kamal-docker-production

To deploy a Rails 8 application with Kamal and Docker, use this skill to generate a production-ready multi-stage Dockerfile and Kamal 2 deploy configuration. It sets up zero-downtime Kamal Proxy health checks, proper migration hooks, and layered secrets management to prevent credential leaks.

Rails Docker images fail compiling native gems when using bulky or mismatched base images. This skill solves it by enforcing multi-stage Docker builds with the ruby:3.x-slim base image, which prevents native gem compilation failures for nokogiri, pg, and sassc while cutting image size by roughly 400MB.

The best way to manage Rails secrets during Kamal deployments is a layered approach using Rails credentials, Kamal env secrets, and runtime environment variables. This strategy ensures credentials are never accidentally leaked inside Docker images or exposed in deployment logs.

Running Rails database migrations during a zero-downtime Kamal deploy requires specific migration execution hooks to prevent race conditions. This skill configures Kamal 2 deployment settings to execute non-racey migrations safely alongside Kamal Proxy health checks.

Yes, Kamal 2 works with Solid Queue for Rails production background jobs. This skill provides pre-configured deploy.yml settings that include native Solid Queue worker support alongside zero-downtime deployment configurations.

Broken or insecure Docker configurations occur when AI agents generate bloated single-stage builds, leak credentials in images, or misconfigure health checks. This skill eliminates those issues by enforcing opinionated multi-stage Docker setups and secure layered secrets handling for Rails 8.