Time for action – killing a TaskTracker process

We've abused HDFS and its DataNode enough; now let's see what damage we can do to MapReduce by killing some TaskTracker processes.

Though there is an mradmin command, it does not give the sort of status reports we are used to with HDFS. So we'll use the MapReduce web UI (located by default on port 50070 on the JobTracker host) to monitor the MapReduce cluster health.

Perform the following steps:

  1. Ensure everything is running via the start-all.sh script then point your browser at the MapReduce web UI. The page should look like the following screenshot:
    Time for action – killing a TaskTracker process
  2. Start a long-running MapReduce job; the example pi estimator ...

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