Keepalived is a routing daemon that provides load balancing and high availability for Linux systems.
Keepalived solves the problem of building resilient infrastructure by combining three independent frameworks into a single daemon. It uses the Linux Virtual Server kernel module to deliver Layer 4 load balancing across server pools, implements the VRRP protocol for router failover and high availability, and runs health checkers that monitor real servers in real time to add or remove them based on their status. The tool also implements BFD to detect network failures in milliseconds, allowing fast failover when link or peer failures occur. Each framework can operate independently or work together, letting operators build exactly the resilient infrastructure they need.
Keepalived suits organizations running production infrastructure in data centers, ISPs, or on hardware vendor platforms where load balancing and failover are critical. It is appropriate for teams that need Layer 4 load balancing with automatic health checking and high availability through VRRP failover, and that want these capabilities in a single daemon rather than multiple tools. The tool works with both IPv4 and IPv6, supports multiple scheduling algorithms and forwarding methods, and can secure VRRP protocol advertisements using IPSEC-AH. A minimal floating IP failover between two nodes requires only a single configuration file.
The project maintains a robust architecture centered on an I/O multiplexer driving a multithreaded framework, with the daemon split into a minimalistic parent process that monitors dedicated child processes for VRRP, health checking, and BFD stacks. Development activity shows consistent engagement with the codebase through regular commits addressing bug fixes, feature enhancements, and protocol improvements. The project maintains comprehensive documentation including detailed software design documentation, a quick start guide, and community resources. Pull requests receive review and feedback from maintainers, indicating active stewardship of code quality and direction.
