environment-variables.md

Order	Area	TOCTitle	PageTitle	ContentId	MetaDescription	DateApproved
2	advancedcontainers	Environment variables	Container environment variables	031424a7-ab0e-42e0-ab7d-30a5371b9a50	Use environment variables in containers	04/03/2025

Environment variables

You can set environment variables in your container without altering the container image by using one of the options below.

You should verify Terminal > Integrated: Inherit Env is checked in settings or the variables you set may not appear in the Integrated Terminal. This setting is checked by default.

Option 1: Add individual variables

Depending on what you reference in devcontainer.json:

• Dockerfile or image: Add the containerEnv property to devcontainer.json to set variables that should apply to the entire container or remoteEnv to set variables for VS Code and related sub-processes (terminals, tasks, debugging, etc.):

  "containerEnv": {
      "MY_CONTAINER_VAR": "some-value-here",
      "MY_CONTAINER_VAR2": "${localEnv:SOME_LOCAL_VAR}"
  },
  "remoteEnv": {
      "PATH": "${containerEnv:PATH}:/some/other/path",
      "MY_REMOTE_VARIABLE": "some-other-value-here",
      "MY_REMOTE_VARIABLE2": "${localEnv:SOME_LOCAL_VAR}"
  }

  As this example illustrates, containerEnv can reference local variables and remoteEnv can reference both local and existing container variables.

Video: Modify PATH in a dev container

<iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/vEb7hKlagAU" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>

• Docker Compose: Since Docker Compose has built-in support for updating container-wide variables, only remoteEnv is supported in devcontainer.json:

  "remoteEnv": {
      "PATH": "${containerEnv:PATH}:/some/other/path",
      "MY_REMOTE_VARIABLE": "some-other-value-here",
      "MY_REMOTE_VARIABLE2": "${localEnv:SOME_LOCAL_VAR}"
  }

  As this example illustrates, remoteEnv can reference both local and existing container variables.

  To update variables that apply to the entire container, update (or extend) your docker-compose.yml with the following for the appropriate service:

  version: '3'
  services:
    your-service-name-here:
      environment:
        - YOUR_ENV_VAR_NAME=your-value-goes-here
        - ANOTHER_VAR=another-value
       # ...

If you've already built the container and connected to it, run Dev Containers: Rebuild Container from the Command Palette (kbstyle(F1)) to pick up the change. Otherwise run Dev Containers: Open Folder in Container... to connect to the container.

Option 2: Use an env file

If you have a large number of environment variables that you need to set, you can use a .env file instead.

First, create an environment file somewhere in your source tree. Consider this .devcontainer/devcontainer.env file:

YOUR_ENV_VAR_NAME=your-value-goes-here
ANOTHER_ENV_VAR_NAME=your-value-goes-here

Next, depending on what you reference in devcontainer.json:

• Dockerfile or image: Edit devcontainer.json and add a path to the devcontainer.env :

  "runArgs": ["--env-file",".devcontainer/devcontainer.env"]

• Docker Compose: Edit docker-compose.yml and add a path to the devcontainer.env file relative to the Docker Compose file:

  version: '3'
  services:
    your-service-name-here:
      env_file: devcontainer.env
      # ...

docker compose will automatically pick up a file called .env in the folder containing the docker-compose.yml, but you can also create one in another location.

If you've already built the container and connected to it, run Dev Containers: Rebuild Container from the Command Palette (kbstyle(F1)) to pick up the change. Otherwise run Dev Containers: Open Folder in Container... to connect to the container.

Video: Load variables from an .env file

<iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/qTU7w3bWrOk" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen=""></iframe>