projectcalico/calico

LoadBalancer IPAM: support IP assignment with `Service.spec.externalIPs/loadBalancerIP`

Open

#11,815 opened on Feb 10, 2026

View on GitHub
 (5 comments) (1 reaction) (0 assignees)Go (1,594 forks)auto 404
good first issuehelp wantedkind/enhancement

Repository metrics

Stars
 (7,292 stars)
PR merge metrics
 (PR metrics pending)

Description

We use Calico for BGP peering and announcing Service IPs to the upstream fabric.

BGPConfiguration allows Services from pre-defined ranges to be used and announced:

› kubectl get bgpconfiguration default -oyaml | yq .spec.serviceLoadBalancerIPs
- cidr: 10.10.10.0/24
- cidr: 192.168.0.0/27

It would be great if Loadbalancer controller would not only tolerate projectcalico.org/loadBalancerIPs for manual assignment but also actual Service.spec.externalIPs and Service.spec.loadBalancerIP.

This would help to gradually migrate existing charts when payload is deployed to clusters where Calico LoadBalancer IP address management is used without having to switch the whole chart fleet to the Calico-specific annotation.

Contributor guide

Research direction
Investigate the LoadBalancer IPAM code in Calico (likely in the `pkg/controller/loadbalancer` or similar) to understand current annotation based assignment. Then, extend the logic to also check and assign IPs from `Service.spec.externalIPs` and `Service.spec.loadBalancerIP` when present, ensuring compatibility with existing behavior.
Tech stack
go
Domain
backendinfrastructure
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GoKubernetesCalico
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
45