CDNService Baseline Example

This example validates the new CDNService and its integration with DomainNameService.

The current design keeps the two services loosely coupled:

• DNS explicitly exposes an include file through setInclude(...)
• CDN explicitly writes policy-specific include content through setIncludeContent(...)

The topology is built on top of the mini Internet and models a simple CDN with:

• one authoritative DNS server
• three edge sites
• one shared origin
• one service domain: www.example.com

The CDN uses region-aware DNS answers:

• East clients resolve to 10.181.0.100
• West clients resolve to 10.182.0.100
• Central clients resolve to 10.183.0.100

All three edge nodes proxy to the same origin at 10.184.0.10.

Topology

The example reuses the base topology from examples/internet/B00_mini_internet.

CDN components:

• DNS: AS150, 10.150.0.53
• East edge: AS181, 10.181.0.100
• West edge: AS182, 10.182.0.100
• Central edge: AS183, 10.183.0.100
• Shared origin: AS184, 10.184.0.10

Running

Generate the Docker output:

conda run -n seedpy310 python examples/internet/B30_CDN/cdn.py amd

This creates:

examples/internet/B30_CDN/output

Build and start the topology manually:

cd examples/internet/B30_CDN/output
DOCKER_BUILDKIT=0 docker compose build
docker compose up -d

Wait about 10-20 seconds for services to start.

Verifying

East client:

docker exec as150h-host_0-10.150.0.71 sh -lc 'getent ahostsv4 www.example.com'
docker exec as150h-host_0-10.150.0.71 sh -lc 'env -u http_proxy -u https_proxy -u HTTP_PROXY -u HTTPS_PROXY -u all_proxy -u ALL_PROXY curl --noproxy "*" -s -D - http://www.example.com:8080/ -o /dev/null'

West client:

docker exec as152h-host_0-10.152.0.71 sh -lc 'getent ahostsv4 www.example.com'
docker exec as152h-host_0-10.152.0.71 sh -lc 'env -u http_proxy -u https_proxy -u HTTP_PROXY -u HTTPS_PROXY -u all_proxy -u ALL_PROXY curl --noproxy "*" -s -D - http://www.example.com:8080/ -o /dev/null'

Central client:

docker exec as154h-host_0-10.154.0.71 sh -lc 'getent ahostsv4 www.example.com'
docker exec as154h-host_0-10.154.0.71 sh -lc 'env -u http_proxy -u https_proxy -u HTTP_PROXY -u HTTPS_PROXY -u all_proxy -u ALL_PROXY curl --noproxy "*" -s -D - http://www.example.com:8080/ -o /dev/null'

Expected results:

• East resolves to 10.181.0.100
• West resolves to 10.182.0.100
• Central resolves to 10.183.0.100
• HTTP responses include:
  • X-CDN-Origin: global_origin
  • X-CDN-Origin-IP: 10.184.0.10
  • X-CDN-Edge
  • X-CDN-Region
  • X-CDN-Edge-IP

What This Example Exercises

This example checks that:

• CDNService can bind virtual origin and edge nodes to concrete hosts
• final edge and origin configuration is rendered before container startup
• DomainNameService can host CDN-generated BIND views through an include file
• region-aware DNS steering and HTTP proxying work end to end

Files

• examples/internet/B30_CDN/cdn.py: baseline CDN built with CDNService
• examples/internet/B30_CDN/output: generated Docker deployment