4. Start MapReduce JobHistory Server

Change permissions on the container-executor file.
```
chown -R root:hadoop /usr/lib/hadoop-yarn/bin/container-executor
chmod -R 6050 /usr/lib/hadoop-yarn/bin/container-executor
```
Note
If these permissions are not set, the healthcheck script will return an errror stating that the datanode is UNHEALTHY.

	Note
If these permissions are not set, the healthcheck script will return an errror stating that the datanode is `UNHEALTHY`.

Execute these commands from the JobHistory server to set up directories on HDFS :

su $HDFS_USER
hadoop fs -mkdir -p /mr-history/tmp
hadoop fs -chmod -R 1777 /mr-history/tmp
hadoop fs -mkdir -p /mr-history/done
hadoop fs -chmod -R 1777 /mr-history/done
hadoop fs -chown -R $MAPRED_USER:$HDFS_USER /mr-history

hadoop fs -mkdir -p /app-logs
hadoop fs -chmod -R 1777 /app-logs 
hadoop fs -chown yarn /app-logs

Execute these commands from the JobHistory server:

<login as $MAPRED_USER>
export HADOOP_LIBEXEC_DIR=/usr/lib/hadoop/libexec/
/usr/lib/hadoop-mapreduce/sbin/mr-jobhistory-daemon.sh --config $HADOOP_CONF_DIR start historyserver

where:

$HDFS_USER is the user owning the HDFS services. For example, hdfs.
$MAPRED_USER is the user owning the MapRed services. For example, mapred.
$HADOOP_CONF_DIR is the directory for storing the Hadoop configuration files. For example, /etc/hadoop/conf.

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