With the shift to DevOps came a shift to continuous integration (CI) and continuous delivery (CD). Also known as CI/CD, it embodies the DevOps culture and operating principles. It was a natural progression in implementing agile frameworks and DevOps practices. Where once teams had to develop in separate phases and release in batches over long periods of time, they can now do it continuously with automation and constant feedback. Moreover, it decreases the need for long and tedious manual workflows with predictable and repeatable automated processes.
What Is CI/CD?
Continuous integration and delivery evolved in response to the need for faster and more reliable software — quickly becoming the standard for development. It emphasizes the importance of automation, collaboration, and continuous feedback for the reliable and quick delivery of high-quality code.
What Is CI?
CI is the practice of frequently integrating code changes from different developers into a shared code repository. Developers drop their code into the repo and automated tools and processes build and test the code to identify and fix any issues before they hit production. It reduces risk of errors, and improves the quality and stability of the codebase.
What Is CD?
CD is the next step in the pipeline, where changes are automatically deployed to production without the need of human intervention. This leads to faster, more frequent releases that reduces the time to value for end users.
Together, CI/CD helps address common challenges in development, such as long development cycles, high risk errors, and long lead times for new features. By automating from build to test to deployment, developers can focus on code and innovation instead of testing and troubleshooting.
How does continuous integration (CI) work?
CI improves collaboration and code quality through the frequent integration of code changes into a shared repo and automatic testing. The goal is to identify and resolve integration issues before they become more difficult and expensive to fix. Additionally, shorter commit cycles mean it’s less likely to have multiple developers editing the same code that requires a merge.
Many teams also use feature flags. The configuration mechanism allows teams to turn features and code on or off at runtime at the user, group, or environment level. Feature flags are usually conditional statements in the code that check the status of the flag and enable or disable the functionality accordingly. It makes it easy to keep features under development in the code, deployed in the main branch, and off until they’re ready to be used. Tools like LauchDarkly and Optimizely Rollout are great and integrate with CI/CD tools.
At a high level, the CI workflow goes something like this:
- Developers check code changes: Devs work on their code individually and then check them into the shared repository.
- Automated build: Once the code is checked in, an automated build process is triggered that pulls the latest code changes and compiles them to generate the app.
- Automated tests: After the build is complete, automated tests verify that the code changed doesn’t introduce any issues or break existing functionality of the app.
- Reports: The results are then reported back to the DevOps team. If there’s a failure, the team is notified immediately to remediate the issue.
- Integration: CI tools can be integrated with other DevOps tools like issue trackers, code review systems, and deployment systems.
How does continuous delivery (CD) work?
CD provides a rapid, reliable, and repeatable way to deliver software changes to users through automated building, testing, and deployment. Here’s how it works at a high level:
- Code changes are committed: Developers commit their code to a repo after they work on new features of bug fixes.
- Build process: The CD system automatically pulls the latest code changes and builds them into a deployable artifact, like a container image or compiled binary.
- Automated tests: The CD flow then runs automated tests to ensure that code changes are high quality and don’t negatively affect application performance.
- Deployment to staging: Once the code changes pass testing, the CD system deploys the changes into staging where more testing and validation happens.
- Manual testing: Sometimes manual testing is necessary to validate changes in staging.
- Deployment and monitoring: Once the changes are validated in staging, they’re deployed into production where they are monitored for any missed issues.
What are the benefits of CI/CD?
There are immediate benefits to enjoy for organizations that adopt CI/CD. For starters, happier users. Doing CI/CD properly means fewer bugs and issues negatively affect the end user experience. Time-to-value is also accelerated, as updates can be deployed at any time. Constant testing means less firefighting and smoother development cycles. Less bottlenecks and predictable deployment cycles in turn make it easy to hit dates and milestones. All this comes together to make developers more productive, freeing them to work on what matters, with less context switching and less frustration. Finally, recovering from issues is simplified with constant updates or rolling back changes.
What are some CI/CD tools and plugins?
CI/CD tools are typically very supportive of integrations and plugins to support third-party platforms, user interfaces, admin tool, Git repos, and more. It is important that when teams have selected their preferred CI/CD tools thet ensure that all environment variables are configured. Ultimately, they provide better capabilities, automation, and even observability.
What is the future of CI/CD tools?
CI/CD tools and workflows is already advanced greatly thanks to the help of machine learning and AI. MLOps is infrastructure-as-code (IaC) and CI/CD of machine learning models. Synthetic data generation is using machine learning to create data sets to be used in automated testing. AIOPs platforms are aggregating observability data and correlating alerts for disparate sources to trigger troubleshooting and remediation. We can expect CI/CD to continue to evolve and optimize development across industries and use cases.