Setting HADOOP_MAPRED_HOME

For each user who will be submitting MapReduce jobs using MapReduce v2 (YARN), or running Pig, Hive, or Sqoop in a YARN installation, make sure that the HADOOP_MAPRED_HOME environment variable is set correctly, as follows:
```
$ export HADOOP_MAPRED_HOME=/usr/lib/hadoop-mapreduce
```
For each user who will be submitting MapReduce jobs using MapReduce v1 (MRv1), or running Pig, Hive, or Sqoop in an MRv1 installation, set the HADOOP_MAPRED_HOME environment variable as follows:
```
$ export HADOOP_MAPRED_HOME=/usr/lib/hadoop-0.20-mapreduce
```