Continuous integration (CI) and continuous delivery (CD) embody a culture, set of operating principles, and collection of practices that enable application development teams to deliver code changes more frequently and reliably. The implementation is also known as the CI/CD pipeline.

CI/CD is one of the best practices for devops teams to implement. It is also an agile methodology best practice, as it enables software development teams to focus on meeting business requirements, code quality, and security because deployment steps are automated.

A mature CI/CD devops practice has the option of implementing continuous deployment where application changes run through the CI/CD pipeline and passing builds are deployed directly to production environments. Teams practicing continuous delivery elect to deploy to production on a daily or even hourly schedule, though continuous delivery isn’t always optimal for every business application.

The technical goal of CI is to establish a consistent and automated way to build, package, and test applications. With consistency in the integration process in place, teams are more likely to commit code changes more frequently, which leads to better collaboration and software quality.

CI/CD tools help store the environment-specific parameters that must be packaged with each delivery. CI/CD automation then performs any necessary service calls to web servers, databases, and other services that may need to be restarted or follow other procedures when applications are deployed.

Continuous integration and continuous delivery require continuous testing because the objective is to deliver quality applications and code to users. Continuous testing is often implemented as a set of automated regression, performance, and other tests that are executed in the CI/CD pipeline.

Sophisticated CI/CD Pipeline.

Continuous delivery is the automation that pushes applications to delivery environments. Most development teams typically have one or more development and testing environments where application changes are staged for testing and review. A CI/CD tool such as Jenkins, CircleCI, AWS CodeBuild, Azure DevOps, or Travis CI is used to automate the steps and provide reporting.

More sophisticated CD may have other steps such as performing data synchronizations, archiving information resources, or performing application and library patching. CI/CD tools typically support a marketplace of plug-ins.

CD tools also provide dashboard and reporting functions. If builds or deliveries fail, they alert developers with information on the failures. They integrate with version control and agile tools, so they can be used to look up what code changes and user stories made up a build.

Teams need to develop consensus on the right approaches for their business and technologies so that once CI/CD is in place the team is onboard with following practices consistently.