I have container_fs_usage_bytes with prometheus to monitor container root fs, but it seems that there is no metrics for other volumes in cAdvisor.
I confirmed that Kubernetes 1.8 expose metrics for prometheus.
kubelet_volume_stats_available_byteskubelet_volume_stats_capacity_byteskubelet_volume_stats_inodeskubelet_volume_stats_inodes_freekubelet_volume_stats_inodes_usedkubelet_volume_stats_used_bytesMetrics for volumes are available via the kubelet summary API (/stats/summary). However, each volume plugin has to implement their own metrics. As of Kubernetes 1.7, the current volume plugins that have implemented metrics include: emptydir, secrets, gce pd, aws ebs, azure file, flocker, and portworx