What will happen if ES is installed with root user and try to start with other non-root user ?

Problem

Following error occurred :

java.io.FileNotFoundException: /home/shaan/ELK/elasticsearch-2.2.0/logs/my-application-shaandev.log (Permission denied)

Possible cause 

You must have started ES with a non-root user (In this case ES is installed using the root user), which made <cluster.name>.log file with root user.

Now, when you try to start ES with proper user (non-root) , it’s not able to access this log file created by root.

Solution

Delete the file <cluster.name>.log (which is my-application-shaandev.log) or change the permission of it, then start it again.