Just to make sure:

1
sudo yum update

Get the YUM package:

1
 sudo curl -o /etc/yum.repos.d/mssql-server.repo https://packages.microsoft.com/config/rhel/7/mssql-server-2017.repo

Install MS SQL:

1
sudo yum install -y mssql-server

Setup server:

1
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.

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sudo firewall-cmd --zone=public --add-port=1433/tcp --permanent
2
sudo firewall-cmd --reload

Done.

SOURCE

Install MSSQL to CentOS 7