Add swap to stats to Summary API and Prometheus endpoints (`/stats/summary` and `/metrics/resource`) #118865

iholder101 · 2023-06-26T10:03:33Z

What type of PR is this?

/kind feature
/sig node
/area kubelet

What this PR does / why we need it:

The Summary API, which is reachable through the stats/summary endpoint, allows to to consume mertics and statistics gathered by Kubelet at the node, volume, pod and container level.

This PR adds current swap usage to the summary API as part of the requirements to graduate swap to Beta1.

In addition, it adds "node_swap_usage_bytes", pod_swap_usage_bytes and container_swap_usage_bytes metrics that would be reachable from /metrics/resource which is also used as a Prometheus endpoint.

Which issue(s) this PR fixes:

Fixes #119424
Fixes #119425

Special notes for your reviewer:

AFAICT, cadvisor is being used to fetch the metric data. If it is not available through cadvisor, it's possible to fallback into gathering CRI data. Unfortunately, it doesn't seem currently possible to do so (here) since memory usage is not part of the CRI-API. In follow-up work, I think it should be added as well, as I don't see a reason to why CRIs wouldn't be able to provide this information.

Does this PR introduce a user-facing change?

Add swap to stats to Summary API and Prometheus endpoints (stats/summary and /metrics/resource).

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

- [KEP]: https://github.com/kubernetes/enhancements/blob/master/keps/sig-node/2400-node-swap/README.md#beta-1

Sample output

In order to test this, I've created a pod named test-pod on an environment with NodeSwap feature gate on and UnlimitedSwap.

The /metrics/resource endpoint looks as follows:

> kubectl get --raw "/api/v1/nodes/<NODE-NAME>/proxy/metrics/resource"
# HELP container_cpu_usage_seconds_total [ALPHA] Cumulative cpu time consumed by the container in core-seconds
# TYPE container_cpu_usage_seconds_total counter
container_cpu_usage_seconds_total{container="c1",namespace="default",pod="test-pod"} 128.476535 1687950863878
container_cpu_usage_seconds_total{container="coredns",namespace="kube-system",pod="coredns-8f5847b64-t9gmr"} 0.915609 1687950855483
# HELP container_memory_working_set_bytes [ALPHA] Current working set of the container in bytes
# TYPE container_memory_working_set_bytes gauge
container_memory_working_set_bytes{container="c1",namespace="default",pod="test-pod"} 3.92847388672e+11 1687950863878
container_memory_working_set_bytes{container="coredns",namespace="kube-system",pod="coredns-8f5847b64-t9gmr"} 1.5310848e+07 1687950855483
# HELP container_start_time_seconds [ALPHA] Start time of the container since unix epoch in seconds
# TYPE container_start_time_seconds gauge
container_start_time_seconds{container="c1",namespace="default",pod="test-pod"} 1.6879504889662333e+09 1687950488966
container_start_time_seconds{container="coredns",namespace="kube-system",pod="coredns-8f5847b64-t9gmr"} 1.6879504537882898e+09 1687950453788
# HELP container_swap_usage_bytes [ALPHA] Current container amount of swap usage in bytes
# TYPE container_swap_usage_bytes gauge
container_swap_usage_bytes{container="c1",namespace="default",pod="test-pod"} 3.4400333824e+10 1687950863878
container_swap_usage_bytes{container="coredns",namespace="kube-system",pod="coredns-8f5847b64-t9gmr"} 0 1687950855483
# HELP node_cpu_usage_seconds_total [ALPHA] Cumulative cpu time consumed by the node in core-seconds
# TYPE node_cpu_usage_seconds_total counter
node_cpu_usage_seconds_total 45770.147028 1687950863599
# HELP node_memory_working_set_bytes [ALPHA] Current working set of the node in bytes
# TYPE node_memory_working_set_bytes gauge
node_memory_working_set_bytes 3.95755573248e+11 1687950863599
# HELP node_swap_usage_bytes [ALPHA] Current node swap usage in bytes
# TYPE node_swap_usage_bytes gauge
node_swap_usage_bytes 1.8446743709127774e+19 1687950863599
# HELP pod_cpu_usage_seconds_total [ALPHA] Cumulative cpu time consumed by the pod in core-seconds
# TYPE pod_cpu_usage_seconds_total counter
pod_cpu_usage_seconds_total{namespace="default",pod="test-pod"} 123.291472 1687950858784
pod_cpu_usage_seconds_total{namespace="kube-system",pod="coredns-8f5847b64-t9gmr"} 5.101812 1687950863144
# HELP pod_memory_working_set_bytes [ALPHA] Current working set of the pod in bytes
# TYPE pod_memory_working_set_bytes gauge
pod_memory_working_set_bytes{namespace="default",pod="test-pod"} 3.92474558464e+11 1687950858784
pod_memory_working_set_bytes{namespace="kube-system",pod="coredns-8f5847b64-t9gmr"} 1.5499264e+07 1687950863144
# HELP pod_swap_usage_bytes [ALPHA] Current pod amount of swap usage in bytes
# TYPE pod_swap_usage_bytes gauge
pod_swap_usage_bytes{namespace="default",pod="test-pod"} 3.4379333632e+10 1687950858784
pod_swap_usage_bytes{namespace="kube-system",pod="coredns-8f5847b64-t9gmr"} 0 1687950863144
# HELP scrape_error [ALPHA] 1 if there was an error while getting container metrics, 0 otherwise
# TYPE scrape_error gauge
scrape_error 0

