Kamal 1.0 released – a containerized deployment tool for Rails

Basecamp has officially released Kamal 1.0 (previously MRSK), solidifying it as a powerful and stable deployment tool for Ruby on Rails and other Dockerized web apps.

This 1.0 milestone marks Kamal as a production-ready, opinionated solution for zero-downtime deploys without relying on cloud-specific services or DevOps overhead.

What’s New in 1.0?

• Improved multi-host orchestration
• Tighter support for Docker Compose and health checks
• Native support for persistent volumes and secrets
• Rolling deploys with automatic cleanup
• Simplified rollback and restart mechanisms

Why Kamal over other tools?

1Tool         | Pros                                 | Cons
2-------------|--------------------------------------|-----------------------------
3Capistrano   | Time-tested, SSH-based               | No container support, slow
4Kubernetes   | Scalable, cloud-native               | Overkill for most Rails apps
5Heroku       | Super simple                         | Vendor lock-in, expensive
6Kamal        | Simple, Docker-native, zero-downtime | Self-hosting required

Kamal aims to strike the balance — giving you full control and performance without giving up simplicity.

Typical Deploy Flow

1. Configure config/deploy.yml
2. Build and push Docker image
3. Run kamal deploy
4. Kamal rolls out the new release without downtime
5. Rollback instantly if needed

1kamal deploy
2kamal rollback

Ideal For

• Rails and Dockerized apps
• Teams moving off Heroku or Render
• Self-hosted infrastructure
• Simple CI/CD pipelines

Resources

• Kamal GitHub Repo
• Kamal Docs
• Deploying Rails with Kamal Guide

Final Thoughts

With Kamal 1.0, deploying Rails apps with Docker is finally elegant, repeatable, and reliable. Whether you're building SaaS apps, APIs, or monoliths, Kamal makes self-hosted deploys frictionless and modern.