How to restart NameNode or all the daemons in Hadoop?

[#1]

In Hadoop how to restart NameNode or all the daemons?

[#2]

@Himani Bansal

It can be done using Ambari UI or API calls.

https://docs.hortonworks.com/HDPDocuments/Ambari-2.6.2.0/bk_ambari-operations/content/rolling_restar...

https://docs.hortonworks.com/HDPDocuments/Ambari-2.6.2.0/bk_ambari-operations/content/setting_rollin...

API calls:

https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=41812517

[#3]

By following methods we can restart the NameNode:

• You can stop the NameNode individually using /sbin/hadoop-daemon.sh stop namenode command. Then start the NameNode using /sbin/hadoop-daemon.sh start namenode.
• Use /sbin/stop-all.sh and the use /sbin/start-all.sh, command which will stop all the demons first. Then start all the daemons.
  The sbin directory inside the Hadoop directory store these script files.