Continuous Deployment (CD)

Continuous Deployment (CD) is a software release practice where every code change that passes automated tests is automatically deployed to production. It extends Continuous Integration (CI) by ensuring that validated changes are delivered to users quickly and reliably — without manual intervention.

Core Concepts

1. Automation of the Deployment Pipeline
   Every stage — build, test, and deployment — is automated to eliminate manual steps and reduce human error.

2. Comprehensive Testing
   Automated tests (unit, integration, end-to-end) ensure that only stable and verified code reaches production.

3. Continuous Delivery vs. Continuous Deployment

   • Continuous Delivery: Code is ready for release at any time but requires a manual approval to deploy.
   • Continuous Deployment: Every approved change is automatically released to production.

4. Monitoring and Rollback
   Automated monitoring detects issues post-deployment, and rollback mechanisms ensure quick recovery if problems arise.

5. Incremental Releases
   Features are deployed in small batches, reducing risk and making troubleshooting easier.

6. CD Tools
   Tools like GitHub Actions, GitLab CI/CD, Jenkins, Argo CD, and Spinnaker manage deployment workflows and environments.

In essence: Continuous Deployment enables fast, reliable, and automated delivery of software to users — turning every passing build into a production release.