Buildbarn

C
C tier on Build Cache SoftwareScore 6.3 · #12 of 23
Android app
Not listed
Free plan
No
Runs on
api, Linux, self-hosted
github.com
The Buildbarn homepage

Summary

Buildbarn Remote Execution is an open-source toolkit for creating a build farm that runs build actions remotely. It provides a scheduler to queue actions, a worker to coordinate execution and file transfers, and a runner to execute commands. Bazel, BuildStream, and recc are named as clients that can call a Buildbarn build farm. The tools work with Buildbarn’s storage daemon, and deployments can range from a single-node remote caching setup to large-scale remote execution. Buildbarn provides container images and example deployments, including Docker Compose and Kubernetes configurations. Separating worker and runner processes supports privilege separation intended to help prevent build actions from overwriting input files. The worker communicates with the runner through a gRPC-based protocol, which allows custom runner implementations, including one using QEMU user-mode emulation. The runner’s bare image contains no userland or Linux installation, so build actions may need a userland environment. The deployment guide also notes possible glibc version mismatches between build and remote environments. The remote execution repository lists an Apache-2.0 license.

Who it is for

Buildbarn may suit teams that need self-hosted remote build execution or caching and use tools such as Bazel, BuildStream, or recc. It also offers a route to custom runner implementations and container-based deployment.

What is good

  • Open-source under Apache-2.0.
  • Provides scheduler, worker, and runner components.
  • Supports container-based deployment examples.
  • Can scale from single-node caching to large execution setups.
  • Worker-runner separation supports privilege separation.

What to know first

  • Remote execution depends on Buildbarn’s storage daemon.
  • Bare runner image contains no userland or Linux installation.
  • Remote builds may encounter glibc version mismatches.

Verdict

Buildbarn provides the core services and deployment examples for remote build execution, from caching to larger setups. Build actions may require a userland environment, and the deployment guide identifies glibc mismatches as a possible issue.

Compared on build cache software

Cache scope
bothgithub.com
Self-hosted option
Yesgithub.com
Supported build systems
Bazel, Buck2, BuildStream, recc, Pants, Gomagithub.com
CI platform support
GitHub Actionsgithub.com
Remote execution
Yesgithub.com
Open source
Yesgithub.com

Facts

Purpose
Buildbarn Remote Execution provides tools to create a build farm for remotely executing build actions.github.com · 4 Oct 2026
Build services
The repository provides bb_scheduler to queue build actions, bb_worker to coordinate their execution and file transfers, and bb_runner to execute commands.github.com · 4 Oct 2026
Build clients
The project README names Bazel, BuildStream, and recc as tools that can call into a Buildbarn build farm.github.com · 4 Oct 2026
Security design
Separating bb_worker and bb_runner enables privilege separation intended to prevent build actions from overwriting input files.github.com · 4 Oct 2026
Extensibility
bb_worker communicates with bb_runner over a gRPC-based protocol, allowing custom runner implementations such as one using QEMU user-mode emulation.github.com · 4 Oct 2026
Deployment
The project provides container images for its components and links to example deployments.github.com · 4 Oct 2026
Deployment scale
Buildbarn deployments can range from single-node remote caching setups to large-scale remote execution setups.github.com · 4 Oct 2026
Operational requirement
The bb_runner_bare image contains no userland or Linux installation, and build actions may require a userland environment.github.com · 4 Oct 2026
Support
The Buildbarn storage repository points users to a Slack channel and says commercial support and hosting can be procured through partners.github.com · 4 Oct 2026
License
The bb-remote-execution repository identifies its license as Apache-2.0.github.com · 4 Oct 2026
Remote execution tools
The remote execution repository provides a scheduler, worker, and runner for queuing and executing build actions.github.com · 5 Oct 2026
Execution architecture
The worker communicates with the runner over a gRPC-based protocol, allowing a custom runner such as one using QEMU user-mode emulation.github.com · 5 Oct 2026
Privilege separation
Separating worker and runner processes supports privilege separation to help prevent build actions from overwriting cached input files.github.com · 5 Oct 2026
Storage dependency
Remote execution tools work in combination with Buildbarn’s storage daemon.github.com · 5 Oct 2026
Deployment options
The project provides container images for its components, and its deployment examples include Docker Compose and Kubernetes configurations.github.com · 5 Oct 2026
Scale
Buildbarn deployment examples describe use cases ranging from single-node remote caching to large-scale remote execution.github.com · 5 Oct 2026
Security configuration
The storage daemon supports configurable authorizers for cache and execution operations; its README example uses allow-all authorizers.github.com · 5 Oct 2026
Monitoring
The storage daemon configuration supports Prometheus metrics and pprof diagnostics.github.com · 5 Oct 2026
Commercial hosting
Listed commercial hosting options include self-hosted managed Buildbarn and cloud-hosted Buildbarn services.github.com · 5 Oct 2026
Deployment caveat
The Buildbarn deployment guide notes that remote builds can encounter glibc version mismatches between the build environment and the remote environment.github.com · 5 Oct 2026

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