The /stats/summary endpoint looks as follows (some parts were omitted and replaced by ... for simplicity):

> kubectl get --raw "/api/v1/nodes/localhost/proxy/stats/summary"
{
 "node": {
  "nodeName": "localhost",
  "systemContainers": [
   {
    "name": "kubelet",
    "startTime": "2023-06-28T11:07:22Z",
    "cpu": {
     ...
    },
    "memory": {
     "time": "2023-06-28T11:14:20Z",
     "usageBytes": 5760372736,
     "workingSetBytes": 435998720,
     "rssBytes": 364462080,
     "pageFaults": 178945553,
     "majorPageFaults": 183852
    },
    "swap": {
     "time": "2023-06-28T11:14:20Z",
     "swapUsageBytes": 532729856
    }
   },
   {
    "name": "pods",
    "startTime": "2023-06-25T13:15:58Z",
    "cpu": {
     ...
    },
    "memory": {
     "time": "2023-06-28T11:14:23Z",
     "availableBytes": 11100356608,
     "usageBytes": 392888811520,
     "workingSetBytes": 392850468864,
     "rssBytes": 391990575104,
     "pageFaults": 938848963,
     "majorPageFaults": 7139
    },
    "swap": {
     "time": "2023-06-28T11:14:23Z",
     "swapUsageBytes": 34400399360
    }
   }
  ],
  "startTime": "2023-06-25T13:13:08Z",
  "cpu": {
   "time": "2023-06-28T11:14:23Z",
   "usageNanoCores": 10005001255,
   "usageCoreNanoSeconds": 45770147028000
  },
  "memory": {
   "time": "2023-06-28T11:14:23Z",
   "availableBytes": 8195252224,
   "usageBytes": 400979005440,
   "workingSetBytes": 395755573248,
   "rssBytes": 392447672320,
   "pageFaults": 2055388993,
   "majorPageFaults": 263184
  },
  "network": {
    ...
  },
  "fs": {
   ...
  },
  "runtime": {
   ...
  },
  "rlimit": {
   ...
  },
  "swap": {
   "time": "2023-06-28T11:14:23Z",
   "swapAvailableBytes": 407531442176,
   "swapUsageBytes": 18446743709127774208
  }
 },
 "pods": [
  {
   "podRef": {
    "name": "test-pod",
    "namespace": "default",
    "uid": "85cfce3e-0299-4622-8137-4f414e2f3bd1"
   },
   "startTime": "2023-06-28T11:08:08Z",
   "containers": [
    {
     "name": "c1",
     "startTime": "2023-06-28T11:08:08Z",
     "cpu": {
      ...
     },
     "memory": {
      "time": "2023-06-28T11:14:23Z",
      "usageBytes": 392847446016,
      "workingSetBytes": 392847388672,
      "rssBytes": 391990722560,
      "pageFaults": 241860819,
      "majorPageFaults": 114
     },
     "rootfs": {
      ...
     },
     "logs": {
      ...
     },
     "swap": {
      "time": "2023-06-28T11:14:23Z",
      "swapUsageBytes": 34400333824
     }
    }
   ],
   "cpu": {
    ...
   },
   "memory": {
    "time": "2023-06-28T11:14:18Z",
    "usageBytes": 392474583040,
    "workingSetBytes": 392474558464,
    "rssBytes": 391627411456,
    "pageFaults": 241768635,
    "majorPageFaults": 114
   },
   "volume": [
    ...
   ],
   "ephemeral-storage": {
    ...
   },
   "process_stats": {
    "process_count": 0
   },
   "swap": {
    "time": "2023-06-28T11:14:18Z",
    "swapUsageBytes": 34379333632
   }
  },
  {
   "podRef": {
    "name": "coredns-8f5847b64-t9gmr",
    "namespace": "kube-system",
    "uid": "d0d8b989-ac33-4688-8b33-81613acd640c"
   },
   "startTime": "2023-06-28T11:07:33Z",
   "containers": [
    {
     "name": "coredns",
     "startTime": "2023-06-28T11:07:33Z",
     "cpu": {
      ...
     },
     "memory": {
      "time": "2023-06-28T11:14:15Z",
      "availableBytes": 162947072,
      "usageBytes": 15998976,
      "workingSetBytes": 15310848,
      "rssBytes": 13619200,
      "pageFaults": 6318,
      "majorPageFaults": 9
     },
     "rootfs": {
      ...
     },
     "logs": {
      ...
     },
     "swap": {
      "time": "2023-06-28T11:14:15Z",
      "swapUsageBytes": 0
     }
    }
   ],
   "cpu": {
    ...
   },
   "memory": {
    "time": "2023-06-28T11:14:23Z",
    "availableBytes": 162758656,
    "usageBytes": 16191488,
    "workingSetBytes": 15499264,
    "rssBytes": 13729792,
    "pageFaults": 8491,
    "majorPageFaults": 9
   },
   "volume": [
    ...
   ],
   "ephemeral-storage": {
    ...
   },
   "process_stats": {
    "process_count": 0
   },
   "swap": {
    "time": "2023-06-28T11:14:23Z",
    "swapUsageBytes": 0
   }
  }
 ]
}

