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Installing Forem using Containers

If you encounter any errors with our Container setup, please kindly report any issues!

Installing prerequisites

These prerequisites assume you're working on an operating system supported by Docker or Podman.

Choosing a Container Engine

A container engine is software that runs and manages containers on a computer. One of the most widely known Container Engines is Docker, but there are many other Container Engines available, such as Podman, CRI-O, and LXD.

Forem supports two Container Engines: Docker and Podman.


Forem can be setup with Docker and Docker Compose on macOS or Linux systems.

Docker is available for many different operating systems. You may use Docker as your Container Engine on both macOS and Linux workstations. As of right now Docker is the only Container Engine for macOS and we recommend you follow the Docker Desktop on Mac, install instructions to get Docker and Docker Compose installed.

Docker also works well on Linux distributions that have not moved to cgroup v2. You can install it by following their Installation per distro to get Docker and you can install Docker Compose by following these instructions.


Forem can be setup with Podman and Podman Compose on Linux systems.

Podman is an FOSS project that provides a Container Engine that is daemonless which only runs on Linux systems. It can be run as the root user or as a non-privileged user. It also provides a Docker-compatible command line interface. Podman is available on many different Linux distributions and it can be installed by following these instructions.

Podman Compose is a an early project under development that is implementing docker-compose like experience with Podman. You can install it by following these instructions.

Setting up Forem

  1. Fork Forem's repository, e.g.

  2. Clone your forked repository, eg. git clone<your-username>/forem.git

  3. Set up your environment variables/secrets

    1. Create .env by copying from the provided template.env_sample (i.e. with bash: cp .env_sample .env).

      • .env is a personal file that is ignored in git.
      • .env lists all the ENV variables we use and provides a fake default for any missing keys.
    2. For any key that you wish to enter/replace:

      • You do not need "real" keys for basic development. Some features require certain keys, so you may be able to add them as you go. The test environment is isolated from changes to the .env file, if you want to set variables in both test and development, use a file named .env.local, or modify .env.test.local and .env.development.local.
      • The backend guide will show you how to get free API keys for additional services that may be required to run certain parts of the app.
      • Obtain the development variable and apply the key you wish to enter/replace. i.e.:

Running Forem with Docker via docker-compose

  1. Run bin/container-setup
  2. That's it! Navigate to http://localhost:3000

The script executes the following steps:

  1. docker-compose build
  2. docker-compose up

Running Forem with Podman via podman-compose

  1. Run bin/container-setup
  2. That's it! Navigate to http://localhost:3000

The script executes the following steps:

  1. podman-compose build
  2. podman-compose up

Known Problems & Solutions

Docker on Mac

  • In case rails server starts with the following message:

    Data update scripts need to be run before you can start the application. Please run rails data_updates:run (RuntimeError)

    run the following command:

    docker-compose run rails bundle exec rails data_updates:run