Version-specific features

Earthly makes use of feature flags to release new and experimental features. Some features must be explicitly enabled to use them.


Avoid using feature flags for critical workflows. You should only use feature flags for testing new experimental features. By using feature flags you are opting out of forwards/backwards semver compatibility guarantees. This means that running the same script in a different environment, with a different version of Earthly may result in a different behavior (i.e. it'll work on your machine, but may break the build for your colleagues or for the CI).

Earthly uses semantic versioning; once a new feature has reached stability, a new VERSION release will include the feature enabled by default.

Difference between the Earthly binary version and the Earthfile version

Earthly binary versions and Earthfile versions (declared via VERSION) follow the same minor versioning milestones, but are not the same.

The Earthly binary is able to run some older Earthfiles, but newer Earthfiles are not able to run on older Earthly binaries. The table below shows the compatibility matrix:

Upgrading to a newer version

In order to upgrade to VERSION 0.8 safely, follow these steps:

  1. If you are still using VERSION 0.5, upgrade those Earthfiles to VERSION 0.6 or VERSION 0.7.

  2. Upgrade your Earthly binary to 0.8 in CI and across your team. The Earthly 0.8 binary can run both VERSION 0.6 and VERSION 0.7 Earthfiles.

  3. Once everyone is using the Earthly 0.8 binary, upgrade your Earthfiles one by one to VERSION 0.8. It is ok to have a mix of VERSION 0.6, VERSION 0.7 and VERSION 0.8 Earthfiles in the same project. Earthly handles that gracefully.

When upgrading between VERSIONs, keep in mind that you will encounter backwards-incompatible changes. Check out the change log of each version for more information.

Specifying Version and features

Each Earthfile should list the current earthly version it depends on using the VERSION command. The VERSION command was first introduced under 0.5 and is required as of 0.7.

VERSION [<flags>...] <version-number>

Feature flags

Note that the features flags are disabled by default in Earthly versions lower than the version listed in the "status" column above.


Speeds up COPY transfers.

When enabled, Earthly will only send the files listed for the specific COPY command. Without this feature, Earthly sends the entire directory of files excluding files listed in the .earthlyignore file.


Changes the behavior of SAVE commands in a significant way

When enabled, Earthly will output artifacts resulting from SAVE ARTIFACT ... AS LOCAL ... and images resulting from SAVE IMAGE and also execute RUN --push commands only if they are connected to the main target through a chain of BUILD commands.

For example, chains like these will produce outputs (and possibly push, if enabled):

  • main target -> SAVE

  • main target -> BUILD -> SAVE

  • main target -> BUILD -> BUILD -> SAVE

  • main target -> BUILD -> BUILD -> BUILD -> SAVE

While chains like these will NOT produce outputs nor would they push:

  • main target -> FROM -> SAVE

  • main target -> COPY -> SAVE

  • main target -> FROM -> BUILD -> SAVE

  • main target -> BUILD -> FROM -> SAVE

  • main target -> BUILD -> BUILD -> COPY -> SAVE

This works the same regardless of whether the targets in the chain are remote or local.

When this feature is disabled, Earthly will output artifacts and images regardless of whether they are connected to the main target through a chain of BUILD commands, however the outputs will be subject to the following rules:

  • All SAVE ARTIFACT ... AS LOCAL ..., with local Earthfiles will be output

  • SAVE ARTIFACT ... AS LOCAL ... produced in remote targets will not be output

  • All images with tag names (both local and remote Earthfiles) will be output

  • No image will be pushed or RUN --push command will be executed if the target is remote


Enables support for FOR ... IN ... commands

When enabled, Earthly will allow the use of FOR ... IN ... commands.

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