Using Kamal 2.0 in Production

Source: fly.io Date: 2025-06-09 URL: https://fly.io/blog/kamal-in-production/

Summary

Educational essay by Sam Ruby documenting a comprehensive guide to deploying real-world Rails 8 applications with Kamal 2.0, extracted from “Agile Web Development with Rails 8.” The guide addresses a gap in existing Kamal documentation: the seven things you actually need to get started (Docker, container registries, secret management, load balancing, databases, backups, logging, monitoring, security) are never synthesized in one place.

Implications

Competition with Vercel/Render thread. Kamal 2.0 is the Rails community’s self-hosting answer to managed PaaS platforms. By publishing this on fly.io’s blog, Fly signals alignment with the self-hosting ethos while also positioning their platform as the natural destination for Kamal-deployed apps. The overlap is real: Kamal deploys to any Docker host, including Fly Machines. This is soft competition with Render and Railway, which compete for the “Rails team that doesn’t want to manage Kubernetes” market. The AI-assisted documentation angle (Copilot for XML-to-Markdown conversion) is a minor but notable signal of AI tooling entering technical writing workflows.