# metallb/metallb

A network load-balancer implementation for Kubernetes using standard routing protocols

Repository: https://github.com/metallb/metallb
Canonical: https://ross.abutalabs.com/products/metallb
Homepage: https://metallb.io
Language: Go
License: Apache-2.0
License Family: permissive
Topics: kubernetes, bgp, load-balancer, bare-metal, arp, vrrp, keepalived, hacktoberfest, frr
Last push: 2026-08-17T02:55:38+00:00

## Health v2 (maintenance only)
Score: 94/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 98, release rhythm 86, longevity 100
- inputs: {"age_days": 3220, "days_push": 16, "days_rel": 98, "gap_med": 0, "n_releases_24m": 12}
- flags: none
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 8333, forks 1068 (observed 2026-08-28T04:10:20.356201+00:00)

## What it is
MetalLB is a network load-balancer implementation for bare-metal Kubernetes clusters that provides Services of type LoadBalancer using standard routing protocols. It operates in layer 2 (ARP/NDP) mode or BGP mode, integrating with standard network equipment so external traffic reaches cluster services.

## Use cases
- expose kubernetes services with external IPs on bare metal
- run loadbalancer services without a cloud provider
- advertise kubernetes service IPs via BGP to routers
- get loadbalancer IPs on a home lab kubernetes cluster
- replace NodePort services for production traffic
- announce service IPs using ARP on layer 2 networks

## When to choose
- you run Kubernetes on bare metal or unsupported on-prem environments where cloud LoadBalancers stay pending
- your routers speak BGP or your network supports ARP/NDP and you want standard protocol integration
- you need IPv4 and IPv6 address pools with Prometheus metrics and CRD-based configuration

## When to avoid
- your cluster runs on a managed cloud like AWS, GCP, or Azure, which provide their own load balancers
- your cloud or virtual network emulates ARP or lacks BGP support, breaking L2 and BGP modes
- you need a layer 7 (HTTP) load balancer rather than network-layer IP advertisement

## Facets
- artifact type: service
- maturity: active
- function: load-testing, networking, deployment, monitoring
- domain: networking, self-hosted, infrastructure-as-code
- platform: self-hosted, go
- tags: bgp, bare-metal, arp, vrrp, frr, loadbalancer, kubernetes-operator, crd, containers, kubernetes, docker, linux

## Member repositories
- metallb/metallb (main) score 94

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:10:20.356201+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:27:43.863506+00:00, confidence not recorded.
  - readme: https://github.com/metallb/metallb (fetched 2026-08-28T04:10:20.356201+00:00, sha fb1b66b8c369)
  - homepage: https://metallb.io (fetched 2026-08-29T08:27:41.180357+00:00, sha 720acb76d6cd)
  - site_page: https://metallb.io/installation/network-addons (fetched 2026-08-29T08:27:41.183270+00:00, sha d1bc231bfdb8)
  - site_page: https://metallb.io/installation (fetched 2026-08-29T08:27:41.185229+00:00, sha 5039bcfa0cd5)
  - site_page: https://metallb.io/installation/clouds (fetched 2026-08-29T08:27:41.187162+00:00, sha 6c0ab292d22e)
  - site_page: https://metallb.io/faq (fetched 2026-08-29T08:27:41.189033+00:00, sha 5bff4010281b)
  - site_page: https://metallb.io/apis (fetched 2026-08-29T08:27:41.190772+00:00, sha e2e19333acad)
- Data as of 2026-08-30T08:39:29.467469+00:00.