Project Maturity

MetalLB is currently in alpha.


MetalLB is being used in several production and non-production clusters, by several people and companies. So far, it appears to be very stable in those deployments, but in the grand scheme of things, MetalLB is still not hugely “battle tested.”

If you use it today, you’ll be an early adopter and may encounter more issues than usual. Please file bugs! We want to hear from you and address pain points.

Test coverage

The codebase has reasonable test coverage, but lacks comprehensive end-to-end tests. Empirical testing, combined with the unit tests we have, show that the common codepaths work properly, but edge cases may have bugs.

Increasing test coverage is an active area of work.

Configuration format

The configuration format was grown organically during the prototyping phase, and may change in backwards-incompatible ways as the project is refactored to support additional routing protocols and features.

Release notes during alpha will highlight any required changes to configuration when upgrading between versions. Stabilization of the configuration format is the main blocker for graduating MetalLB to “beta” status.


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.


While MetalLB’s copyright is owned by Google, this is not an official Google project. The project have any other form of corporate sponsorship, other than GCP credits generously provided by Google to run test infrastructure.

The majority of code changes, as well as the overall direction of the project, is a personal endeavor of one person, working on MetalLB in their spare time.

This means that, currently, support and new feature development is mostly at the mercy of one person’s availability and resources. You should set your expectations appropriately.

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!