To configure distributed virtual routers, there are a few requirements that must be met, including the following:

• ML2 plugin
• L2 population mechanism driver
• Open vSwitch mechanism driver
• Layer 3 agent installed on all networks and compute nodes

In the environment built out in this book, a single controller node handles OpenStack API services, DHCP and metadata services, and runs the Linux bridge agent for use with standalone and HA routers. compute01 runs the Linux bridge agent, while compute02 and compute03 run the Open vSwitch agent. Another node, snat01, will run the Open vSwitch agent and be responsible for outbound SNAT traffic when distributed virtual routers are used.

A diagram of this configuration can be seen here:

While the mixing of drivers and agents between nodes is possible thanks to the ML2 core plugin, a design like this is not typical in a production environment. Instances deployed on compute01 may experience connectivity issues if deployed on a network using a distributed virtual router.