Mastodon Docker Setup

mastodon-docker-setup.md

Mastodon Docker Setup

Setting up

Clone Mastodon's repository.

# Clone mastodon to ~/mastodon directory
git clone https://github.com/mastodon/mastodon.git
# Change directory to ~/mastodon
cd ~/mastodon
# Checkout to the latest stable branch
git checkout $(git tag -l | grep -v 'rc[0-9]*$' | sort -V | tail -n 1)

Review the settings in docker-compose.yml.

Getting the Mastodon image

Installing Docker containers

If you're not making any local code changes or customizations on your instance, you can use a prebuilt Docker image to avoid the time and resource consumption of a build.

1. Open docker-compose.yml in your favorite text editor.
2. Add environment variables to the db section:

   environment:
     - POSTGRES_PASSWORD: xyz <-- choose a safe one, 20-30 chars
     - POSTGRES_DB: mastodon_production
     - POSTGRES_USER: mastodon
     - POSTGRES_HOST_AUTH_METHOD: trust

3. To use pre-built images:
   1. Comment out the build: . lines for the web, streaming, and sidekiq services.
   2. Edit the three image: tootsuite/mastodon lines to include the release you want. The default is latest which is the most recent stable version, however it recommended to explicitly pin a tagged version. If you wanted to use v3.4.1 for example, you would edit the lines to say: image: tootsuite/mastodon:v3.4.1. Visit https://hub.docker.com/r/tootsuite/mastodon/ to see the available tags.
4. Save the file and exit the text editor.
5. Run docker-compose build to either pull or build the necessary container images.
6. Create the public/system dir with mkdir public/system
7. Set correct file-owner with sudo chown -R 991:991 public/system

Configuration

Next generate a configuration with:

docker-compose run --rm web bundle exec rake mastodon:setup

This is an interactive wizard that will guide you through the options and generate app secrets.

1. Enter the Fully Qualified Domain Name (FQDN) of your mastodon instance.
2. Select if you want a Single User instance (not recommended, but if you prefer, use that).
3. Obviously, you are running mastodon in a docker instance, so type Y (or hit return, as it's the default)
4. The PostgreSQL host is db, the port is 5432 (again, default), the database is mastodon_production, the database user is mastodon and the password is the one you chose and put into docker-compose.yml.
5. The redis server is redis, the port is 6379 and the password is empty.
6. If you want to store uploaded files on the cloud, enter Y here and put in the necessary data.
7. If you want to send emails from the local machine, enter Y. I chose N and was able to send email via a free mailgun account. Accept the default port then enter the user and password for the email sending account. Select the SMTP authentication type plain and none for OpenSSL verify mode. Choose what sender address the emails will have. mastodon@*yourdomain.com* is a decent possibility.

Now it will output your configuration. Copy and paste that into the .env.production file.

The wizard will setup the database schema and precompile assets. After it's done, you can launch Mastodon with:

docker-compose up -d

Reverse Proxy

You need a Reverse Proxy in front of your Mastodon instance. The most used and best documented for Mastodon is nginx. In case you have an Apache running on port 80 anyway, you can also use that apache2 instance as a reverse proxy.

nginx Configuration

You need to configure nginx to serve your Mastodon instance.

Copy the example nginx.conf to a specific one for your domain:

sudo cp dist/nginx.conf /etc/nginx/sites-available/example.com.conf

Then edit the file to replace example.com with your domain, and adust the root lines so they point to your installation. In my case I had to change the username and remove live/

Activate the configuration you added:

sudo ln -s ../sites-available/example.com.conf /etc/nginx/sites-enabled

SSL setup with Let's Encrypt

This depends on your host operating system. My experience is that DigitalOcean's setup documents work well for multiple Ubuntu and Debian versions.

Restart Nginx

To finish up, restart nginx with sudo systemctl reload nginx.