Continuous integration (CI) and continuous delivery (CD) in details
The ability to build and deploy safely into production crosses several disciplines, and the major ones are Continuous Integration (CI) and Continuous Delivery (CD). These are the best practices for DevOps teams. They establish ongoing automation across the whole lifecycle of apps.
CI/CD is a set of practices. It facilitates the latest code merges into the master branch and ensures various testing at each stage. In other words, CI/CD is a solution to the “integration hell” for development and operations teams. How does it work? Keep on reading to find out.
Continuous integration is about consistently integrating software development changes. It requires a version control system like Git to track alterations. Developers merge code changes to the master branch as often as possible. If there’s a conflict between new and existing code, automated testing helps to fix those bugs quickly and often. Using CI allows you to avoid integration challenges and don’t wait for release day to merge your piece of work.
Successful CI means new code changes are regularly built, tested, and merged to a shared repository. The goal of CI is to produce an object ready to be deployed onto a server or a machine. It can be a container image, WAR/JAR file, or any other executable packaged code.
Following the builds automation and integration testing, continuous delivery automates the entire release process of the validated code. So, to have an effective CD process, you must include CI into your development pipeline.
Continuous delivery is related to operations teams and workflows. CD responsibilities can include provisioning infrastructure, ticket management, deploying objects, verifying and monitoring those changes. The goal of continuous delivery is to deliver a packaged piece of code into a production environment at any time by just clicking a button.
Speaking of CD, you can sometimes hear the continuous deployment term. It’s the other possible CD, which refers to automatically releasing changes from the repository to production. It addresses the problem of overcharging operations teams with manual processes that slow down app delivery.
How CI and CD work together
Continuous integration establishes the smooth process of building, packaging, and testing apps. CD starts where CI ends. Continuous delivery automates the delivery of apps to infrastructure environments.
CI/CD combination ensures you have the capabilities to catch and fix defects that can harm a business. Altogether, these practices represent a CI/CD pipeline. Development and operations teams work side by side and apply either DevOps or SRE approach to support those pipelines.
CI/CD practices describe successful deployment process taking into account three major principles:
- Split Responsibility
It’s about just-in-time involvement from various team members. For example, developers and designers create features that work, proving it works through unit tests. Quality engineers (QEs) are responsible for features review and maintaining product quality. Product owners (POs) coordinate results from user acceptance tests. They validate past user stories and form new ones to improve user experience.
- Reduce Risk
Associate any risk with each team’s responsibility to diminish its total amount. Remember that every stage should serve as a gateway for quality control. Developers minimize broken logic, QEs ensure user flow integrity, POs cut down the number of unusable features, and so on.
- Decrease Feedback Loop
Use machines for particular actions because humans don’t scale — machines do. Setting up a CI/CD pipeline shortens the feedback time. And scaling allows you to automate the deployment process (it takes much longer for a person).
If your company practices CI/CD, it will have a competitive advantage and will bring you a wide range of benefits, like:
- Fewer bugs in production (automated tests capture all regressions early).
- Building the release is easy (all integration issues have been solved).
- Less distraction for developers (alerts appear immediately).
- QEs spend less time testing and can focus on significant quality improvements.
- Testing costs are dramatically reduced (CI server can run hundreds of tests in a moment).
- Smooth software deploys.
- Frequent releases.
- Much less pressure on decisions for small changes (faster development pace).
The CI/CD pipelines act as automated delivery pipelines. Their structure is unique for each team. It follows the project needs and goals (deployment to multiple environments, test orchestration, using several services in parallel).
In particular, if your app has serverless pieces, it’s better to deploy longer-running workloads to Kubernetes and the serverless ones to a cloud provider. CI/CD allows you to maintain context and configuration across the pipeline and achieve the goal of deploying to multiple pieces of infrastructure across stages.
Typical pipeline elements will include tools or processes that involve:
- Building code
- Release strategies
- Vulnerability checking
If you’re just getting started on a new project with no users yet, it might be easy to set up the CI/CD pipeline. You automate the alpha version, improve your testing culture and make sure that you increase code coverage as you build your app. By the time you’re ready to onboard users, you will have a reliable delivery process with automated testing before the production release.
But in case you already have an existing app with customers, consider step-by-step improvement. Start by implementing basic unit tests. There’s no need to focus yet on the complex end-to-end testing. Automate your delivery as soon as possible, and only then improve tests.
Are there any cases when CI/CD may not be suitable? Well, yes.
- Your customers don’t want continuous updates to their systems.
- Regulations restrict software update conditions. In particular, continuous updates of software used in aerospace, telecom, and medical industries is not an option.
In brief, organizations should be aware of CI/CD practices. Building a high-quality pipeline is about making it fast, safe, and stable. If the code doesn’t reach production in an hour, or if more than 2 out of 10 deployments fail, you’d better reconsider your CI/CD pipeline design and strategy.
Continuous integration and delivery tools help store the environment-specific parameters. CI/CD automation then performs any necessary service calls to web servers, databases, and others.
Modern solutions serve different purposes. Travis CI, CircleCI, AWS CodeBuild, Jenkins, or Atlassian Bamboo ease automation and provide reporting. Bitbucket Pipelines significantly reduces costs to adopt CI/CD practices. GitLab CI integrates your team’s code in a shared repository.
Indeed, any tool that’s foundational to DevOps is likely to be part of a CI/CD process. Configuration automation (Ansible, Chef, Puppet), container runtimes (Docker, CRI-O), and container orchestration (Kubernetes) solutions aren’t strictly CI/CD tools, but they’ll show up in many workflows.
CI/CD practices certainly enable companies to upgrade products frequently and securely. They are essential to software development using Agile methodologies. CI/CD pipelines remarkably facilitate the release process and improve user experience.
Still, establishing CI/CD can be tricky. To avoid failures and overloading, we highly recommend you entrust this task to professionals. Consider only reliable teams with proven experience. If you need an audit or consulting, contact us: firstname.lastname@example.org