Continuous delivery - definition & overview

Continuous delivery is an ongoing DevOps practice of building, testing, and delivering improvements to software code and user environments with the help of automated tools. The key outcome of the continuous delivery (CD) paradigm is code that is always in a deployable state.

At its core, continuous delivery follows a streamlined process known as the continuous delivery pipeline for cloud computing environments. The pipeline begins with the developer or development team committing their code to the source repository. Automated tests (unit, regression, performance, etc.) are run for every check-in to ensure high-quality code. Once the code is verified, the executables are deployed automatically to an intermediate environment such as staging, integration, or UAT. At this point, the code is ready to go into production and can be pushed live on demand.

For continuous delivery to work effectively, fundamental principles should be in place. Of the many aspects of continuous delivery, the three significant pillars are continuous integration, configuration management, and test-driven development.

• Continuous integration ensures code worked by a developer across multiple locations is always integrated into a shared repository. This avoids the chaos that results from bulky and conflicting code commits.
• Configuration management makes it possible to abstract away the complexities of a product into simple configurations. It makes the software flexible, scalable, and lightweight.
• Test-driven development is what makes continuous delivery what it is. It ensures that the code can be tested and deployed, all in a matter of a few minutes. It has shifted the software delivery model from deployments scheduled across weeks or months to multiple releases in a single day.

These three terminologies—continuous integration, delivery, and deployment —indicate evolving maturity in software development practices in that order.

Continuous integration, the first step needed for this practice to work, refers to integrating individual code with the overall development environment after building and testing it. Tools like Jenkins ensure that the code is compiled, run, and tested before it's integrated with the rest.

Continuous delivery is the layer that sits on top of continuous integration. Continuous delivery, which only works if continuous integration is in place, involves running extensive regression, UI, and performance tests to ensure that the code is production-ready.

Continuous deployment takes the model a step further by automatically deploying code to production after each code commits and builds. While in continuous delivery, the deployment pipeline follows an on-demand model; it is pushed automatically every time. This can only work in highly mature DevOps teams. The so-called CICD pipeline (continuous integration/continuous deployment) is a practice focused on improving software delivery throughout the software development life cycle via deployment automation.

Higher quality products

Automated testing tools in a CD environment ensure maximum code coverage, so security, performance, integration, and other features of the code leave nothing to chance. This naturally leads to higher-quality products. Concepts like containerization eliminate ambiguities or minor differences in environments that could potentially cause unexpected production issues.

Quicker, less risky releases

Automated build and deployment and integrated tests ensure that manual processes involved earlier in pre-production deployments are now entirely removed. By eliminating last-minute surprises, production releases have become a routine job rather than a developer panic moment. This approach has helped teams achieve faster time-to-market with an increased number of releases than before.

More satisfied customers

Customers get the benefit of having features delivered faster with more accuracy. Using models such as blue-green deployment, DevOps teams can minimize downtime for customers during a production release, making it a seamless experience. Development teams can also collect constant feedback from users, making it easier to stay on the right track and remain aligned with customer needs.

More efficient and cost-effective DevOps teams

The culture of DevOps has transformed as development teams have assimilated QA functions. This means more effective and efficient coordination among groups, regardless of role. Also, by reducing operational complexities (build, test, and release), developers are free to focus on higher-quality problems, resulting in cost-effective teams that are higher on the motivation curve.

Sumo Logic enables CI/CD by giving development, QE, DevOps and SecOps teams a single pane of glass to measure and monitor KPIs or metrics developed by the DevOps Research and Assessment (DORA) organization for measuring the effectiveness of the software development and delivery process, and the ability to monitor and troubleshoot their pipelines and incident management processes by analyzing real-time data from various stages in CI/CD pipelines and DevOps tools. Learn more about Sumo Logic's Software Development Optimization Solution.

What role do automated tests play in continuous delivery?

Automated tests play a vital role in continuous delivery by ensuring that code changes are thoroughly tested and validated throughout development. For example, an automated test to help detect bugs, errors, and issues early on allows teams to address them promptly and maintain the stability and quality of the software. Development teams can run automated tests frequently and consistently, enabling rapid feedback on the impact of code changes and facilitating faster and more reliable software releases

What are some common tools used in continuous delivery pipelines?

• Jenkins

• GitLab CI/CD

• CircleCI

• Travis CI

• TeamCity

• Bamboo

• Azure DevOps

• Spinnaker

• Concourse

• GitHub Action