title: Core pipeline vs Service pipeline. What is better for Kubernetes monitoring?
body: <p>I am using both core pipeline and service pipeline for monitoring Kubernetes cluster resources for testing purposes. However I noticed that there is a difference between the metrics exposed by the 2 pipelines. The core pipeline metrics which were exposed by the metrics server had relatively low values compared to the metrics exposed by the Prometheus. Also there was a similar incident which I noticed before when using node exporter, where the metrics server displayed lower values than the real-time values but the node exporter had much more accurate values.</p>
  <p><a href="https://levelup.gitconnected.com/kubernetes-monitoring-101-core-pipeline-services-pipeline-a34cd4cc9627" rel="nofollow noreferrer">Core pipeline vs Service pipeline</a>
  <a href="https://github.com/kubernetes-sigs/metrics-server/blob/master/FAQ.md" rel="nofollow noreferrer">Metrics-sever calculations</a></p>
  <p>I referred to those 2 documents and some others and did not found any reasons as to why this would happen.</p>
  <ol>
  <li>Does this means that the metrics-server is not reliable ?</li>
  <li>What is the better method for monitoring ? Core pipeline or Service pipeline ?</li>
  </ol>