On all of the nodes
in your Hadoop cluster that have a yarn-site.xml file, two main configuration
properties specify the application CLASSPATH: yarn.application.classpath
and mapreduce.application.classpath. If you do not specify the YARN
application CLASSPATH, MapR takes the default CLASSPATH. However,
if you specify the MapReduce application CLASSPATH, the YARN application
CLASSPATH is ignored. The SAS Embedded Process for Hadoop requires
both the MapReduce application CLASSPATH and the YARN application
CLASSPATH.
To ensure the existence
of the YARN application CLASSPATH, you must manually add the YARN
application CLASSPATH to the yarn-site.xml file. Without the manual
definition in the configuration file, the MapReduce application master
fails to start a container.
The default YARN application
CLASSPATH for Linux is:
$HADOOP_CONF_DIR,
$HADOOP_COMMON_HOME/share/hadoop/common/*,
$HADOOP_COMMON_HOME/share/hadoop/common/lib/*,
$HADOOP_HDFS_HOME/share/hadoop/hdfs/*,
$HADOOP_HDFS_HOME/share/hadoop/hdfs/lib/*,
$HADOOP_YARN_HOME/share/hadoop/yarn/*,
$HADOOP_YARN_HOME/share/hadoop/yarn/lib/*
The default YARN application
CLASSPATH for Windows is:
%HADOOP_CONF_DIR%,
%HADOOP_COMMON_HOME%/share/hadoop/common/*,
%HADOOP_COMMON_HOME%/share/hadoop/common/lib/*,
%HADOOP_HDFS_HOME%/share/hadoop/hdfs/*,
%HADOOP_HDFS_HOME%/share/hadoop/hdfs/lib/*,
%HADOOP_YARN_HOME%/share/hadoop/yarn/*,
%HADOOP_YARN_HOME%/share/hadoop/yarn/lib/*
Note: On MapR, the YARN application
CLASSPATH does not resolve the symbols or variables specified in the
paths ($HADOOP_HDFS_HOME, and so on).
Tip
Anytime you make a change
to the cluster, remember to restart the node managers to pick up the
change.