Learning OpenStack Networking - Third Edition

Using the routing policy database

When a virtual machine instance without a floating IP sends traffic destined to an external network such as the internet, it hits the local qrouter namespace on the compute node and is routed to the snat namespace on the centralized network node. To accomplish this task, special routing rules are put in place within the qrouter namespaces.

Linux offers a routing policy database made up of multiple routing tables and rules that allow for intelligent routing based on destination and source addresses, IP protocols, ports, and more. There are source routing rules for every subnet a virtual router is attached to.

In this demonstration, the router is attached to a single project network: 172.24.100.0/24. Take a ...