title: Monitoring Kubernetes persistent volumes usage with Prometheus
body: <p>I have a K8s 1.7 cluster using <strong>vSphere</strong> as persistent storage provider. I have also deployed <strong>Prometheus</strong>, <strong>node_exporter</strong> and <strong>kube-state-metrics</strong>.<p>
  I'm trying to find a way to monitor a persistent volume's usage using <strong>Prometheus</strong>. I have added custom labels to some PVs, eg. <code>app=rabbitmq-0</code>, etc. </p>
  
  <p>How can I combine <code>kube_persistentvolume_labels</code> with <code>node_filesystem_size</code> metrics so that I can query PV usage using my custom label?</p>
  
  <p>PS.<br>
  I know that K8s 1.8 directly exposes these metrics from kubelet as mentioned in <a href="https://stackoverflow.com/questions/44718268/how-to-monitor-disk-usage-of-kubernetes-persistent-volumes">How to monitor disk usage of kubernetes persistent volumes?</a> but currently a cluster upgrade is not an option.</p>