In recent years, Kubernetes has become a standard for container orchestration in the cloud-native world. Its scalable and extensible architecture deploys application containers that provide an ideal platform for developers to quickly deploy new features continuously through Continuous Integration (CI) and Continuous Delivery (CD) (or CI/CD).

CI/CD is a critical component of DevOps and software testing. Nowadays, every software implements a proper CI/CD pipeline to detect bugs and avoid integration issues. CI/CD pipelines in Kubernetes streamline the development and deployment phases by deploying instances of a CI/CD container.

A CI/CD container observes the code version control system for any changes pushed onto the repository and run pipeline steps. Once the tests defined in the pipeline are completed successfully, code changes/new features are deployed into production environments.

It’s important to understand that CI/CD operations comprise various code triggers depending upon the project requirements, and Kubernetes makes these operations manageable by deploying various CI/CD tools that run continuous integration and deployment processes using custom tasks or plugins.

The landscape for CI/CD tools is vast and growing; with so many options out there, choosing the right one that suits the budget can be tricky. That’s why in this blog, we’ve put together a CI/CD guide to simplify the development and DevOps process.

The guide divides into three parts: In the first part, we will discuss the benefits of CI/CD for Kubernetes. Then, we will have a look at the best CI/CD tools for Kubernetes. Lastly, we will cover the best Kubernetes CI/CD practices.

Let’s get started with the benefits.

No Manual Kubernetes Deployments

Deploying and starting a Kubernetes cluster is an effortless and straightforward task nowadays, but allowing new updates and features to run the Kubernetes cluster manually is not straightforward because of complex YAML configurations and resource types.

In these contexts, CI/CD provides a continuous delivery pipeline to Kubernetes that will automate these workflows without having the teams deploy these changes manually.

Almost everything related to deployments, whether they are resources, secrets, and version history, are kept under source control and use automated testing and integration services to make Kubernetes deployments seamless and error-free.

Rolling Out New Versions Safely

CI/CD supports various deployment and testing patterns, which offers the flexibility to safely deploy and test applications, significantly reducing, or in some cases, even eliminating the downtime.

For instance, Blue-Green deployments allow the running of identical instances in parallel for testing and production uses, making a copy of the release always available to developers to roll back to the previous version or quickly testing applications.

Testing patterns like Canary testing ensures when a new version rolls out for testing purposes. It is initially available to a small subset of traffic to quickly execute validation tests. Canary testing happens through two identical instances from which one instance handles all the traffic while the other handles a trusted subset of traffic.

CI/CD tools for Kubernetes

Jenkins

Jenkins is one of the most popular open-source CI/CD platforms used by thousands of enterprises worldwide to achieve continuous integration and build automation. Written in Java, Jenkins provides various versions, plugins, and features for testing, deploying, and building a project.

For instance, Jenkins X, a new iteration of Jenkins, is built specifically to support cloud-native applications on Kubernetes. Jenkins-X allows developers to quickly deploy new Kubernetes projects using features like Automated CI/CD, Preview Environments, and GitOps.

With Jenkins X, it is easier to make continuous changes through its concept of Environments. In Jenkins X, Environments isolate resources for individual teams and namespaces, providing flexibility for adding new features merged into the main branch after automated testing.

Installing and using Jenkins X is done through an extensible plugin system that eases the learning curve by automating the deployment of CI/CD pipelines through a wide variety of testing and deployment strategies. For using Jenkins with Kubernetes, developers have to install the official plugin, which is done through the Java environment, available to use with different platforms like Windows, macOS, Ubuntu, and RedHat.

Spinnaker

Spinnaker is a Netflix-backed open source CI/CD platform that provides continuous delivery and scalable multi-cloud deployments for Kubernetes projects.

Spinnaker manages CI/CD pipelines and provides robust deployment strategies that make it easy to deploy a new service in Kubernetes. In Spinnaker, version rollbacks and scaling are done directly through the console, which reads the entire cluster and shows all the currently available applications by monitoring its health.

Spinnaker also allows the creation of deployment pipelines that can be triggered and seamlessly integrated with email and Slack for pipeline notifications. These pipelines are utilized for different types of Kubernetes resources and are not limited to deployment.

Spinnaker provides support for various CI tools to perform tests and deploy images to Kubernetes. It’s a fully automated pipeline that supports Helm charts for easy installation.

GitLab

GitLab simplifies the Kubernetes app development by allowing developers to build, test and deploy through a single application.

