title: How do I get a pod's (milli)core CPU usage with Prometheus in Kubernetes?
body: <p>I run a <code>v1.9.2</code> custom setup of Kubernetes and scrape various metrics with Prometheus <code>v2.1.0</code>. Among others, I scrape the <code>kubelet</code> and <code>cAdvisor</code> metrics.</p>
  
  <p>I want to answer the question: "<em>How much of the CPU resources defined by <code>requests</code> and <code>limits</code> in my deployment are actually used by a pod (and its containers) in terms of (milli)cores?</em>"</p>
  
  <p>There are a lot of scraped metrics available, but nothing like that. Maybe it could be calculated by the CPU usage time in seconds, but I don't know how.</p>
  
  <p>I was considering it's not possible - until a friend told me she runs Heapster in her cluster which has a graph in the built-in Grafana that tells <em>exactly</em> that: It shows the indivual CPU usage of a pod and its containers in (milli)cores.</p>
  
  <p>Since Heapster also uses <code>kubelet</code> and <code>cAdvisor</code> metrics, I wonder: how can I calculate the same? The metric in InfluxDB is named <code>cpu/usage_rate</code> but even with Heapster's code, I couldn't figure out how they calculate it.</p>
  
  <p>Any help is appreciated, thanks!</p>