What is CI/CD?
CI refers to Continuous Integration, and CD stands for Continuous Delivery, Continuous Deployment, or both. The CI/CD is a method that automates software updates at all stages of the software development lifecycle (SDLC) and continuously delivers code fixes and new versions of the application without requiring user intervention.
Continuous Integration refers to the periodic process of building, testing, and merging new features to the app’s backend repository, such as GitHub. On the other hand, Continuous Delivery refers to the inclusion of automated testing and uploading to the repository. Furthermore, Continuous Deployment refers to the automatic deployment of new changes in the repository to the end-user application.
Continuous Delivery and Continuous Deployment might be used in different contexts, but they refer to the degree of automation involved in the software development lifecycle. Numerous CI/CD solutions are available on the market. Some of the most prominent ones are GitLab, Jenkins, CircleCI and Buddy.
How Kubernetes Works with CI/CD Solutions
Kubernetes is a cloud-native containerization framework that enables organizations to deploy in clusters. It allows you to deploy, scale, and manage your applications with ease.
Kubernetes can help automate the entire CI/CD process, from code commit to production deployment. It provides a reliable and scalable platform for running applications and makes it easy to roll out updates and fix problems quickly.
Code Push to Version Control System
Programmers can write new application code or make changes to the existing code and push it to the version control system. The Git platform provides this type of version control using a repository that can be accessed by multiple programmers and administrators working together on the same project.
Build and Test
Once the code is updated on the version control system, it automatically triggers the build and test phase with the help of CI/CD solutions such as GitLab or Jenkins. The tool builds a container image and tests it. After the code passes a set of tests that check for errors and operability, the container image is pushed to the Kubernetes infrastructure.
Deploying Containers to Docker and Containerized Apps
Kubernetes receives the image and deploys it to Docker, which acts as an intermediary between Kubernetes and the containerized applications. Docker offers a de-facto common standard that can work across applications. So when Docker receives the image, it modifies the information making sure it conforms to the common standard and then deploys it to the containerized apps on the Kubernetes clusters.
Tools for CI/CD
GitLab is one of the most popular CI/CD solutions which offers end-to-end capabilities for any DevOps project. It has a number of valuable features for managing the software development lifecycle. GitLab helps improve developer productivity with in-context testing results and provides additional guardrails to safeguard deployments.
GitHub Actions is a CI/CD solution that enables engineers to automate end-to-end DevOps operations, so they are performed every time code is pushed into the Git repository. Thus, building, testing, and deployment stages occur automatically every time new code arrives at the common repository.
Jenkins is a CI/CD tool like GitLab and is yet another go-to option for organizations. However, it doesn’t provide the end-to-end DevOps operational capabilities of the former. The tool provides an efficient way to integrate the CI/CD pipeline into the Kubernetes infrastructure and has multiple plugins, which GitLab doesn’t.
ArgoCD provides Continuous Delivery/Continuous Deployment capabilities but doesn’t have a built-in CI (Continuous Integration) capability. If an organization leverages ArgoCD, it still requires another tool for implementing the CI operations. Although Jenkins is a complete CI/CD tool, ArgoCD can be integrated with the former and used for managing apps.
CircleCI is a complete CI/CD tool that solves several challenges of Jenkins, including a slow UI, lack of information exchange between Git and Jenkins servers, and requirement for a dedicated server. While Jenkins is more secure, CircleCI is lighter and offers optimized operational capabilities.
Besides these, there are several other CI/CD solutions, such as Spinnaker, GoCD, FluxCD, Buddy, and more.
Best Practices for Kubernetes CI/CD
Integration with Git-Based Workflows
GitLab and GitHub Actions enable engineers to push code to a repository before being deployed to the containerized apps. Thus, engineers can perform quality and security checks on the code before deployment. Furthermore, GitLab provides end-to-end DevOps operations, which means engineers can access all capabilities on one platform.
Usage of Blue-Green Deployment Patterns
Blue-green deployment is a technique for rolling out updates to a software application in a way that minimizes downtime and risk. It involves creating two copies of the application. The blue version is the live version of the application that users are currently accessing, while the green version is the updated version that is being prepared for deployment.
Test and Scan Container Images
With CI, testing and scanning container images become simpler. Engineers should leverage the feature to check all container images for errors and issues before deploying them to the application cluster.
Benefits of CI/CD
- Improved quality: CI/CD pipelines enforce the Shift Left approach, and testing for quality and security takes place earlier. As a result, the vulnerabilities and other issues are caught earlier and solved before deployment, leading to a low defect rate.
- Faster Product Delivery: Instead of manually testing and reviewing every new version of the app, the CI/CD pipeline automates the process leading to a shorter time between the coding and the deployment stages.
- Optimized Testing and Monitoring: As with the low defect rate, the Shift Left approach optimizes the testing and monitoring process. Furthermore, it helps monitor the performance of the app's new versions in real-time and simplifies the troubleshooting process.
- Greater agility: CI/CD allows teams to be more agile and responsive to change, as it makes it easier to experiment with new ideas and quickly incorporate feedback.
- Measured Progress: CI/CD pipelines from solutions such as GitLab enable any company to measure the DORA (DevOps Research and Assessment) metrics. With this, they can measure parameters such as lead time for a change, change failure rate, and more that determine the efficiency and quality of the DevOps lifecycle. The parameters help a company identify gaps in the pipeline and fix them.