Environment variables for Docker Build

You can set the following environment variables to enable, disable, or change the behavior of features related to building:

See also BuildKit built-in build args.

You can express Boolean values for environment variables in different ways. For example, true, 1, and T all evaluate to true. Evaluation is done using the strconv.ParseBool function in the Go standard library. See the reference documentation for details.

BUILDKIT_COLORS

Changes the colors of the terminal output. Set BUILDKIT_COLORS to a CSV string in the following format:

$ export BUILDKIT_COLORS="run=123,20,245:error=yellow:cancel=blue:warning=white"

Color values can be any valid RGB hex code, or one of the BuildKit predefined colors.

Setting NO_COLOR to anything turns off colorized output, as recommended by no-color.org.

BUILDKIT_HOST

Introduced in Buildx v0.9.0

You use the BUILDKIT_HOST to specify the address of a BuildKit daemon to use as a remote builder. This is the same as specifying the address as a positional argument to docker buildx create.

Usage:

$ export BUILDKIT_HOST=tcp://localhost:1234
$ docker buildx create --name=remote --driver=remote

If you specify both the BUILDKIT_HOST environment variable and a positional argument, the argument takes priority.

BUILDKIT_PROGRESS

Sets the type of the BuildKit progress output. Valid values are:

• auto (default)
• plain
• tty

Usage:

$ export BUILDKIT_PROGRESS=plain

BUILDKIT_TTY_LOG_LINES

You can change how many log lines are visible for active steps in tty mode by setting BUILDKIT_TTY_LOG_LINES to a number (default to 6).

$ export BUILDKIT_TTY_LOG_LINES=8

EXPERIMENTAL_BUILDKIT_SOURCE_POLICY

Lets you specify a BuildKit source policy file for creating reproducible builds with pinned dependencies.

$ export EXPERIMENTAL_BUILDKIT_SOURCE_POLICY=./policy.json

Example:

{
  "rules": [
    {
      "action": "CONVERT",
      "selector": {
        "identifier": "docker-image://docker.io/library/alpine:latest"
      },
      "updates": {
        "identifier": "docker-image://docker.io/library/alpine:latest@sha256:4edbd2beb5f78b1014028f4fbb99f3237d9561100b6881aabbf5acce2c4f9454"
      }
    },
    {
      "action": "CONVERT",
      "selector": {
        "identifier": "https://raw.githubusercontent.com/moby/buildkit/v0.10.1/README.md"
      },
      "updates": {
        "attrs": {"http.checksum": "sha256:6e4b94fc270e708e1068be28bd3551dc6917a4fc5a61293d51bb36e6b75c4b53"}
      }
    },
    {
      "action": "DENY",
      "selector": {
        "identifier": "docker-image://docker.io/library/golang*"
      }
    }
  ]
}

BUILDX_BUILDER

Overrides the configured builder instance. Same as the docker buildx --builder CLI flag.

Usage:

$ export BUILDX_BUILDER=my-builder

BUILDX_CONFIG

You can use BUILDX_CONFIG to specify the directory to use for build configuration, state, and logs. The lookup order for this directory is as follows:

• $BUILDX_CONFIG
• $DOCKER_CONFIG/buildx
• ~/.docker/buildx (default)

Usage:

$ export BUILDX_CONFIG=/usr/local/etc

BUILDX_EXPERIMENTAL

Enables experimental build features.

Usage:

$ export BUILDX_EXPERIMENTAL=1

BUILDX_GIT_CHECK_DIRTY

Introduced in Buildx v0.10.4

When set to true, checks for dirty state in source control information for provenance attestations.

Usage:

$ export BUILDX_GIT_CHECK_DIRTY=1

BUILDX_GIT_INFO

Introduced in Buildx v0.10.0

When set to false, removes source control information from provenance attestations.

Usage:

$ export BUILDX_GIT_INFO=0

BUILDX_GIT_LABELS

Introduced in Buildx v0.10.0

Adds provenance labels, based on Git information, to images that you build. The labels are:

• com.docker.image.source.entrypoint: Location of the Dockerfile relative to the project root
• org.opencontainers.image.revision: Git commit revision
• org.opencontainers.image.source: SSH or HTTPS address of the repository

Example:

  "Labels": {
    "com.docker.image.source.entrypoint": "Dockerfile",
    "org.opencontainers.image.revision": "5734329c6af43c2ae295010778cd308866b95d9b",
    "org.opencontainers.image.source": "git@github.com:foo/bar.git"
  }

Usage:

• Set BUILDX_GIT_LABELS=1 to include the entrypoint and revision labels.
• Set BUILDX_GIT_LABELS=full to include all labels.

If the repository is in a dirty state, the revision gets a -dirty suffix.

BUILDX_NO_DEFAULT_ATTESTATIONS

Introduced in Buildx v0.10.4

By default, BuildKit v0.11 and later adds provenance attestations to images you build. Set BUILDX_NO_DEFAULT_ATTESTATIONS=1 to disable the default provenance attestations.

Usage:

$ export BUILDX_NO_DEFAULT_ATTESTATIONS=1

BUILDX_NO_DEFAULT_LOAD

When you build an image using the docker driver, the image is automatically loaded to the image store when the build finishes. Set BUILDX_NO_DEFAULT_LOAD to disable automatic loading of images to the local container store.

Usage:

$ export BUILDX_NO_DEFAULT_LOAD=1