Used ephemeral storage within kubectl top pod command

[3deep5me]

What would you like to be added:
It would be great to get also the current ephemeral storage usage with kubectl top pods command.

Why is this needed:
This would give useres/me the option to quickly get an estimate for setting requests-and-limits-for-local-ephemeral-storage .

[k8s-ci-robot]

This issue is currently awaiting triage.

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[googs1025]

/cc

[Ritikaa96]

This is a good addition for those who has use case. I'd like to work on it if it the triage is accpeted.

[Ritikaa96]

@mpuckett159 can confirm this is something that we can add in the code.

[3deep5me]

I would help with the documentation.

[Ritikaa96]

sure, Let's first wait for the opinion on accepting the triage.

[googs1025]

I'm not sure if I understand it correctly, but does kubectl top pods fetch usage metrics for ephemeral storage? I tried it and it doesn't seem to.

apiVersion: v1
kind: Pod
metadata:
  name: example-pod-with-ephemeral-storage
spec:
  containers:
  - name: example-container
    image: nginx
    resources:
      requests:
        ephemeral-storage: "500Mi"  
      limits:
        ephemeral-storage: "1Gi"    
    volumeMounts:
    - name: ephemeral-storage-volume
      mountPath: /tmp               
  volumes:
  - name: ephemeral-storage-volume
    emptyDir: {}                   

root@VM-0-3-ubuntu:/home/ubuntu# curl localhost:8181/apis/metrics.k8s.io/v1beta1/namespaces/default/pods/example-pod-with-ephemeral-storage
{
  "kind": "PodMetrics",
  "apiVersion": "metrics.k8s.io/v1beta1",
  "metadata": {
    "name": "example-pod-with-ephemeral-storage",
    "namespace": "default",
    "creationTimestamp": "2025-01-09T13:46:04Z"
  },
  "timestamp": "2025-01-09T13:45:39Z",
  "window": "17.913s",
  "containers": [
    {
      "name": "example-container",
      "usage": {
        "cpu": "0",
        "memory": "4620Ki"
      }
    }
  ]
}root@VM-0-3-ubuntu:/home/ubuntu# kubectl top pods
NAME                                 CPU(cores)   MEMORY(bytes)
example-pod-with-ephemeral-storage   0m           4Mi
root@VM-0-3-ubuntu:/home/ubuntu# kubectl top pods
NAME                                 CPU(cores)   MEMORY(bytes)
example-pod-with-ephemeral-storage   0m           4Mi

[3deep5me]

No, it does not, right now the metric is available by proxying the kubelet stats.
kubectl get --raw "/api/v1/nodes/(your-node-name)/proxy/stats/summary"
How can I determine the current ephemeral-storage usage of a running Kubernetes pod?
This could maybe (?) help but is open since a while: kubernetes/kubernetes#69507

[googs1025]

So currently the metrics server does not support ephemeral storage. I think it is not a good time to support this feature.

[ardaguclu]

We'll discuss this next biweekly meeting.

[Ritikaa96]

Is there any update on this after the biweekly meeting? I checked the notes and didnt find any mention of this one. It will nice to get more community opinion on this .

[ardaguclu]

This will be handled in kubernetes/enhancements#5106
/close

[k8s-ci-robot]

@ardaguclu: Closing this issue.

In response to this:

This will be handled in kubernetes/enhancements#5106
/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[3deep5me]

Hi @ardaguclu, just a question. As far as I understood, kubernetes/enhancements#5106 is about PVC usage, but not about ephemeral storage usage like in an EmptyDir or Pod filesystem. (local node storage) Is that correct?
I could not find the term “ephemeral” in the KEP.

[ardaguclu]

Actually you are right. I should reopen it.

On the other hand, if you have a look at discussions in there, for PVC usage there are already built-in metrics that will be wired from metrics server to kubectl. For ephemeral storage part, I'm not sure if it exists or not. Therefore, I don't think in foreseeable future, we can add this functionality.

[mpuckett159]

/close
First the KEP needs to be implemented before we can decide on adding this because the functionality is not available yet. Once they are supported we can reopen this.

[k8s-ci-robot]

@mpuckett159: Closing this issue.

In response to this:

/close
First the KEP needs to be implemented before we can decide on adding this because the functionality is not available yet. Once they are supported we can reopen this.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.