Testing tricky network services with Linux Namespaces
2 days ago
- #Testing
- #Linux
- #Networking
- The article discusses using Linux network namespaces to test tricky network services, specifically focusing on DHCP load balancing (dhcplb).
- The author needed a scalable and scriptable solution for testing DHCP services without dedicated hardware, leading to the use of Linux namespaces, veth pairs, and bridges.
- Network namespaces provide isolated network stacks, veth pairs connect namespaces, and bridges act as virtual switches to create complex network topologies.
- Two main topologies are described: a relay mode with four actors (client, relay, dhcplb, server) and a server mode with three actors (client, dhcplb, bridge).
- The setup involves creating namespaces, bridges, and veth pairs, then assigning IP addresses and running services within the namespaces.
- For macOS users, Lima (Linux virtual machines) is used to run the Linux-based tests seamlessly.
- The article includes detailed steps for setting up and testing both relay and server modes, with configuration examples for dnsmasq and dhcplb.
- The tests are automated using a Makefile, making it easy to build, run, and tear down the test environments.
- The solution proved effective, with the author's PR passing CI integration tests on GitHub.
- The article concludes by highlighting the power of namespaces for testing complex network services and encourages readers to explore this approach.