This is the MR side of
If you start a pseudo distributed yarn using "start-yarn.sh" you need to specify exports for HADOOP_COMMON_HOME, HADOOP_HDFS_HOME, YARN_HOME, YARN_CONF_DIR, and HADOOP_MAPRED_HOME in hadoop-env.sh (or elsewhere), otherwise the spawned node manager will be missing
these in it's environment. This is due to start-yarn using yarn-daemons. With this fix it's possible to start yarn (etc...) with only HADOOP_CONF_DIR specified in the environment. Took some time to track down this failure, so seems worthwhile to fix.