Purpose

Ensure every Rails deployment is safe, reversible and verified.

Pre-Deployment

• All CI checks pass (RuboCop, Brakeman, bundler-audit, tests).
• Code coverage meets the project threshold.
• No pending migrations with dangerous operations.
• Migrations are reviewed by a second engineer.
• Strong migrations check passes.
• Gemfile.lock is up to date.
• Release notes are documented.
• Rollback plan is documented.
• Deployment window is communicated to the team.

Migration Safety

• All migrations are reversible.
• No columns added with a default value on large tables.
• Indexes on large tables use algorithm: :concurrently.
• Data backfills are in Rake tasks, not migrations.
• Column removals use the two-phase process (ignore → remove).
• Renames are handled with the addbackfilldrop pattern.

Deployment

• Migrations are run before application code deployment.
• Monitoring is active (error rates, response times, queue depth).
• Smoke tests pass after deployment.
• Background jobs are processing correctly.
• No unexpected error spikes.

Post-Deployment

• Deployment is recorded in the release log.
• Rollback plan is updated based on lessons learned.
• Monitoring continues for the next 24 hours.
• Team is notified of successful deployment.

Related Documents

• Rails Deployment Playbook
• Rails Engineering Handbook
• Rails Pull Request Checklist
• Rails Security Review Checklist