• CI/CD is a method to frequently deliver apps to customers by introducing automation into the stages of app development.
• A solution to the problems integrating new code can cause (a.k.a integration hell).
• Introduces ongoing automation and continuous monitoring throughout the lifecycle of apps, from integration and testing phases to delivery and deployment.
• These connected practices are often referred to as a CI/CD pipeline
• Supported by development and operations teams working together in an agile way.

CI = Continuous Integration

• A coding philosophy and set of practices to build automated tests and commit small changes frequently
• Each commit triggers an automated pipeline on a CI server, which can notify developers of any issues about integration.
• Merge changes back to the main branch as often as possible.
• Establish a consistent and automated way to build, package, and test applications.
• Automate tests to check that the application is not broken whenever new commits are integrated into the main branch.

CD = Continuous Delivery / Continuous Deployment

Continuous Delivery

• Automatically release to repository.

  • = A developer’s changes to an application are automatically bug tested and uploaded to a repository, where they can then be deployed to a live production environment by the operations team.
• Automated testing + automated release process = deploy app at anytime by clicking on a button.

Continuous Deployment

• Automatically deploy to production.
• One step further than continuous delivery
• Every change that passes all stages of production pipeline is released to customers.
• If test fails, new changes will not deployed.
• Can see changed code go live minutes after they're committed.
• Deploy with small batches continuously, so there isn't a Release Day anymore.

CI is part of CD. Continuous Deployment is like Continuous Delivery, except that releases happen automatically.