Again, another brain dump for future use. A stock installation of CentOS 7 will be packaged with PHP 5.4 which is now end of life. This is how to install PHP 5.6, which is currently only receiving security updates.

Side note: These commands install the basic PHP requirements for Magento.

Installing PHP 5.6 on CentOS 7 via Webtatic

$ rpm -Uvh
$ rpm -Uvh
$ yum install php56w php56w-opcache php56w-xml php56w-mcrypt php56w-gd php56w-devel php56w-mysql php56w-intl php56w-mbstring php56w-bcmath php56w-soap

Further Documentation:

Installing PHP 5.6 on CentOS 7 via IUS

yum -y install epel-release
rpm -Uvh ius-release*.rpm
yum -y update
yum -y install php56u php56u-opcache php56u-xml php56u-mcrypt php56u-gd php56u-devel php56u-mysql php56u-intl php56u-mbstring php56u-bcmath php56u-soap

You can also install php-fpm via these repositories. For example: yum install php56w-fpm (webtatic) or yum install php56u-fpm (ius)