Just Add Code

So why not take this approach (where possible) with infrastructure? […] Need to upgrade? No problem. Build a new, upgraded system and throw the old one away. New app revision? Same thing. Build a server (or image) with a new revision and throw away the old ones.

— Chad Fowler, Immutable Infrastructure and Disposable Components

This builds a virtual server that accepts deployments via git push. It runs the Docker-powered mini-Heroku Dokku on a Hetzner Cloud project.

Getting started

Prerequisites

This is the software you need:

GNU Make
Terraform 0.12 or newer

Building the project

Once you have all required software, in the root directory of this project, run this command and follow the instructions:

$ make HOSTNAME=my.host.example.tld

What does this do?

asks for your Hetzner Cloud API token and stores it in terraform.tfvars
copies your public SSH key ~/.ssh/id_rsa.pub to the cloud project (so you can log in)
creates a server
installs dokku + dependencies on that server
installs the dokku-letsencrypt plugin

Customizing

With a file named cloud-init/secrets.sh, you can customize the creation of your dokku instance. That file is being ignored by git, use it to pass sensitive information like credentials for external services to your dokku instance.

Here's an example:

# secrets.sh
dokku apps:create node-js-sample
dokku config:set node-js-sample DATABASE_URL=zzz

Commands in secrets.sh will be executed as the very last step.

Removing everything

To remove all this, run:

$ terraform destroy