Project Maturity

MetalLB is currently in beta.


MetalLB is being used in several production and non-production clusters, by several people and companies. It is bundled together with the major Kubernetes distributions for on premise deployments. Based on the infrequency of bug reports, MetalLB appears to be robust in those deployments.

In any case, no one is perfect and issues might happen. Please file bugs! We want to hear from you and address pain points.

Test coverage

The codebase has reasonable test coverage, and a good amount of end-to-end tests which covers against most part of regressions. Despite that, edge cases may have bugs, so if you find unexpected behaviours, please consider filing an issue.

Configuration format

The configuration format may change in backwards-incompatible ways as the project is refactored to support additional routing protocols and features.

Backward-incompatible changes to configuration will be rolled out in a “make before break” fashion: first there will be a release that understands the new and the old configuration format, so that you can upgrade your configuration separately from the code. The next release after that removes support for the old configuration format.

Release notes during beta will highlight any required changes to configuration when upgrading between versions, and give advance warning of removals planned for the following version.

Kubernetes compatibility

The MetalLB maintainers aim to keep compatibility with the supported versions of Kubernetes. If a kubernetes version is not supported anymore, the compatibility is provided on best effort basis.


Documentation exists, but hasn’t been battle-tested by many readers unfamiliar with the project. As such, it may be incomplete or confusing in parts.

If you find shortcomings in the documentation, please file bugs! Your perspective is very valuable, and we want to hear about what works and what doesn’t.


The MetalLB copyright was owned by Google, until March 2019. However, it was never an official Google project. The project doesn’t have any form of corporate sponsorship.

MetalLB was created by one person, working on MetalLB in their spare time as motivation allows. The original author has now been empowering a team of maintainers to assist with moving the project forward.

Most support and new feature development is at the mercy of the availability of this small group, so you should set your expectations accordingly.

If you would like to help improve this balance, contributions are very welcome! In addition to code contributions, donation of resources (hardware, cloud environments…) are also very welcome: the more different conditions we can test MetalLB in, the fewer bugs and regressions will be introduced!

Copyright © The MetalLB Contributors.
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