Just to make sure:

sudo yum update

Get the YUM package:

 sudo curl -o /etc/yum.repos.d/mssql-server.repo https://packages.microsoft.com/config/rhel/7/mssql-server-2017.repo

Install MS SQL:

sudo yum install -y mssql-server

Setup server:

sudo /opt/mssql/bin/mssql-conf setup

Open network firewall for 1433 (default port for MSSQL) so that it could be accessed from other machine.

sudo firewall-cmd --zone=public --add-port=1433/tcp --permanent
sudo firewall-cmd --reload

Done.

SOURCE