Installing as non-root in a root owned directory
 

All,
I have a machine which has only /opt with some decent amount of space where I can install a software. /opt belongs to root:root. The software I want to install cannot be installed as root user.
So lets say I create a directory called /opt/install1 and then chown -R install1 to belong to user1. And now I install the software under /opt/install1 with user as user1.
Is this a best practice violation? There could potentially be just /opt/install1 belong to user1 and in future everything else created under /opt belonging to root..Thanks!

This is not a "violation" or even a problem. It is normal that higher level directories are inaccessible by users and subdirectories are chown'ed to be accessible the way you suggested.

If you think about it / which is the top of the hierarchy is never owned by any regular user yet any other subdirectories on the system may be. A good example is /home. The directory itself is not owned by any specific user yet all of the home directories under it are owned by their respective users.

CAUTION: If you use "-R" with chown be sure NEVER to do "chown -R .*" as that would make it chown the parent directory and all its other subdirectories because ".*" would match "..".

Thanks!