The Dell Technologies Reference Architecture for Red Hat OpenStack Platform version 16.1 provides the ability to enable DVR on all all the compute nodes in the solution.
DVR offers an alternative routing design to the centralized routing model. It isolates the failure domain of the controller node and optimizes network traffic by deploying the L3 agent and schedule routers on every compute node . By eliminating a centralized layer 3 agent, the routing that was performed by single node (primary controller), is now distributed across the compute node s using the local L3 agent. DVR follows the below routing flow rules:
- East-West traffic is routed directly on the compute node s in a distributed fashion.
- North-South traffic with floating IP is distributed and routed on the compute node s. This traffic requires the external network connects to each compute node .
- North-South traffic without floating IP allocates and still needs a dedicated Controller node.
- The L3 agent on the controller node is configured with a new dvr_snat mode so that the node serves only SNAT traffic.
- The Neutron metadata agent distributes and deploys on all compute node s. The metadata proxy service hosts all the distributed routers.