HAProxy Community Edition vs MetalLB

HAProxy Community Edition is free, self-hosted software for proxying TCP and HTTP applications, with high availability and load balancing. It is aimed especially at very high-traffic websites. HAProxy runs on Linux, where it is included with most mainstream distributions and is often deployed by default on cloud platforms. Its event-driven design uses light multithreading on SMP machines. The project lists Layer 4 and Layer 7 routing and TLS termination, along with TCP and HTTP support; recent versions also include QUIC and HTTP/3 features. Listed safeguards include chroot, privilege drops, fork prevention, strict protocol validation, and checks for impossible states. The site reports up to 2 million SSL requests per second and 100 Gbps of forwarded traffic on AWS Graviton2. HAProxy 3.4 is in development, and 3.4.6 is the latest listed release in that branch. Its features include dynamic backends, HTTP/2 flood protections, ACME improvements, experimental QMUX, and an OpenTelemetry filter. LTS branches receive five years of maintenance; other stable branches receive 12 to 18 months.

MetalLB provides network load balancing for Kubernetes clusters that do not run on a cloud provider. It assigns service IP addresses from operator-configured pools and announces them through ARP, NDP, or BGP, depending on the chosen mode. In layer 2 mode, one cluster machine announces an address using ARP for IPv4 or NDP for IPv6. In BGP mode, cluster machines peer with nearby routers, which can distribute traffic across multiple nodes. The recommended FRR-K8s mode supports BFD, IPv6, and merging additional FRR configuration. MetalLB is open source, with no paid plans listed. Installation options include Kubernetes manifests, Kustomize, Helm, and an Operator on OperatorHub. After installation it remains idle until configured with resources such as an IPAddressPool in its deployment namespace. Requirements include Kubernetes 1.13.0 or later, a compatible cluster network, and IPv4 addresses. The project lists AWS, Azure, DigitalOcean, and Google Cloud as unsupported and says it is generally incompatible with cloud providers. MetalLB describes itself as a beta project and cautions that its configuration format may change incompatibly as development continues.