Frequently Asked Questions
Everything you need to know about EarthBuild, the open-source community fork of Earthly, licensing, architecture, and migration.
What is EarthBuild and what is its relationship with Earthly?
EarthBuild is the official, community-supported and open-source fork of Earthly. It was initiated and endorsed by the Earthly community and creators to ensure that the core container-based build engine remains vibrant, fully open source, and continuously maintained under the Mozilla Public License 2.0 (MPL-2.0).
EarthBuild is a 100% drop-in replacement for existing Earthfiles and CLI workflows.
Is EarthBuild free and open source?
Yes, 100%. EarthBuild is released under the Mozilla Public License Version 2.0 (MPL-2.0). There are no closed-source enterprise tiers, no cloud telemetry lock-ins, and no sudden paywalls. All capabilities—including remote caching, satellite builds, and multi-platform compilation—are completely free for personal, team, and commercial use.
How is EarthBuild different from Dockerfiles?
Dockerfiles were designed specifically for creating container runtime images. EarthBuild takes Dockerfile's layer caching and container isolation, but expands it into a general-purpose build system:
- Artifact Output: EarthBuild can output local binaries, test reports, web bundles, and files directly to your host (
SAVE ARTIFACT ... AS LOCAL). - Multi-Target Dependency Graph: Targets can depend on other targets across folders and git repos.
- Parallel Execution: Independent targets (e.g.
+lint,+test,+compile) execute concurrently.
How does caching work in EarthBuild?
EarthBuild leverages BuildKit under the hood. It tracks the exact cryptographic hash of all declared inputs (files, arguments, dependencies). If an input hasn't changed, EarthBuild re-uses the cached layer in milliseconds.
You can also configure remote caching via any standard OCI container registry (GitHub Packages, Docker Hub, AWS ECR, GCP Artifact Registry) so your entire engineering team shares pre-computed build layers.
Do I need Docker installed to run EarthBuild?
No, Docker is not strictly required. EarthBuild supports Podman, Docker, and Apple container engines out-of-the-box by default.
EarthBuild automatically detects your local container runtime without manual daemon configuration. You can also connect to remote BuildKit daemons running in Kubernetes or a remote Linux VM.
How do I migrate from Earthly to EarthBuild?
Migration is instant because Earthfiles are 100% compatible. Simply install the earthbuild CLI (which provides the earth command) and run your builds as usual. No changes to your Earthfile syntax are required.
How are secrets handled during builds?
EarthBuild supports secure secret mounts via RUN --secret SECRET_NAME=+secrets/token .... Secrets are mounted only in memory during the execution of that specific command and are never baked into container image layers, build cache metadata, or output artifacts.