Add pvc name and namespace to kubernetes volume metricset

[morganchristiansson]

I am trying to monitor PVC space utilization. There's currently no way to easily distinguish between a emptyDir/configMap from a pvc volume from the metrics reported.

This PR added PVCRef with namespace and name of the PVC which would easily allow me to filter out volumes aren't relevant. kubernetes/kubernetes#51448

It would be grand if we can add pvc name and namespace to the volume metricset.

Thank you

[morganchristiansson]

Something like this matches well with defined metricset style and how metricbeat munges kubelet API json nicely

    "kubernetes": {
        "volume": {
            "pvc": {
                "name": "pvcname",
                "namespace": "pvcnamespace"
            }
        }
    }
}

Full metricset: https://www.elastic.co/guide/en/beats/metricbeat/master/metricbeat-metricset-kubernetes-volume.html

[botelastic]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.