pod.status.containerStatuses displayed image name incorrectly when image has multiple tags on the node

[diannaowa]

For more detail: pod.status.containerStatuses displayed image name incorrectly when image has multiple tags on the node

[afbjorklund]

This behaviour is defined by CRI, and seems to be done the same way in containerd:

                repoTags, repoDigests := parseImageReferences(image.References)
                if len(repoTags) > 0 {
                        // Based on current behavior of dockershim, this field should be
                        // image tag.
                        spec = &runtime.ImageSpec{Image: repoTags[0]}
                }
                if len(repoDigests) > 0 {
                        // Based on the CRI definition, this field will be consumed by user.
                        imageRef = repoDigests[0]
                }

Maybe the sort order can be tweaked, but otherwise it needs to be discussed in API ?

Something for SIG Node, https://github.com/kubernetes/community/tree/master/sig-node

[diannaowa]

Thank you for your prompt reply。@afbjorklund
In kubelet, It starts the container through the following steps:
// * pull the image
// * create the container
// * start the container
// * run the post start lifecycle hooks (if applicable)

func (m *kubeGenericRuntimeManager) startContainer(ctx context.Context, podSandboxID string, podSandboxConfig *runtimeapi.PodSandboxConfig, spec *startSpec, pod *v1.Pod, podStatus *kubecontainer.PodStatus, pullSecrets []v1.Secret, podIP string, podIPs []string) (string, error) {
        // Step 1: pull the image.
	imageRef, msg, err := m.imagePuller.EnsureImageExists(ctx, pod, container, pullSecrets, podSandboxConfig)
        ......
        containerConfig, cleanupAction, err := m.generateContainerConfig(ctx, container, pod, restartCount, podIP, imageRef, podIPs, target)
       ......
       // Step 2: create the container.
       ......
       containerID, err := m.runtimeService.CreateContainer(ctx, podSandboxID, containerConfig, podSandboxConfig)
       ......
       // Step 3: start the container.
	err = m.runtimeService.StartContainer(ctx, containerID)
        .....
}

I have a workaround with this issue: Code
This method also works for containerd.
But,I didn't do a compatibility test.
Maybe, this is not expected behavior of CRI.

[evol262]

I'm not convinced that commenting it out entirely is a great workaround, and a 4 year old k8s issue which has more or less identical behavior across CRIs is something we should be hesitant to change. If there were going to be one, sorting ir.ImageTags and then taking the first entry is far preferable.

What are the actual impacts of this, as a reason to resurrect a 4 year old issue?