GitLab contains various CI/CD features like automated code scanning and performance testing to control deployment resources. It also supports Auto DevOps to create a CI/CD pipeline that can be easily set up and managed by DevOps teams for auto-deployment.

GitLab can easily handle thousands of users on a single server while providing the ability to add or remove Kubernetes clusters through CI.

GitLab also tightly integrates with the CI environment by utilizing Deploy boards, which offers a consolidated view of each CI pipeline’s health and state in deployment. Developers can easily monitor the performance, progress, and status of updates by viewing pod logs and enabling Kubernetes integrations.

GitLab is available in both paid and open-source versions. Both offer seamless integration with Kubernetes, while the Paid version also offers enterprise-class features.

Codefresh

Codefresh is an automation platform that streamlines Kubernetes app development by allowing developers to use an extensive set of plugins that can easily integrate with their CI/CD pipelines.

Codefresh makes use of a GUI environment in which various third party CI and image repository tools integrate to create robust CI/CD pipelines.

Codefresh supports Helm charts for easy installation and has its downsides; the CI/CD plugins installed from the GUI can become complex to set up at times. The tool is only available as a commercial tool, which makes it unsuitable for free use.

Travis CI

With 8k stars & 756 forks, Travis CI is not the most obvious choice for a continuous integration platform. Still, it provides plenty of features to sign up, link your repository, build, and test your applications, to run CI/CD pipelines easily.

Travis provides CI-as-a-service, which means it can be easily hosted on a cloud server and does not require any dedicated server to host services. Developers can easily integrate Travis with cloud repositories like Bitbucket and GitHub for quickly creating custom CI workflows.

Travis is available in both free and enterprise versions. The free version can be easily used for open-source projects, while the enterprise version is available for handling commercial projects.

CI/CD Best Practices

Now that we had a look at different CI/CD tools that exist for Kubernetes, we should discuss some best practices to operate them efficiently.

Implement Package Managers and Image Registries

As a part of CI/CD pipelines, it’s essential to check whether all the required tests for your code works correctly. These tests validate the built container image structure while assuring that all commands work as expected inside of your container.

To test and manage these container images, a package manager and image registry are equally important as they offer highly configurable deployment and reliable image management on demand. Helm as a package manager allows easy configuration of multiple environments and easy rollbacking to a previous release with a single command.

Image registries like RedHat Registry, on the other hand, offers secure image retrieval as quickly as possible, which makes it easier to track releases and deployment on multiple cloud providers.

Use Git-based Workflows

Git-based workflows offer better visibility into CI/CD operations by providing significant benefits in terms of ease of use and collaboration. Triggering CI/CD pipelines through Git operations ensures that all changes to applications and clusters are available for review before deployment.

Snapshots of clusters and applications are accessible anytime in cases of failures. Also, Git offers a single source of truth, allowing code changes and tracking, which enables teams to simplify integration through chat tools such as Slack for automating CI/CD tasks while eliminating repetitiveness.

Use Build Only Once Policy

A build once policy implemented at the start of the CI/CD pipeline reduces the chances for errors/inconsistencies introduced later using multiple build tools.

It’s best to build once as rebuilding the image can produce differences across code branches, which can cause applications to fail in production.

Another best practice to decrease application failure is to promote small incremental changes among developer teams as they are easier to integrate and rollback.

Implement a Managed Kubernetes Platform

Choosing the right Kubernetes solution is one of the critical factors that should be considered when achieving agility and speed with the practicality of CI/CD methodologies.

A Managed Kubernetes platform like Digital Ocean and Openshift provide automated integration of workflows and solutions to build a CI/CD pipeline that enables developers to build applications consistently at scale, to meet business needs.

Also, Managed Kubernetes Solutions gets implemented as a SaaS, which reduces operations’ overhead to manage the CI/CD pipeline once it gets deployed into infrastructure. The interface provides simplified management, which allows development teams to focus more on innovation and security.

Conclusion

As a final word, we could say that Continuous Integration and Continuous Delivery tools have become quite popular, and they are made compatible with Kubernetes for seamless integration.

CI/CD and Kubernetes together are highly recommended for organizations looking forward to automating testing and releasing of software. Kubernetes simplifies the automation and helps to get better visibility into the progress of your software delivery lifecycle, while CI/CD pipelines help raise alerts for recovery/failures in software releases during deployment phases.