372e22e84c40d0733f2

We need to also trim the cri-o:// prefix. The pod UID seems to replace - with _ so that is another issue.

This project works for me: https://github.com/yahoo/kubectl-flame/blob/master/agent/utils/process.go#L35

[dalehamel]

Hi there, we've never tested with cri-o before so thanks for flagging this. Thanks also for linking some more generic code.

[DrAuYueng]

@dalehamel If containerd is used as the CRI runtime, the mount info looks like:

/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod40934a46_d409_4f4a_bb8b_1ec0b0436320.slice/cri-containerd-afc114c69e71f18166abd63715398d7daa763c69a6454f71157272ab0bdca783.scope

The generic code would be better like this:

if strings.Contains(root, podUID) && strings.Contains(root, containerID) {
					return &dname, nil
				}

[DrAuYueng]

@dalehamel I submitted a PR(#207 ) to fix this, can you take a look?