Optimizing for Free Hosting — Elixir Deployments

The article proposes a free-to-start deployment path for a Phoenix app on a single Google Cloud Compute Engine instance. It emphasizes low cost, full control, simple infrastructure, and zero-downtime releases without hot code upgrading, using built-in Linux tools instead of heavier deployment stacks.

Reading notes

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• The setup targets a free Google Cloud VM, with a static IP, DNS records, SSH access, swap space, Erlang, Elixir, Node, and Postgres installed manually.
• The author argues that simple server and deployment processes reduce downtime more than rare hardware failure does, as long as the database is backed up.
• Postgres is opened for remote access, with firewall and configuration changes so the database can be reached from a development machine.
• The app code is cloned from a Git repository, and secrets are copied to the server with scp.
• Nginx and Certbot are installed to provide SSL and reverse proxying to Phoenix.
• Zero-downtime deployment is achieved by starting a new release on the unused port while the old one still serves traffic, then reloading Nginx to switch over.
• A bash deploy script runs updates, tests, asset compilation, release creation, migrations, and port switching.
• systemd services keep the app running after crashes or reboots and route logs to journald.
• journalctl is used to follow logs, and journald is configured to limit log disk usage.
• The bonuses cover automated backups to another free instance and a rollback script for previous releases.