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Prometheus exporter to expose ephemeral storage usage stats from Kubelets

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kubelet-stats-exporter

This is a Prometheus exporter to expose a Pods ephemeral storage usage stats from the Kubelets

The Kubernetes Kubelet has some metrics on ephemeral storage usage that are not currently exposed elsewhere. It may be useful to present these in a format that can be collected by Prometheus. Note the kubelet of Docker Desktop does not expose these metrics, so it is not a useful environment for testing.

It accesses the Kubelet on each node, via the Kubernetes API proxy. Authentication is done to the kubelet using a service account that is configured in k8s-resources/ns-rbac.yaml.

Background reading:

Although these metrics are exposed by the kubelet API, they are not exposed on the kubelets /metrics endpoint, nor are they currently collected or exported with kube-state-metrics. Some issues with similar requests can be seen here:

kubernetes/kube-state-metrics#1046 (kubernetes/kube-state-metrics#1046 (comment))

kubernetes/kubernetes#69507

Requirements

The following pip libraries are required:

  • flask
  • kubernetes
  • prometheus_client
  • python-json-logger
  • requests

Configuration

The following environment variables are useful to configure the application:

Name Type Default Description
EXPORTER_PORT int 9118 Port exposing prometheus metrics
JSON_LOGGER bool true Application logs on JSON Format for easier centralization using log shippers such as FluentBit
LOG_LEVEL str INFO Logging Level. Werkzeug requests only logged on DEBUG level for log centralization costs saving purposes
KUBERNETES_API_TIMEOUT int 5 Kubernetes API Scrape timeout. Make sure KUBERNETES_API_TIMEOUT is smaller than Prometheus Scrape timeout.

Exporter Endpoints

  • /health - Application Status for Kubernetes readiness & liveness probes check.
  • /metrics - Prometheus metrics endpoint.

Deployment

Kubernetes Manifests

Apply Kubernetes resources: kubectl apply -f ./k8s-resources

If you're using the PrometheusOperator, and want to configure a ServiceMonitor, apply the extra/servicemonitor.yaml file.

Example dashboards for Grafana can be seen in the extra folder.

Helm Chart

You could use kubelet-stats-exporter chart to deploy kubelet-stats-exporter using helm.

helm repo add sequra-community https://sequra.github.io/helm-charts
helm repo update
helm install [RELEASE_NAME] sequra-community/prometheus-kubelet-stats-exporter

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