Alert rule: CephNodeRootFilesystemFull

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Root volume (OSD and MON store) is dangerously full. You should increase the space available to the node. The default location for the store sits under /var/lib/rook/ as a hostPath volume.

Steps for debugging

Check node low on disk space

$ ceph_cluster_ns=syn-rook-ceph-cluster
$ ceph_mon_name=a (1)
$ kubectl -n ${ceph_cluster_ns} get deploy -lapp=rook-ceph-mon,mon=${ceph_mon_name}  -ojson | jq '.items[].spec.template.spec.nodeSelector'
  "": "storage-XXXX" (2)
1 The name of the monitor that’s alerting.
2 The node that the monitor is running on.

Increase the size of the node’s disk

Increase the size of the node’s disk according to your cloud provider’s documentation.