About CI/CD

CI/CD (Continuous Integration/Continuous Delivery) is the practice of automating the path from code to production. CI automatically builds and tests code on every commit. CD automatically deploys verified code to servers. The concept has been evolving since the 1990s and became the standard after the "Continuous Delivery" book (2010).

CI/CD is practiced by Netflix, Amazon, Google, Facebook, and Etsy. Amazon deploys every 11.6 seconds. Netflix deploys thousands of times per day. Etsy reduced its release cycle from weeks to hours after adopting CI/CD and automated testing.

A typical CI/CD pipeline: commit → build → unit tests → integration tests → staging deploy → acceptance tests → production deploy. Blue-green deployment switches traffic between two identical environments. Canary release routes a portion of traffic to the new version for validation.

Jenkins is the oldest and most flexible CI/CD server with thousands of plugins. GitLab CI is built into GitLab using YAML configuration. GitHub Actions integrates with GitHub and has a rich actions marketplace. ArgoCD implements a GitOps approach for Kubernetes. Terraform automates infrastructure creation (Infrastructure as Code).