Hi @Kumar Veerappan, You can find namenode via command line using : dfsadmin -report or <code>hadoop getconf -namenodes ( you can use this to get secondary namenode/backup node etc)
From ambari, you can go to services page, get to the service whose admin you want and click on the component link to find the component host. For eg, to find the namenode go to HDFS service page and click on the link for namenode : Else, move to the hosts page and search for the component : screen-shot-2016-08-05-at-114146-am.png Based on the version you are using, the filter page may vary. But every version has a filter for component type which will give you host name. Hope this helps!
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