Learning OpenStack Networking - Third Edition

Using keepalived and VRRP to provide redundancy

Keepalived is a software package for Linux that provides load balancing and high availability to Linux-based software and infrastructures.

The Virtual Router Redundancy Protocol, or VRRP, is a first hop redundancy protocol that aims to provide high availability of a network's default gateway by allowing two or more routers to provide backup for that address. If the active router fails, a backup router will take over the address within a brief period of time. VRRP is an open standard and is based on the proprietary Hot Standby Router Protocol, or HSRP, developed by Cisco.

Neutron uses keepalived, which utilizes VRRP, to provide failover between multiple sets of router namespaces.