http://www.tecmint.com/things-to-do-after-minimal-rhel-centos-7-installation/#C6
before installing apache, fix the hostname, /etc/hosts file
=================================================
Install Apache
=================================================
# yum install httpd
LISTEN 80 , change it to any port you like
# firewall-cmd --add-service=http
# firewall-cmd --permanent --add-port=3221/tcp
# firewall-cmd --reload
# systemctl restart httpd.service
# systemctl start httpd.service
# systemctl enable httpd.service
=================================================
Install...