DHCPLB: An open source load balancer

What this post added

This post introduces DHCPLB, an open-source load balancer developed to address significant DHCP traffic imbalance issues observed in Meta's data centers. The post details the problem of uneven request distribution across DHCP servers (KEA) due to network topology and anycast limitations, which led to outages. It describes the development of DHCPLB through hackathons and intern projects, highlighting its features like DHCPv6 support, A/B testing capabilities for KEA server updates, MAC address-based overrides, integration with monitoring infrastructure, hot-reloading configuration, BGP advertisement, and two balancing algorithms. The successful rollout of DHCPLB in production demonstrated improved load balancing and simplified testing of DHCP infrastructure, directly contributing to enhanced site reliability.