Continuous Integration, Delivery and Deployment

CI/CD Systems are used to speed up development and delivery.

The terms explained

• Continuous Integration
• Continuous Delivery

• Continuous Deployment

• Image for clarity

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"If any developer in your team can stop what they’re doing right now and ship the current development version of code to production in 20 minutes or less without anyone stressing about what could happen — congratulations, you’re doing CI/CD!"

Basic steps in a CI/CD Pipeline

Basic steps: Build - Test - Deploy Staging - Deploy Production
If using Docker and Kubernetes: Build - Test - Dockerize - Deploy to Kubernetes - Tag latest docker

Tools for CI/CD

Requirements for CI/CD

• Parallel computing systems for parallel tests etc.

Implementation

• CI
  • Build Stage
    • Code changes need to be compiled
    • These days there is a need to pack them in Docker containers
    • Automated Tests verify specific units of code like UI behaviour, API reliability, performance, etc.
    • Maintain test reports
  • Testing Stage
• CD
  • Deployment Stage
    • Deployment Methods
      • Canary Deployment
      • Blue Green Deployment

Tips for building a CI-CD pipeline

• Follow DevOps practices

Architecture

• Architect in a way that supports iterative releases - Avoid tight coupling between components
  • Implement metrics that help detect issues in realtime (?)
• Developers should be able to deploy to staging for QA/manual testing
• All deployments should only involve the click of a button

Testing

• Run fast and fundamental tests first
• Always use same environment for testing

Triggers

• Include PRs, but Peer Review each PR
• In CD - Auto Deploy PRs merged to master

Improvement Tips

• Document flaky tests and improve them
• Optimize Feedback loop
  • Invest in a CI/CD that can run tests in parallel stages.
  • Improve slow tests