3. The Heatmaps View

The Heatmaps view gives you a graphic representation of the overall utilization of your cluster using simple color coding.

Each host in the cluster is represented by a block. To see more information on a specific host, hover your mouse over the block you are interested in, and a popup with key host data appears. The color of the blocks represents usage in an appropriate unit based on a selectable set of metrics. If the data necessary to determine state are not all available, the block is marked as having Invalid Data. Changing the default maximum values for the heatmap allows you to fine tune the representation.

Currently the following metrics are supported:

  • Host/Disk Space Used % Uses disk.disk_free and disk.disk_total

  • Host/Memory Used %: Uses memory.mem_free and memory.mem_total

  • HDFS/Bytes Read: Uses dfs.datanode.bytes_read

  • HDFS/Bytes Written: Uses dfs.datanode.bytes_written

  • HDFS/Garbage Collection Time: Uses jvm.gcTimeMillis

  • HDFS/JVM Heap MemoryUsed: Uses jvm.memHeapUsedM

  • MapReduce/Maps Running: Uses mapred.tasktracker.maps_running

  • MapReduce/Reduces Running: Uses mapred.tasktracker.reduces_running

  • MapReduce/Garbage Collection Time: Uses jvm.gcTimeMillis

  • MapReduce/JVM Heap Memory Used: Uses jvm.memHeapUsedM

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