50 lines
1.9 KiB
Markdown
50 lines
1.9 KiB
Markdown
---
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title: Node metrics data
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content_type: reference
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weight: 50
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description: >-
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Mechanisms for accessing metrics at node, volume, pod and container level,
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as seen by the kubelet.
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---
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The [kubelet](/docs/reference/command-line-tools-reference/kubelet/)
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gathers metric statistics at the node, volume, pod and container level,
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and emits this information in the
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[Summary API](https://github.com/kubernetes/kubernetes/blob/7d309e0104fedb57280b261e5677d919cb2a0e2d/staging/src/k8s.io/kubelet/pkg/apis/stats/v1alpha1/types.go).
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You can send a proxied request to the stats summary API via the
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Kubernetes API server.
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Here is an example of a Summary API request for a node named `minikube`:
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```shell
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kubectl get --raw "/api/v1/nodes/minikube/proxy/stats/summary"
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```
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Here is the same API call using `curl`:
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```shell
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# You need to run "kubectl proxy" first
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# Change 8080 to the port that "kubectl proxy" assigns
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curl http://localhost:8080/api/v1/nodes/minikube/proxy/stats/summary
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```
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{{< note >}}
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Beginning with `metrics-server` 0.6.x, `metrics-server` queries the `/metrics/resource`
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kubelet endpoint, and not `/stats/summary`.
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{{< /note >}}
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## Summary metrics API source {#summary-api-source}
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By default, Kubernetes fetches node summary metrics data using an embedded
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[cAdvisor](https://github.com/google/cadvisor) that runs within the kubelet. If you
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enable the `PodAndContainerStatsFromCRI` [feature gate](/docs/reference/command-line-tools-reference/feature-gates/)
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in your cluster, and you use a container runtime that supports statistics access via
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{{< glossary_tooltip term_id="cri" text="Container Runtime Interface">}} (CRI), then
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the kubelet [fetches Pod- and container-level metric data using CRI](/docs/reference/instrumentation/cri-pod-container-metrics), and not via cAdvisor.
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## {{% heading "whatsnext" %}}
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The task pages for [Troubleshooting Clusters](/docs/tasks/debug/debug-cluster/) discuss
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how to use a metrics pipeline that rely on these data.
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