Configuration reference

Global configuration values for earthly can be stored on disk in the configuration file.

By default, earthly reads the configuration file ~/.earthly/config.yml; however, it can also be overridden with the --config command flag option.


The earthly config file is a YAML formatted file that looks like:

  cache_size_mb: <cache_size_mb>
        url_instead_of: <url_instead_of>
        auth: https|ssh
        user: <username>
        password: <password>


    cache_size_mb: 20000
        url_instead_of: ""
        auth: https
        user: alice
        password: itsasecret


To quickly change a configuration item via the earthly command, you can use earthly config.

earthly config <key> <value>

For example

earthly config global.cache_size_mb 20000

Global configuration reference


Specifies the total size of the BuildKit cache, in MB. The BuildKit daemon uses this setting to configure automatic garbage collection of old cache. Setting this to 0, either explicitly or by omission, will cause BuildKit to use its internal default of 10% of the root filesystem.


Specifies the total size of the BuildKit cache, as a percentage (0-100) of the total filesystem size. When used in combination with cache_size_mb, the lesser of the two values will be used. This limit is ignored when set to 0.

secret_provider (experimental)

A custom user-supplied program to call which returns a secret for use by earthly. The secret identifier is passed as the first argument to the program.

If no secret is found, the program can instruct earthly to continue searching for secrets under .secret, by exiting with a status code of 2, all other non-zero status codes will cause earthly to exit.

For example, if you have:

  secret_provider: my-secret-provider

and my-secret-provider (which is accessible on your PATH):

set -e

if [ "$1" = "mysecret" ]; then
    echo -n "open sesame"
    exit 0

exit 2

Then when earthly encounters a command that requires a secret, such as

RUN --secret mysecret echo "the passphrase is $mysecret."

earthly will request the secret for mysecret by calling my-secret_provider mysecret.


All stdout data will be used as the secret value, including whitespace (and newlines). You may want to use echo -n to prevent returning a newline.

Any data sent to stderr will be displayed on the earthly console, this makes it possible to insert commands such as echo >&2 "here is some debug text" without affecting the contents of the secret.


When set to true, disables collecting command line analytics; otherwise, earthly will report anonymized analytics for invocation of the earthly command. For more information see the data collection page.


When set to true, disables sharing build logs after each build. This setting applies to logged-in users only.


The number of concurrent converters for speeding up build targets that use blocking commands like IF, WITH DOCKER --load, FROM DOCKERFILE and others.


The maximum parallelism configured for the BuildKit daemon workers. The default is 20.


Set this configuration to a lower value if your machine is resource constrained and performs poorly when running too many builds in parallel.


This option allows you to pass additional options to Docker when starting up the Earthly BuildKit daemon. Note that changes to these values will trigger earthly to restart BuildKit on the next run.

Bypass User Namespacing

The --userns flag can be set as follows:

  buildkit_additional_args: ["--userns", "host"]

Session Timeout

By default, BuildKit will automatically cancel sessions (i.e. individual builds) after 24 hours. This value can be overriden using the following option:

  buildkit_additional_args: ["-e", "BUILDKIT_SESSION_TIMEOUT=72h"]

Note that setting a value of zero 0 here will disable the feature entirely. This can be useful in cases where long-lived interactive sessions are used.


This option allows you to pass additional options to BuildKit. Note that changes to these values will trigger earthly to restart BuildKit on the next run.

Additional CA Certificates

Additional CA certificates can be passed in to BuildKit. This also requires a corresponding change in buildkit_additional_args.

  buildkit_additional_args: ["-v", "<absolute-path-to-ca-file>:/etc/config/"]
  buildkit_additional_config: |


Allows overriding Earthly's automatic MTU detection. This is used when configuring the BuildKit internal CNI network. MTU must be between 64 and 65,536.


Allows overriding Earthly's automatic ip_tables module detection. Valid choices are iptables-legacy or iptables-nft.

no_loop_device (obsolete)

This option is obsolete and it is ignored. Earthly no longer uses a loop device for its cache.


Allows to override the image used to run internal git commands (e.g. during GIT CLONE or IMPORT). This defaults to alpine/git:v2.30.1.


The default organization to use when performing Earthly operations that require an organization. Ignored when the --org CLI option is present, or when the EARTHLY_ORG environment variable are set.

Frontend configuration

This option allows you to specify what supported frontend you are using (Docker / Podman). By default, Earthly will attempt to discover the frontend in this order: Docker -> Podman -> None

For Docker:

  container_frontend: docker-shell

For Podman:

  container_frontend: podman-shell

You can use the following command to set the configuration option using the earthly CLI:

# Docker
earthly config 'global.container_frontend' 'docker-shell'

# Podman
earthly config 'global.container_frontend' 'podman-shell'

Git configuration reference

All git configuration is contained under site-specific options.

site-specific options


The git repository hostname. For example, or


Either ssh, https, or auto (default). If https is specified, user and password fields are used to authenticate over HTTPS when pulling from git for the corresponding site. If auto is specified earthly will use ssh when the ssh-agent is running and has at least one key loaded, and will fallback to using https when no ssh-keys are present.

See the Authentication guide for a guide on setting up authentication.


The HTTPS username to use when auth is set to https. This setting is ignored when auth is ssh.


The HTTPS password to use when auth is set to https. This setting is ignored when auth is ssh.


The strict_host_key_checking option can be used to control access to ssh-based repos whose key is not known or has changed. Strict host key checking is enabled by default, setting it to false disables host key checking. This setting is only used when auth is ssh.


Disabling strict host key checking is a bad security practice (as it makes a man-in-the-middle attack possible). Instead, it's recommended to record the host's ssh key to ~/.ssh/known_hosts; this can be done by running

ssh-keyscan <hostname> >> ~/.ssh/known_hosts


The ssh_command option can be used to override the ssh command that is used by git when connecting to an ssh-based repository. For example, if you need to connect to an outdated sshd-server which only supports the insecure RSA signature algorithm, you could set the ssh_command to ssh -o 'PubKeyAcceptedKeyTypes +ssh-rsa'.


Connect using a non-standard git port, e.g. 2222.


The prefix option is used to indicate where git repositories are stored on the server, e.g. /var/git/.


A regular expression defined to match git URLs, defaults to the <site>/([^/]+)/([^/]+). For example if the site is, then the default pattern will match<user>/<repo>.

See the Authentication guide for a guide on setting up authentication with self-hosted git repositories.

See the RE2 docs for a complete definition of the supported regular expression syntax.


If specified, a regular expression substitution will be performed to determine which URL is cloned by git. Values like $1, $2, ... will be replaced with matched subgroup data. If no substitute is given, a URL will be created based on the requested SSH authentication mode.

See the Authentication guide for a guide on setting up authentication with self-hosted git repositories.

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