Create and chown default HDFS data directory or chown EC2 volume mount points if available.
Replace deprecated dfs.data.dir setting with dfs.datanode.data.dir and configure it with default directory or EC2 volume mount points if available.
Restart YARN resource manager to remove duplicate nodes after node manager restarts.
Limit the amount of physical memory allocatable on nodes and request able by resource manager to 1GB less total memory on node (previously default of 8192 MB).