CI/CD - Security Software Glossary

What is CI/CD?

CI/CD stands for continuous integration (CI) and continuous delivery/ continuous deployment (CD). CI/CD automates the process of integrating code changes and deploying them to production environments, ensuring frequent, reliable updates with minimal manual intervention.

Continuous delivery takes this further by automating the process of preparing code for release, ensuring it's always in a deployable state. Continuous deployment, an advanced step, automates the release of code to production immediately after passing all tests, without human approval.

Summary

CI/CD is a core practice in DevOps that enables teams to integrate, test, and deploy code quickly and continuously. Continuous integration ensures that every code change is automatically integrated, built, and tested. It helps catch bugs early by triggering automated tests with every commit.

Continuous delivery is the automation of preparing code for release once it has passed all automated tests but requires manual approval before deploying to production. On the other hand, continuous deployment takes this automation a step further by automatically deploying code to production without manual intervention, making every change that passes tests live immediately.

CI/CD pipelines are crucial in modern software development, especially for teams adopting agile or DevOps methodologies. By automating the software delivery lifecycle, CI/CD reduces the time between writing code and deploying it to users, making it a critical tool for ensuring agility, reliability, and fast feedback.

Deep dive

Continuous integration (CI)

CI involves regularly merging code from multiple developers into a shared repository. After each commit, automated tests and builds run to ensure that the new code does not break the existing system. This prevents integration issues from snowballing, as code changes are smaller and easier to manage. CI tools like Jenkins, Travis CI, and GitLab CI are commonly used to automate the integration and testing process.

Continuous delivery (CD)

Continuous delivery extends CI by automating the preparation of code for release. Once the code passes all tests in the CI stage, it's automatically packaged and made ready for deployment to production. But unlike continuous deployment, the actual deployment requires manual approval. Docker and Kubernetes are popular tools in this stage for managing containers and orchestrating deployments.

Containers are lightweight, standalone software packages that include everything needed to run an app—code, runtime, libraries, and settings—ensuring consistency across different environments.

Continuous deployment (CD)

Continuous deployment takes automation further by pushing code to production as soon as it passes testing with no manual gatekeeping. This ensures the system can be updated continuously with minimal delay. It’s ideal for environments where rapid iteration and frequent updates are critical, like SaaS products. However, it requires mature automated testing and monitoring systems to ensure stability.

Examples

Netflix: Netflix uses CI/CD to manage and deploy hundreds of daily updates to its platform. By utilizing Spinnaker, an open-source CD platform, Netflix ensures that its infrastructure can handle frequent updates without service interruptions.
GitLab: As both a CI/CD tool and a user of CI/CD, GitLab delivers daily releases of new features and fixes using its own automated pipelines. The company uses CI/CD to streamline its internal processes and continuously improve its platform for customers.
Meta (Facebook): Meta employs CI/CD practices to deploy code continuously to its platform, allowing for hundreds of changes each day. By implementing a strong CI/CD pipeline, Meta maintains a smooth user experience while quickly iterating and fixing bugs.

History

CI/CD emerged from the agile movement in the early 2000s, focused on small and quick developments, continuous feedback, and cross-functional collaboration to quickly adapt to changing requirements. Agile helps teams deliver incremental changes to software, ensuring a responsive and flexible development process. As software projects grew in size and complexity, the teams realised they needed to integrate code frequently to avoid costly problems later. Martin Fowler was an early supporter of CI, highlighting the importance of automated builds and tests to ensure software stability.

In the late 2000s, Jenkins became one of the first popular CI tools, followed by the rise of containerization (via Docker) and cloud-based infrastructure, which led to the development of continuous delivery. This allowed companies to package their apps in a consistent, deployable format. With cloud platforms, companies like Netflix and Amazon pioneered the practice of continuous deployment, releasing updates to their infrastructure multiple times a day.

Future

As the software industry continues to evolve, CI/CD pipelines will incorporate artificial intelligence (AI) and machine learning (ML) to predict and optimize code deployments. AI-driven tools can help identify potential bottlenecks or security vulnerabilities earlier in the pipeline, making the process even more efficient. Security integration (or DevSecOps) is also becoming more essential as organizations focus on embedding security checks within the CI/CD process, ensuring that code is tested for vulnerabilities before it reaches production.

With the growth of microservices and serverless architectures, CI/CD pipelines are being adapted to manage these distributed environments. In the future, CI/CD will likely involve more real-time monitoring, automatic rollback features, and advanced failure detection mechanisms to maintain stability in increasingly complex software ecosystems.

Continuous integration and continuous delivery/deployment (CI/CD)