Continuous Integration (CI) and Continuous Delivery (CD) are fundamental practices for automating the development, testing, and deployment of applications. Docker integrates well with CI/CD tools, facilitating the implementation of automated pipelines to efficiently build, test, and deploy containers.

Introduction to CI/CD

Continuous Integration (CI) is a process that ensures code changes are regularly integrated and tested. Continuous Delivery (CD) allows these changes to be automatically deployed to production or testing environments, reducing development time and minimizing errors.

CI/CD Tools for Docker

There are multiple CI/CD tools that support Docker. Some of the most popular include:

• Jenkins: An extensible automation platform that allows integrating Docker to build and deploy images.
• GitLab CI/CD: Integrated tool in GitLab for creating pipelines and automating deployments.
• GitHub Actions: Offers workflows that enable automating CI/CD tasks directly from GitHub.

Create a Basic CI/CD Pipeline with Docker

Below is an example of configuring a CI/CD pipeline using a YAML file for GitLab CI/CD.

Example of a .gitlab-ci.yml File

This file defines a basic pipeline that builds a Docker image, runs tests, and deploys the image to an environment.

yaml

Automated Building and Testing with Docker

Automated testing ensures code quality before deployment. Docker facilitates running tests in containers, ensuring that the environment is consistent.

Example of Testing with Docker

To run tests inside a Docker container, include the necessary dependencies and scripts in the image.

dockerfile

Automated Container Deployment

In a CI/CD pipeline, the deployment stage ensures that approved changes are automatically deployed to the production or testing environment.

Example deployment command:

bash

Conclusion

Implementing CI/CD with Docker accelerates the development cycle and allows reliable and efficient continuous delivery. With automated build, test, and deployment pipelines, teams can release versions quickly and with quality. In the next chapter, we will explore Docker image registry and how to manage them in Docker Hub and other registries.