Mastodon is a free, open-source social network server based on ActivityPub.

The Mastodon server is implemented a rails app, which relies on postgres and redis. It uses sidekiq for background jobs, along with a separate nodejs http streaming server.

Docker images: https://hub.docker.com/r/tootsuite/mastodon/

Dockerfile: https://github.com/mastodon/mastodon/blob/main/Dockerfile

docker-compose.yml: https://github.com/mastodon/mastodon/blob/main/docker-compose.yml

Important notes:

• Ensure your fly.toml [env] section is fully populated before running any deploys of the application. mastodon will happily deploy with incorrect or invalid environment variables, which can break things later on [1].
• fly can automatically place your application in the optimal region for you, you can drop the --region flag and args if desired.
• You'll likely want to run this from a custom domain with SSL certificates, familiarize yourself with this guide: https://fly.io/docs/app-guides/custom-domains-with-fly/
• You'll want SMTP services enabled, sendgrid has a nice free tier, we'll use them in the [env] section of our fly.toml

$ fly apps create --region iad --name mastodon
$ fly scale memory 512 # rails needs more than 256mb

$ SECRET_KEY_BASE=$(docker run --rm -it tootsuite/mastodon:latest bin/rake secret)
$ OTP_SECRET=$(docker run --rm -it tootsuite/mastodon:latest bin/rake secret)
$ fly secrets set OTP_SECRET=$OTP_SECRET SECRET_KEY_BASE=$SECRET_KEY_BASE   

The VAPID Keys are requisite for the mastodon streaming API, they are generated in a way that doesn't play nicely with stdout, so you should surround them with quotations when setting as fly secrets.

$ docker run --rm -it tootsuite/mastodon:latest bin/rake mastodon:webpush:generate_vapid_key

The output of the previous command will look similar to this:

$ VAPID_PRIVATE_KEY=UWDTCtxJ-9QEXAMPLEz8TmKEYIVpYfhHOuOFI7ELvn0=
$ VAPID_PUBLIC_KEY=EXAMPLE_gzKiuO27vtpNVU3VgymkeyIKp5kbIiDmfkeyyhbkvYSxsu5s4eMeX-EXAMPLE=

Quote those values and set them as fly secrets:

$ fly secrets set VAPID_PRIVATE_KEY="UWDTCtxJ-9QEXAMPLEz8TmKEYIVpYfhHOuOFI7ELvn0=" VAPID_PUBLIC_KEY="EXAMPLE_gzKiuO27vtpNVU3VgymkeyIKp5kbIiDmfkeyyhbkvYSxsu5s4eMeX-EXAMPLE="

Redis is used to store the home/list feeds, along with the sidekiq queue information. The feeds can be regenerated using tootctl, so persistence is not strictly necessary.

$ fly apps create --region iad --name mastodon-redis
$ fly volumes create -c fly.redis.toml --region iad mastodon_redis
$ fly deploy --config fly.redis.toml --build-target redis-server

The fly.toml uses a [mounts] section to connect the /opt/mastodon/public/system folder to a persistent volume.

Create that volume below, or remove the [mounts] section and uncomment [env] > S3_ENABLED for S3 storage.

$ fly volumes create --region iad mastodon_uploads

Note: You will need an object storage bucket already made and S3 compatible API keys that can access it. (for this example we will use Cloudflare's R2 bucket)

1. Create an S3 Auth Token
2. Create Bucket
3. Configure Bucket to enable Domain Access
4. Optional: enable other cloudflare services as desired.

$ fly secrets set AWS_ACCESS_KEY_ID=xxx AWS_SECRET_ACCESS_KEY=yyy

See lib/tasks/mastodon.rake for how to change your [env] section for Wasabi, Minio or Google Cloud Storage.

$ fly pg create --region iad --name mastodon-pg
$ fly pg attach --postgres-app mastodon-pg

You may run fly deploy as many times as desired in the future. But ensure that it is ran the very first time with the proper [deploy] section in the fly.toml file commented out. (note the different release_commands and their descriptions.)

Run the initial database setup on first deploy, uncomment:

# [deploy]
#   release_command = "bundle exec rails db:setup"

Save the file, then run:

$ fly deploy

Validate your instance, create a user, confirm the email, setup MFA. Then proceed with the following if desired:

Comment previous section back out, then uncomment the admin creation commands.

# [deploy]
#   release_command = "tootctl accounts modify yourusernamehere --role admin"

Save the file again, then run:

$ fly deploy

You should now be finished, and have a newly created mastodon instance to administer as desired.