CI and CD stand for continuous integration and continuous delivery/continuous deployment. In very simple terms, CI is a modern software development practice in which incremental code changes are made frequently and reliably. Automated build-and-test steps triggered by CI ensure that code changes being merged into the repository are reliable. The code is then delivered quickly and seamlessly as a part of the CD process. In the software world, the CI/CD pipeline refers to the automation that enables incremental code changes from developers’ desktops to be delivered quickly and reliably to production.
Why is CI/CD important?
CI/CD allows organizations to ship software quickly and efficiently. CI/CD facilitates an effective process for getting products to market faster than ever before, continuously delivering code into production, and ensuring an ongoing flow of new features and bug fixes via the most efficient delivery method.
What is the difference between CI and CD?
Continuous integration (CI) is practice that involves developers making small changes and checks to their code. Due to the scale of requirements and the number of steps involved, this process is automated to ensure that teams can build, test, and package their applications in a reliable and repeatable way. CI helps streamline code changes, thereby increasing time for developers to make changes and contribute to improved software.
Continuous delivery (CD) is the automated delivery of completed code to environments like testing and development. CD provides an automated and consistent way for code to be delivered to these environments.
Continuous deployment is the next step of continuous delivery. Every change that passes the automated tests is automatically placed in production, resulting in many production deployments.
Continuous deployment should be the goal of most companies that are not constrained by regulatory or other requirements.
In short, CI is a set of practices performed as developers are writing code, and CD is a set of practices performed after the code is completed.
Benefits of CI/CD
There are many benefits of implementing CI/CD into your software development lifecycle. Let’s take a look at some of them:
Increased speed: With an automated CI/CD pipeline, teams can ship changes every hour, day, week, month, etc., and we can optimize each stage of the process. New changes and features can be launched quickly, which allows you to respond to new trends and address any issues that come up.
Easy maintenance: When it’s time to perform routine maintenance, you don’t want all of the system to shut down at once. To address this problem, you can create microservices in the architecture of your code so that individual areas of the system are taken down for maintenance instead of the entire system.
Improved collaboration and visibility: A CI/CD pipeline allows many people to get involved in the process, which promotes visibility and collaboration across different teams and orgs.
Real-time feedback: Shipping regular updates allows you to receive more immediate feedback from users. It also allows you to experiment with different features and fixes, and then hear about their performance shortly after deployment.
Continuous reliability and continuous testing: Continuous reliability, or test reliability, improves in a CI/CD pipeline. This is because incremental changes are implemented one at a time, which allows for more precise and accurate tests to be conducted continuously.
High-quality code: With CI/CD, your code is tested regularly. This means that you’ll discover bugs sooner and fix them more quickly.
CI/CD tools
A good CI/CD tool can help you create a strong CI/CD pipeline. Popular CI/CD tools include:
Jenkins: Jenkins is an open-source, Java-based automation server that supports building, deploying, and automating software development processes.
CircleCI: CircleCI supports software development and publishing. It allows you to automate the entire pipeline, and integrate with services like GitHub, GitHub Enterprise, and Bitbucket to perform builds when code is committed.
GitLab: GitLab provides a suite of tools for managing the software development lifecycle. You can perform builds, run tests, and deploy code. It also allows you to build jobs in a VM, Docker container, or a different server.
Major cloud providers, such as Microsoft, Amazon, and Google, also offer CI/CD process tools:
Azure DevOps: Azure DevOps provides a variety of CI/CD tools, like Git repo management, testing, reporting, and more. It provides support for Azure, Kubernetes, and VM-based resources.
AWS CodePipeline: AWS CodePipeline is a continuous delivery service that allows you to automate release pipelines. It easily integrates with third-party services like GitHub.
Cloud Build from Google Cloud Platform (GCP): Cloud Build from GCP is a serverless CI/CD platform that allows you to build software across all languages, such as Java and Go, deploy across multiple environments, and access cloud-hosted CI/CD workflows within your own private network.
A typical CI/CD pipeline can be broken down into the following stages:
•Development. This stage is where the development happens, and the code is merged to a version control repository and validated.
•Build. The application is built using the validated code, and this artifact is used for testing.
•Testing. Usually, the built artifact is deployed to a test environment, and extensive tests are carried out to ensure the functionality of the application.
•Deploy. This is the final stage of the pipeline, where the tested application is deployed to the production environment.
Conclusion
Today, we’re shifting responsibilities and goals to the left to ensure issues are caught early on in the software delivery process. CI and CD work together to ensure we have the capabilities and visibility to catch and fix defects and potential production failures or incidents that can be otherwise detrimental to a business. CI/CD pipelines act as automated delivery pipelines, mimicking the entire software development life cycle (SDLC) that otherwise can be hard to understand, improve, share, and control.