Hope you are doing well.
Please use below command
su - hdfs -c "/usr/hdp/current/hadoop-client/sbin/hadoop-daemon.sh start namenode"
su - hdfs -c "/usr/hdp/current/hadoop-client/sbin/hadoop-daemon.sh start datanode"
Verify that the DataNode process is up and running:
ps -ef|grep DataNode
Verify that NameNode can go out of safe mode.
su - hdfs -c "hdfs dfsadmin -safemode wait"
You should see the following result: Safe mode is OFF
Hope it will help you to resolve your query.
If you have any further query,please let us know.