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Environment Variables

Typically an application will require some configuration to run properly. Dokku supports application configuration via environment variables. Environment variables may contain private data, such as passwords or API keys, so it is not recommended to store them in your application's repository.

The config plugin provides the following commands to manage your variables:

config:show (<app>|--global)                                                          Pretty-print an app or global environment
config:bundle (<app>|--global) [--merged]                                             Bundle environment into tarfile
config:clear (<app>|--global)                                                         Clears environment variables
config:export (<app>|--global) [--envfile]                                            Export a global or app environment
config:get (<app>|--global) KEY                                                       Display a global or app-specific config value
config:keys (<app>|--global) [--merged]                                               Show keys set in environment
config:set [--encoded] [--no-restart] (<app>|--global) KEY1=VALUE1 [KEY2=VALUE2 ...]  Set one or more config vars
config:unset [--no-restart] (<app>|--global) KEY1 [KEY2 ...]                          Unset one or more config vars


For security reasons - and as per docker recommendations - Dockerfile-based deploys have variables available only during runtime, as noted in this issue. Consider using build arguments to expose variables during build-time for Dockerfile apps.

Environment variables are available both at run time and during the application build/compilation step for buildpack-based deploys.

For buildpack deploys, Dokku will create a /app/.env file that can be used for legacy buildpacks. Note that this is not updated when config:set or config:unset is called, and is only written during a deploy or ps:rebuild. Developers are encouraged to instead read from the application environment directly, as the proper values will be available then.


Global ENV files are sourced before app-specific ENV files. This means that app-specific variables will take precedence over global variables. Configuring your global ENV file is manual, and should be considered potentially dangerous as configuration applies to all applications.

You can set multiple environment variables at once:

dokku config:set node-js-app ENV=prod COMPILE_ASSETS=1

Whitespace and special characters get tricky. If you are using dokku locally you don't need to do any special escaping. If you are using dokku over ssh you will need to backslash-escape spaces:

dokku config:set node-js-app KEY="VAL\ WITH\ SPACES"

Dokku can also read base64 encoded values. That's the easiest way to set a value with newlines or spaces. To set a value with newlines you need to base64 encode it first and pass the --encoded flag:

dokku config:set --encoded node-js-app KEY="$(base64 ~/.ssh/id_rsa)"

When setting or unsetting environment variables, you may wish to avoid an application restart. This is useful when developing plugins or when setting multiple environment variables in a scripted manner. To do so, use the --no-restart flag:

dokku config:set --no-restart node-js-app ENV=prod

If you wish to have the variables output in an eval-compatible form, you can use the config:export command

dokku config:export node-js-app
# outputs variables in the form:
#   export ENV='prod'
#   export COMPILE_ASSETS='1'

# source in all the node-js-app app environment variables
eval $(dokku config:export node-js-app)

You can control the format of the exported variables with the --format flag. --format=shell will output the variables in a single-line for usage in command-line utilities:

dokku config:export --format shell node-js-app

# outputs variables in the form:
#   ENV='prod' COMPILE_ASSETS='1'

Special Config Variables

The following config variables have special meanings and can be set in a variety of ways. Unless specified via global app config, the values may not be passed into applications. Usage of these values within applications should be considered unsafe, as they are an internal configuration values that may be moved to the internal properties system in the future.


This list is not exhaustive, and may vary from version to version.

