This image shows an Oracle Cloud Infrastructure region, which contains a single Availability Domain. A Virtual Cloud Network (VCN) spans the region and the Availability Domain. This VCN contains a public subnet and a private subnet. Traffic to these subnets in controlled by a routing table. Within the availability domain, the public subnet contains and instance of the Drupal CMS and the private subnet contains an instance of a MySQL Database Service. Access to both of these components is controlled by way of security lists.

Access to the VCN from the region is through an Internet Gateway. Traffic flows bidirectionally between the gateway and the CMS and between the CMS and database service.