After the hadoop cluster is started, the datanode node does not start properly.

After the hadoop cluster is started, run the JPS command to view the process. Only the tasktracker process is found on the datanode node, as shown in.

Master process:

Two Slave node processes found that there was no datanode process on the salve node. after checking the log, we found that the data directory permission on datanode is 765, and the expected permission is 755. Therefore, we use the CHMOD 755 Data command, change the directory permission to 755. restart the hadoop cluster again and find that the datanode node has started properly.

After the hadoop cluster is started, the datanode node does not start properly.