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Parse container id #207

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Parse container id #207

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9 changes: 2 additions & 7 deletions pkg/procfs/procfs.go
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Original file line number Diff line number Diff line change
Expand Up @@ -51,13 +51,8 @@ func FindPidByPodContainer(podUID, containerID string) (string, error) {
// See https://github.com/kubernetes/kubernetes/blob/2f3a4ec9cb96e8e2414834991d63c59988c3c866/pkg/kubelet/cm/cgroup_manager_linux.go#L81-L85
// Note that these identifiers are currently specific to systemd, however, this mounting approach is what allows us to find the containerized
// process.
//
// EG: /kubepods/burstable/pod31dd0274-bb43-4975-bdbc-7e10047a23f8/851c75dad6ad8ce6a5d9b9129a4eb1645f7c6e5ba8406b12d50377b665737072
// /kubepods/burstable/pod{POD_ID}/{CONTAINER_ID}
//
// This "needle" that we look for in the mountinfo haystack should match one and only one container.
needle := path.Join(podUID, containerID)
if strings.Contains(root, needle) {
// EG: /kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod40934a46_d409_4f4a_bb8b_1ec0b0436320.slice/cri-containerd-afc114c69e71f18166abd63715398d7daa763c69a6454f71157272ab0bdca783.scope
if strings.Contains(root, podUID) && strings.Contains(root, containerID) {
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@cakemanny cakemanny Jun 9, 2024 •
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Which setup have you tested this with?
I also found that I needed to fix this when working on my PR: https://github.com/iovisor/kubectl-trace/pull/205/files#diff-3fc753f2ae105df1b499d656901818c3aae006a40a0d807d4871520a19d612a5

I found podUID contained -s in place of _s in the cgroup name.
i.e. in your example, I'd expect podUID to be "40934a46-d409-4f4a-bb8b-1ec0b0436320".
It looks like that was also mentioned in the description of #174 . (I was using kind v0.19.x on an ubuntu 22.04 VM, not sure the host matters though)

You could also feel inspired to add a unit test like I did..., but I'm not from the iovisor group, just a fellow attempting contributor.

return dname, nil
}
}
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9 changes: 7 additions & 2 deletions pkg/tracejob/selected_target.go
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Expand Up @@ -277,8 +277,13 @@ func resolvePodToTarget(podClient corev1.PodInterface, resourceID, container, ta

for _, s := range pod.Status.ContainerStatuses {
if s.Name == targetContainer {
containerID := strings.TrimPrefix(s.ContainerID, "docker://")
containerID = strings.TrimPrefix(containerID, "containerd://")
// Trim the quotes and split the type and ID.
// See https://github.com/kubernetes/kubernetes/blob/ec93d3b71a6634659b59bf435959f4befafe3796/pkg/kubelet/container/runtime.go#L234
parts := strings.Split(strings.Trim(s.ContainerID, "\""), "://")
if len(parts) != 2 {
return fmt.Errorf("invalid container ID: %q", s.ContainerID)
}
containerID := parts[1]
target.ContainerID = containerID
break
}
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