Yes, you can install Plesk Onyx on Centos 7. The official Plesk Onyx iso are available with Centos 7 or Ubuntu 16.04 LTS. It's just a choice, personally I prefer ubuntu because most of my servers are running with debian/ubuntu distributions, but you will have the same features with Centos.I'd like to know if Plesk Onyx can on Centos 7 or not? what is the best OS to install Plesk Onyx on?