Continuous Integration (CI) and Continuous Deployment (CD) are the most sought-after technologies and tools for having agile IT. In the past, developers would automate their build process using any one of the build tools. Then they would hand over their code to the operation team to proceed with deployment, administration, management, and support. There are many configuration management and software deployment tools in order to automate the tedious and tough affair of software deployment and delivery. This segregated pattern brought forth a number of recurring issues. With containers, the operation team could build standard container images of the full stack that they want to deploy and deliver. Developers can use them to deploy their code to do unit testing. That same tested, refined, and hardened image can be used across all environments (development, test, stage, and production) to get the same results every time. This containerization-sponsored setup specifically accelerates the software deployment and delivery activities in a risk-free fashion.

As per the Docker site, CI/CD typically merges development with testing, allowing developers to build code collaboratively, submit it to the master branch, and check for any issues. This means that developers can build and test their code to catch bugs early in the applications development life cycle. Since Docker can integrate with tools such as Jenkins and GitHub, developers can submit code in GitHub, test the code, and automatically trigger a build using Jenkins, and once the image is complete, it can be added to Docker registries. This ultimately streamlines the process and saves times on build and setup processes, all while allowing developers to run tests in parallel and automate them so that they can continue to work on other projects while tests are being run. The environment dependencies and inconsistencies get eliminated with the containerization.