Distributed DHCP

Current Neutron Reference Implementation

The DHCP server is implemented using the Dnsmasq server running in a namespace on the newtork-node per tenant subnet that is configured with DHCP enabled.

Currently High availability is achieved by running multiple Dnsmasq servers on multiple Network nodes.

There is a namespace with Dnsmasq server per tenant subnet

Problems with current DHCP implementation:

1. Management and Scalability - Need to configure and mange multiple Dnsmasq instances
2. Centralize solution depended on the network node

DHCP agent

Same Concept as L3 agent and namespaces for virtual router. Using black boxes that implement functionality and using them as the IaaS backbone implementation

Distributed DHCP In Dragonflow

Dragonflow distribute DHCP policy/configuration using the pluggable DB. Each controller read this DB and install hijacking OVS flows for DHCP traffic and send that traffic to the controller.

The controller dispatch this to the local DHCP application which answer with local DHCP acks.

The following diagrams demonstrate this process: