Hadoop configuration file description

1. dfs. hosts records the list of machines that will be added to the cluster as datanode
2. mapred. hosts records the list of machines that will be added to the cluster as tasktracker
3. dfs. Hosts. Exclude mapred. Hosts. Exclude contains the list of machines to be removed.
4. The master record the list of machines that run the auxiliary namenode.
5. Slave records the list of machines running datanode and tasktracker
6. hadoop-env.sh record the environment variables used by the script to run hadoop
7. core-site.xml of hadoop core configuration items, such as HDFS and mapreduce commonly used I/O settings, etc.
8. hdfs-site.xml hadoop daemon configuration items, including namenode, auxiliary namenode and datanode
9. configuration items for the mapred-site.xml mapreduce daemon, including jobtracker and tasktracker
10. hadoop-metrics.properties controls how metrics releases attributes on hadoop
11. attributes of the log4j. properties System Log File, namenode audit log, and tasktracker sub-process task log