This image shows an Oracle Cloud Infrastructure region that includes a domain name system (DNS) service. The region includes a single availability domain with three fault domains. The availability domain includes a virtual cloud network (VCN) with three regional subnets and an internet gateway. Each subnet provides its own routing table and security list access. The regional subnets are arranged as functional layers:

• Load balancer layer (regional public subnet): The load balancer resides in fault domain 3 and connects to the internet gateway and to the nodes in the Varnish Enterprise layer. A standby load balancer resides in fault domain 2.

• Varnish Enterprise layer (regional public subnet): The layer contains a block labeled Varnish Enterprise with auto-scaling. The block spans fault domains I and 2 and is connected to the load balancer layer. The Varnish Enterprise block includes two virtual machine nodes connected to each other and to their own file storage instances separate fault domains in the file storage layer.

• File storage layer (regional private subnet): File storage for session information is provided outside of the fault domains and is connected to the Varnish Enterprise block.