Kubelet & cAdvisor

Overview

Kubelet is a service that runs on each worker node in a Kubernetes cluster and is resposible for managing the Pods and containers on a machine. cAdvisor is a container resource usage and performance analysis tool, open sourced by Google. For monitoring Kubernetes with Prometheus we care about Kubelet and cAdvisor becuase we can scrape metrics from these services regarding container resource usage.

Deployment

We do not need to deploy a Prometheus Exporter to scrape metrics from Kublet and cAdvisor as they expose metrics endpoints out the box, therefore we only need to configure Prometheus to start scraping metrics using a ServiceMonitor.

Create a file called kubelet.yaml and add the following:

apiVersion: monitoring.coreos.com/v1
kind: ServiceMonitor
metadata:
  labels:
    app: kubelet
    serviceMonitorSelector: prometheus
  name: kubelet
  namespace: prometheus
spec:
  endpoints:
  - bearerTokenFile: /var/run/secrets/kubernetes.io/serviceaccount/token
    honorLabels: true
    interval: 30s
    port: http-metrics
    scheme: http
    tlsConfig:
      insecureSkipVerify: true
  - bearerTokenFile: /var/run/secrets/kubernetes.io/serviceaccount/token
    honorLabels: true
    interval: 30s
    path: /metrics/cadvisor
    port: http-metrics
    scheme: http
    tlsConfig:
      insecureSkipVerify: true
  jobLabel: kubelet
  namespaceSelector:
    matchNames: