The OpenStack Networking (neutron) service has a scheduler that lets you run multiple agents across nodes. The DHCP agent can be natively highly available.
To configure the number of DHCP agents per network, modify the
dhcp_agents_per_network parameter in the
file. By default this is set to 1. To achieve high availability, assign more
than one DHCP agent per network. For more information, see
High-availability for DHCP.