k8s-ci-robot · 2023-06-26T10:03:42Z

Hi @iholder101. Thanks for your PR.

I'm waiting for a kubernetes member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

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/test-infra repository.

iholder101 · 2023-06-26T10:06:50Z

/cc @harche @pacoxu

pacoxu · 2023-06-26T10:33:09Z

Should we add it to /metrics/resource/ as well or only?
As https://kubernetes.io/docs/tasks/debug/debug-cluster/resource-metrics-pipeline/ pointed out, metric-server alter to use it now.

Metrics resource endpoint /metrics/resource in version v0.6.0+ or
Summary API endpoint /stats/summary in older versions

iholder101 · 2023-06-26T10:50:09Z

Should we add it to /metrics/resource/ as well or only? As https://kubernetes.io/docs/tasks/debug/debug-cluster/resource-metrics-pipeline/ pointed out, metric-server alter to use it now.

Metrics resource endpoint /metrics/resource in version v0.6.0+ or
Summary API endpoint /stats/summary in older versions

Please correct me if I'm wrong, but IIUC /metrics/resource/ would be populated with the same logic, therefore it's already supported.

You can see that in server.go, these metrics are populated by s.resourceAnalyzer of the ResourceAnalyzer interface. This interface embeds SummaryProvider with Get() and GetCPUAndMemoryStats() methods that eventually use cadvisorInfoToContainerCPUAndMemoryStats(), the function I've implemented support in.

Am I missing something here?

pacoxu · 2023-06-26T11:07:15Z

If so, this would be valid.

/ok-to-test

swatisehgal · 2023-06-27T11:30:33Z

/triage accepted
/priority important-soon
As this is work is being targeted for 1.28 release and is already captured in the SIG Node planning doc.

Signed-off-by: Itamar Holder <iholder@redhat.com>

mrunalp · 2023-07-18T00:00:19Z

/lgtm

k8s-ci-robot · 2023-07-18T00:00:26Z

LGTM label has been added.

Git tree hash: fc5fc1bd2080a44cb900a0bef5a248111991e3fe

k8s-ci-robot added the needs-priority Indicates a PR lacks a `priority/foo` label and requires one. label Jun 26, 2023

k8s-ci-robot requested review from endocrimes and mrunalp June 26, 2023 10:04

iholder101 marked this pull request as ready for review June 26, 2023 10:04

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k8s-ci-robot requested review from andrewsykim and SergeyKanzhelev June 26, 2023 10:05

k8s-ci-robot requested review from harche and pacoxu June 26, 2023 10:06

k8s-ci-robot added ok-to-test Indicates a non-member PR verified by an org member that is safe to test. and removed needs-ok-to-test Indicates a PR that requires an org member to verify it is safe to test. labels Jun 26, 2023

iholder101 force-pushed the kubelet/add-swap-to-summary-stats branch from a00c580 to 4671e33 Compare June 26, 2023 11:23

iholder101 marked this pull request as draft June 27, 2023 11:16

k8s-ci-robot added the do-not-merge/work-in-progress Indicates that a PR should not merge because it is a work in progress. label Jun 27, 2023

iholder101 mentioned this pull request Jun 27, 2023

[Metrics]: Add a node swap metric #118813

Closed

iholder101 added 4 commits July 18, 2023 02:55

Unit tests: CRI swap stats

7d187f9

Signed-off-by: Itamar Holder <iholder@redhat.com>

Add a node swap usage resource metric (/metrics/resource)

1d36842

Signed-off-by: Itamar Holder <iholder@redhat.com>

Unit tests: node swap usage resource metric

e429793

Signed-off-by: Itamar Holder <iholder@redhat.com>

Adjust summary API e2e test

4cb5547

Signed-off-by: Itamar Holder <iholder@redhat.com>

iholder101 force-pushed the kubelet/add-swap-to-summary-stats branch from 8a32f45 to 4cb5547 Compare July 17, 2023 23:56

k8s-ci-robot removed the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Jul 17, 2023

k8s-ci-robot requested review from harche, SergeyKanzhelev and thockin July 17, 2023 23:56

k8s-ci-robot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Jul 17, 2023

k8s-ci-robot assigned mrunalp Jul 18, 2023

k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Jul 18, 2023

k8s-ci-robot merged commit b4d793c into kubernetes:master Jul 18, 2023

k8s-ci-robot added this to the v1.28 milestone Jul 18, 2023

harche mentioned this pull request Jul 18, 2023

Test failure: [sig-node] ResourceMetricsAPI [NodeFeature:ResourceMetrics] when querying /resource/metrics should report resource usage through the resource metrics api #119400

Closed

pacoxu mentioned this pull request Jul 21, 2023

failed to create containerd task: memory.memsw.limit_in_bytes: no such file or directory: unknown containerd/containerd#8855

Closed

iholder101 mentioned this pull request Jul 21, 2023

REQUEST: New membership for iholder101 kubernetes/org#4342

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31 tasks

harche mentioned this pull request Jan 17, 2024

[KEP-2400] - Update KEP with findings from beta2 kubernetes/enhancements#4401

Merged

iholder101 mentioned this pull request Mar 17, 2024

[KEP-2400]: Add swap to kubectl describe node's output #123963

Closed

iholder101 mentioned this pull request Jun 5, 2024

[KEP-2400]: Restrict access to swap for containers in high priority Pods #125277

Merged

jaskaransarkaria mentioned this pull request Jun 5, 2024

Planning upgrade to EKS 1.28 ministryofjustice/cloud-platform#5570

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iholder101 mentioned this pull request Jul 25, 2024

[KEP-2400]: Add a NodeSwapnode condition #125278

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iholder101 mentioned this pull request Dec 24, 2024

Swap stats is not shown as part of the metrics/resource endpoint #129382

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Add swap to stats to Summary API and Prometheus endpoints (`/stats/summary` and `/metrics/resource`) #118865

Add swap to stats to Summary API and Prometheus endpoints (`/stats/summary` and `/metrics/resource`) #118865

iholder101 commented Jun 26, 2023 •

edited

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k8s-ci-robot commented Jun 26, 2023

iholder101 commented Jun 26, 2023

pacoxu commented Jun 26, 2023

iholder101 commented Jun 26, 2023

pacoxu commented Jun 26, 2023

swatisehgal commented Jun 27, 2023

mrunalp commented Jul 18, 2023

k8s-ci-robot commented Jul 18, 2023

Add swap to stats to Summary API and Prometheus endpoints (/stats/summary and /metrics/resource) #118865

Add swap to stats to Summary API and Prometheus endpoints (/stats/summary and /metrics/resource) #118865

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iholder101 commented Jun 26, 2023 • edited Loading

What type of PR is this?

What this PR does / why we need it:

Which issue(s) this PR fixes:

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

Sample output

k8s-ci-robot commented Jun 26, 2023

iholder101 commented Jun 26, 2023

pacoxu commented Jun 26, 2023

iholder101 commented Jun 26, 2023

pacoxu commented Jun 26, 2023

swatisehgal commented Jun 27, 2023

mrunalp commented Jul 18, 2023

k8s-ci-robot commented Jul 18, 2023

Add swap to stats to Summary API and Prometheus endpoints (`/stats/summary` and `/metrics/resource`) #118865

Add swap to stats to Summary API and Prometheus endpoints (`/stats/summary` and `/metrics/resource`) #118865

iholder101 commented Jun 26, 2023 •

edited

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