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CI vs. CD: The Evolution of Automation

CI and CD are both parts of DevOps automation, but they differ in both technology and processes.

CI/CD processes are frequently used together and often conflated. But they shouldn’t be. It’s important to understand the differences between CI vs. CD as you build and improve on your CI/CD pipeline.

CI refers to Continuous Integration and CD refers to Continuous Delivery or Continuous Deployment. Organizations may implement CI on its own to accelerate development, but it’s also the first step toward achieving CD. In short, CD is impossible unless you already have CI in place.

Let’s take a deeper look.

What is CI vs. CD?

Continuous Integration refers to integrating code into a mainline codebase in small, bite-sized chunks — including merging changes from multiple developers working simultaneously on the same codebase. Smaller commits ensure that issues are discovered faster and cause fewer disruptions. Achieving CI requires the right set of tools and policies.

Continuous Delivery involves streamlining testing, staging, and deploying code so that it can be deployed at will. It's more complex than CI alone, but this complexity allows organizations to develop more sophisticated release orchestration. CI generally leads into CD, but that isn’t always the case. CD requires a combination of the right technology and the right processes. Mature CD generally takes much longer than CI to achieve.

Continuous Deployment builds on Continuous Delivery to deploy all changes automatically into production. This makes it possible to swiftly push changes directly to users but introduces a lot of variability into the production environment. Many organizations opt for Continuous Delivery over Continuous Deployment or limit Continuous Deployment to specific use cases.

Why You Need CI and CD for Successful DevOps

Although it’s important to understand the differences between CI vs. CD, most organizations need both. CI is easier to achieve than CD and can be standalone; some developers still use their integrated development environment (IDE) and hand-coded Bash scripts for software delivery. However, CI alone cannot eliminate all the bottlenecks that impede successful DevOps implementations. Organizations must also adopt CD to unlock the full value of software delivery. 

CD: Continuous Delivery or Continuous Deployment?

You may hear both the terms Continuous Delivery and Continuous Deployment. As with CI/CD, these terms are used so interchangeably within the industry that their meaning can become muddled.

When someone refers to CD, they can be referring to either or both. The difference between the two comes down to the final stage of deployment.

  • Continuous Delivery. Software is automatically tested and packaged for deployment. Once the build is ready, it may be either manually or automatically deployed to the customer. This strikes the balance between speed and stability. Code is ready to be deployed at will, but there can still be strict control over what makes it into production.
  • Continuous Deployment. Every change that goes through the pipeline is automatically deployed directly to customers. This can be useful for hot fixes but is risky with more complicated changes.

The goal of most organizations is to be “deployment-ready” — able to deploy necessary changes to their system as quickly as possible. They can achieve this through more robust automation technology, including automated quality gates and better-automated testing.

Of course, many organizations will crawl before they walk and walk before they run. An iterative improvement process will strengthen an organization’s fundamental processes, technology and philosophy to reach fully automated, Continuous Deployment.

Automate Building, Testing, and Deployment Within the CI/CD Pipeline

Automation is central to the success of the CI/CD pipeline. When developers introduce new commits, the system automatically generates a build. The build is then run through a gauntlet of automated testing. Administrators get notifications if the build fails these tests. If it passes, the build progresses to the application servers. If the build breaks on the application servers, administrators are again made aware. At every stage of the CI/CD pipeline, automation and testing make speedy progression possible while also reducing the risk of defects making it into production.

Once fully realized, an organization’s CI/CD pipeline should provide fast, easy deployment at will. A developer should be able to commit a change and see that change in a deployable state within minutes. While reckless automation can hinder a system, the right automation helps organizations achieve the flexibility and consistency they need to truly benefit from DevOps.

When developers can integrate code automatically, collaboration improves. And by investing in test automation and quality gates, organizations can innovate faster, with less risk. 

CI/CD Processes Are Essential to DevOps

The bottom line: CI vs. CD is a useful distinction to prioritize new processes and tools, but CI and CD are both essential to successful DevOps. Although both are fundamental, each tackles a different stage of software development and offers different benefits. CI speeds up and improves the process of development. CD makes the process of deployment faster and easier.

Understanding the differences between Continuous Integration, Continuous Delivery, and Continuous Deployment can help establish and improve your CI/CD pipeline. Furthermore, assessing your CI/CD processes can help you identify where to intervene as your organization moves toward full automation and digital transformation.

Learn When to Focus on CI vs. CD

Optimizing CI and CD is an iterative process — your CI/CD pipeline will evolve with your business. Through Copado’s Five Steps to DevOps Success, organizations can understand when to focus on CI vs. CD to see the most value as they implement and refine their DevOps processes.