OS level changes for elasticsearch

Whether only in the data nodes (cluster environment with master nodes, co-coordinating nodes..etc) the changes for file descriptors , virtual memory..etc needs to be done?

Files to be updated.
/etc/sysctl.conf
/etc/security/limits.conf

Even though this is mostly needed for data nodes, you'll have to do this on all nodes. Otherwise the bootstrap checks will still complain.

Sure. Thanks.