1) dfs.namenode.hosts / dfs.namenode.hosts.exclude.
>> I did not seen above two properties in code...I feel,This should be dfs.hosts/dfs.hosts.exclude
2) conf /hadoop-env.sh and conf /yarn-env.sh
>> Most of the places written as conf dir,,but currently conf dir will not present in hadoop distribution.
It's better to give HADOOP_CONF_DIR /hadoop-env.sh or HADOOP_HOME/etc/hadoop /hadoop-env.sh