Why it is recommended to make changes through ambari rather than going to server and make changes ?

[#1]

I have to change yarn.nodemanager.linux-container-executor.nonsecure-mode.limit-users property value, but i changed yarn-site.xml going to server, instead of doing this we can go to ambari and change custom-site.

but i do not understand why first method is not recommended ?

[#2]

@Anurag Mishra

If you will make changes to any script or configuration file (like hdfs-site.xml/core-site.xml) manually then it will work only when you will start those components manually.

But if you will start those components from Ambari then ambari will use the same configuration (which is stored in the ambari DB) to start/stop those components from ambari UI.

So your manual changes will be overwritten by ambari. Hence you should not make manual changes to the scripts or XML files on individual hosts when managing cluster via ambari, else upon restart of those services your manual changes will be overwritten (gone).

[#3 · Accepted solution]

Hi @Anurag Mishra,

If you want to change yarn-site.xml in the server, then it is also fine. But you need to restart the services on your own instead of using ambari .(if you use ambari to restart services, then as mentioned by Jay, your changes will get wiped off)

WARNING : It so happens, that for some properties in yarn-site.xml, it requires restart of more than one service , in which case, you need to copy the change in all service nodes and restart them.

ADVANTAGE OF AMABRI - In case of ambari, its just one point change, it will figure out which services require that change and suggest restart of all the services required.