Getting Plex Media Server working under EL7 is an absolute breeze. Here are the steps needed to get your own server up and rocking.
This is getting PMS installed via my yum repository.
yum install https://schotty.com/yum/plex_el7/schotty-plex-el7-release-1-1.noarch.rpm yum makecache yum install plexmediaserver
Fix the firewall to allow for PMS
firewall-cmd --permanent --add-port=32400/tcp firewall-cmd --reoad
Create Plex system group
This is at your discretion as to what to name it, but you will need a dedicated plex group. Ensure that your media folder(s) have group ownership of this media group account.
groupadd media usermod -G media plex usermod -G media YOURPRIMARYUSER
Enable and start the PMS daemon
systemctl enable plexmediaserver systemctl start plexmediaserver
Login & Configure
Then in a browser navigate to your server in web browser:
Then proceed to configure Plex as you see fit. One troubleshooting issue that is worth noting, is that Firefox has an issue with HTML5, so disable that in your web browser if you are having issues. This is a client side issue, not a server side one. Chrome and Edge do not currently have this bug.