As you can see, the error message sais to check the file /var/lib/ambari-agent/data/datanode/dfs_data_dir_mount.hist This files stores the last mount point for each hdfs folder. In your case, seems that you are trying to mount the HDFS folders on different paths so datanode doesn't start to prevent data loss. Fix the file to point to the new mount points and start the datanode. ... View more