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CICD Concepts

Challenges with Manual Deployment

Merge Conflicts

Multiple developers pushing simultaneously can overwrite each other’s code.

Human Errors

Mistakes such as deploying to the wrong server, using the wrong branch, or missing files during deployment can occur.

Production Issues

Manual deployments can lead to downtime or broken features if bugs are introduced.

Rollback Difficulty

Reverting a failed deployment manually is time-consuming and error-prone.

“It Works on My Machine” Problem

Code may function locally but fail in other environments due to:

  • Differences in OS, libraries, or versions
  • Mismatched environment variables or configuration
  • Missing dependencies

This often results in production bugs and wasted debugging time.

Manual Deployment Frequency

For a small team (e.g., 5 developers), safe manual deployment is typically limited to 1–2 times per day.

Continuous Integration

  • Developers push the code to a code repository often (e.g., GitHub, CodeCommit, Bitbucket…)

  • A testing/build server checks the code as soon as it’s pushed (CodeBuild, Jenkins CI, CircleCI, Travis CI...)

  • The developer gets feedback about the tests and checks that have passed/failed

  • Find bugs early, then fix bugs

  • Deliver faster as the code is tested

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Continuous Delivery

  • UI and application-specific artifacts are made available on web servers

  • Ensures that the software can be released reliably whenever needed

  • Ensures deployments happen often and are quick

  • Shift away from “one release every 3 months” to “5 releases a day”

  • Usually involves automated deployment (e.g., CodeDeploy, Jenkins CD, Spinnaker...)

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Continuous Deployment

  • Every change that passes automated tests is automatically deployed to production
  • Eliminates manual intervention for deployment
  • Provides rapid feedback from production environment
  • Reduces risk by deploying smaller changes frequently
  • Enables faster innovation and quicker response to customer needs
  • Requires robust automated testing and monitoring to ensure stability

Continuous Delivery & Continuos Deployment

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CI/CD Workflow

  1. Code Commit: Developers commit code changes to the version control system (e.g., Git).
  2. Continuous Integration (CI): The CI server detects code changes and triggers the build process. The code is built and packaged into deployable artifacts.
  3. Automated Testing: Automated tests (unit, integration, functional) validate the code to ensure it meets quality standards and does not introduce new issues.
  4. Artifact Management: Successful builds are stored in an artifact repository. Artifacts are versioned and managed for deployment.
  5. Deployment: The application is deployed to a staging environment for additional testing (UAT, performance testing). Once staging tests pass, the application is deployed to production.
  6. Monitoring and Logging: Monitor application performance, availability, and health in production. Collect and analyze logs for troubleshooting and insights.
  7. Feedback and Alerts: Track issues and set up alerts for any problems during or after deployment. Gather feedback from monitoring and users.
  8. Rollback: If a deployment causes issues, revert to a previous stable version to address critical problems promptly.
  9. Continuous Improvement: Conduct retrospectives to review the CI/CD process and implement improvements based on feedback and lessons learned.

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CI/CD Tools

Category Tools
Source Code Repository GitHub, Bitbucket, GitLab, CodeCommit
CI Servers Jenkins, CircleCI, Travis CI, GitHub Actions, CodeBuild
CD / Deployment Jenkins CD, CodeDeploy, Spinnaker, Octopus Deploy
Containerization / Orchestration Docker, Kubernetes, Amazon ECS
Monitoring / Feedback Prometheus, Grafana, ELK Stack, CloudWatch