Name Default How to modify Description
DOKKU_ROOT ~dokku /etc/environment The root directory where dokku will store application repositories, as well as certain configuration files.
DOKKU_IMAGE gliderlabs/herokuish /etc/environment
The default image to use when building herokuish containers. Deprecated in favor of using buildpacks:set-property
DOKKU_LIB_ROOT /var/lib/dokku /etc/environment
The directory where plugins, certain data, and general configuration is stored.
PLUGIN_PATH $DOKKU_LIB_ROOT/plugins" /etc/environment
The top-level directory where plugins are stored.
PLUGIN_AVAILABLE_PATH $PLUGIN_PATH/available" /etc/environment
The directory that holds all available plugins, including core.
PLUGIN_ENABLED_PATH $PLUGIN_PATH/enabled" /etc/environment
The directory that holds all enabled plugins, including core.
PLUGIN_CORE_PATH $DOKKU_LIB_ROOT/core-plugins" /etc/environment
The directory that stores all core plugins.
The directory that stores all available core plugins.
The directory that stores all enabled core plugins.
DOKKU_LOGS_DIR /var/log/dokku /etc/environment
Where dokku logs should be written to.
A path on the host that will be mounted into the vector logging container.
DOKKU_EVENTS_LOGFILE $DOKKU_LOGS_DIR/events.log /etc/environment
Where the events log file is written to.
DOKKU_APP_NAME none --app APP flag Name of application to work on. Respected by core plugins.
DOKKU_APPS_FORCE_DELETE none --force flag Whether to force delete an application. Also used by other plugins for destructive actions.
DOKKU_CHECKS_URL /etc/environment
Url displayed during deployment when no CHECKS file exists.
DOKKU_QUIET_OUTPUT none --quiet flag Silences certain header output for dokku commands.
DOKKU_RM_CONTAINER none dokku config:set
Deprecated: Whether to keep dokku run containers around or not.
DOKKU_TRACE none dokku trace:on
dokku trace:off
--trace flag
Turn on very verbose debugging.
DOKKU_APP_PROXY_TYPE nginx dokku proxy:set
DOKKU_APP_RESTORE 1 dokku config:set
dokku ps:stop
DOKKU_APP_SHELL /bin/bash dokku config:set Allows users to change the default shell used by Dokku for dokku enter and execution of deployment tasks.
DOKKU_APP_TYPE herokuish Auto-detected by using buildpacks or dockerfile
DOKKU_CHECKS_DISABLED none dokku checks:disable
DOKKU_CHECKS_ENABLED none dokku checks:enable
DOKKU_CHECKS_SKIPPED none dokku checks:skip
DOKKU_CHECKS_WAIT 5 dokku config:set Wait this many seconds for the container to start before running checks.
DOKKU_CHECKS_TIMEOUT 30 dokku config:set Wait this many seconds for each response before marking it as a failure.
DOKKU_CHECKS_ATTEMPTS 5 dokku config:set Number of retries for to run for a specific check before marking it as a failure
DOKKU_DEFAULT_CHECKS_WAIT 10 dokku config:set If no user-defined checks are specified - or if the process being checked is not a web process - this is the period of time Dokku will wait before checking that a container is still running.
DOKKU_DISABLE_PROXY none dokku proxy:disable
dokku proxy:enable
Disables the proxy in front of your application, resulting in publicly routing the docker container.
Disables removal of the ANSI prefix during deploys. Can be used in cases where the client deployer does not understand ansi escape codes.
DOKKU_DISABLE_APP_AUTOCREATION none dokku config:set Disables automatic creation of a non-existent app on deploy.
DOKKU_DOCKER_STOP_TIMEOUT 10 dokku config:set Configurable grace period given to the docker stop command. If a container has not stopped by this time, a kill -9 signal or equivalent is sent in order to force-terminate the container. Both the ps:stop and apps:destroy commands also respect this value. If not specified, the docker defaults for the docker stop command will be used.
DOKKU_DOCKERFILE_CACHE_BUILD none dokku config:set
DOKKU_DOCKERFILE_START_CMD none dokku config:set
DOKKU_PARALLEL_ARGUMENTS. none dokku config:set Allows passing custom arguments to parallel for ps:*all commands
DOKKU_PROXY_PORT automatically assigned /etc/environment
dokku config:set
DOKKU_PROXY_SSL_PORT automatically assigned /etc/environment
dokku config:set
DOKKU_SKIP_ALL_CHECKS none dokku config:set
DOKKU_SKIP_CLEANUP /etc/environment
When a deploy is triggered, if this is set to a non-empty value, then old docker containers and images will not be removed.
DOKKU_SKIP_DEPLOY dokku config:set
DOKKU_START_CMD none dokku config:set Command to run instead of /start $PROC_TYPE
DOKKU_SYSTEM_GROUP dokku /etc/environment
System group to chown files as.
DOKKU_SYSTEM_USER dokku /etc/environment
System user to chown files as.