Recommendations on what to monitor on clusters.

Cloudera recommends that administrators continuously monitor the following on a cluster:
Replication Status
Monitor replication status using Cloudera Manager Health Tests. Cloudera Manager automatically and continuously monitors both the OfflineLogDirectoryCount and OfflineReplicaCount metrics. Alters are raised when failures are detected.
Disk Capacity
Monitor free space on mounted disks and open file descriptors. Reassign partitions or move log files around if necessary. For more information, see the kafka-reassign-partitions tool description.