mastodon/docs/Running-Mastodon/Heroku-guide.md

Heroku guide

Mastodon can be run on a free Heroku app. It should be noted this has limited testing and could have unpredictable results.

Basic setup

Click the button above to start creating a Heroku app with the Mastodon repo as the source. This tells Heroku to use the app.json file which does things like prompt for config variables, set up the right buildpacks, run a postdeploy task, and add the appropriate addons.

If you don't use the deploy button and app.json approach, you will need to do some of that manually.

Domain names and SSL

You can add your domain name to the Heroku app's setting, and then also use Heroku's (free) auto renewal program for Lets Encrypt certificates, by requesting a cert from the settings screen. You'll have to point your hostname DNS at Heroku using the values heroku gives you on this screen, using whatever method is appropriate for your DNS setup.

You should set the Heroku config vars of LOCAL_DOMAIN to your hostname, and LOCAL_HTTPS to "true" as well.

Email

Consider using Mailgun or similar, who offer free plans that should suit your interests. Look in production.rb to see which config variables need to be set on Heroku for outgoing email to work.

File storage

You will want Amazon S3 for file storage. The only exception is for development purposes, where you may not care if files are not saved. Follow a guide online for creating a free Amazon S3 bucket and Access Key, then enter the details.

If you deploy from the web, the format for all the S3 bits use Paperclip conventions:

S3 Bucket is just the name of the bucket, e.g. bucketname not the full ARN.

S3 Region is the AWS code for the region e.g. ap-northeast-1 not the name of the city displayed on the AWS Dashboard.

To protect the privacy of the users of the your instance, you should have permissons on the your S3 bucket set to no-read and no-write for the public and non-application-specific AWS users, with only one authorized IAM user or group set up to be able to upload or display content. This is an example of an IAM policy used for the S3 bucket used Mastadon instance hentai.loan:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Effect": "Allow",
            "Action": [
                "s3:ListAllMyBuckets"
            ],
            "Resource": [
                "arn:aws:s3:::*"
            ]
        },
        {
            "Effect": "Allow",
            "Action": [
                "s3:*"
            ],
            "Resource": [
                "arn:aws:s3:::hentailoan”,
                "arn:aws:s3:::hentailoan/*"
            ]
        }
    ]
}

Deployment

You can deploy from the Heroku web interface or from the command line. Run:

heroku run rails db:migrate

after you first deploy to set up the first database.

You may need to use the heroku CLI application to run:

USERNAME=yourUsername rails mastodon:make_admin

to make yourself an admin.