Best of 2021 – 7 Popular Open Source CI/CD Tools

As we head into 2021, we at wanted to highlight the most popular articles of the year. Here is the fourth episode in our Best of 2021 series.

DevOps is a software development strategy that includes agile practices for rapid and efficient product creation and release. It focuses on the integration of development teams and operations, continuous integration/continuous delivery (CI/CD) and the automation of tasks and processes.

DevOps teams typically use pipelines to simplify and standardize processes. DevOps pipelines are tool chains that teams can use to automate tasks and provide visibility into the software development lifecycle. In this article, we will cover seven popular open source CI/CD tools.

How will DevOps change in the near future

Although DevOps has been around for just over a decade, it has continued to evolve. New DevOps technologies and changing infrastructure have caused teams to adapt to technological advances that will continue to make a difference. Here are some of the ways you can expect DevOps to evolve in 2021 and beyond.

Artificial intelligence and data science

Artificial intelligence (AI) and machine learning have great potential to improve existing DevOps operations. Teams can use AI to identify pipeline inefficiencies, improve testing, or assess user needs. Increasing amounts of data about individual environments, customers, markets, and habits can be applied to increase productivity and, ultimately, revenue.

Serverless architectures

Serverless platforms such as the AWS serverless ecosystem, including AWS Lambda and Fargate, and the serverless Azure platform, including Azure functionality and Azure App Service, are becoming increasingly popular. These platforms enable DevOps teams to focus solely on their code and eliminate many other variables, such as caring about host operating systems. These architectures provide scalability, deployment speeds, and user experiences that are hard to match. This value will further secure the FaaS in the coming years.

original cloud

The growth of cloud-native applications has been driven and fueled by the widespread adoption of cloud services. The containers and microservices that make up many cloud applications are used in many pipeline deployments and environments. Efficiently developing cloud-native applications requires speed and automation that is difficult to meet without DevOps strategies.

For the above reasons, DevOps has become almost synonymous with cloud-native. As cloud-native technologies change, so do tools and processes. Additionally, as cloud growth does not slow down, you can expect DevOps to continue to focus on cloud-native development and improvement.


When developing applications in an automated CI/CD pipeline, security cannot be an afterthought. Especially in complex microservice architectures, security must be built in from the planning and development stages. Everyone should be aware of the security requirements – developers, DevOps engineers, infrastructure teams.

Moving to the DevSecOps model requires a culture change, but it also requires a new set of technologies. Changing security to the left requires tight integration of application security tools into the development lifecycle, implementation of cloud security solutions that can help gain visibility, and implementation of automated security controls, on complex cloud environments.

What CI/CD Tools Will You Use in 2021 and Beyond?

As technologies change, so do the tools. While you can continue to use the same tools you started with, you should at least consider whether other tools can increase your efficiency. Here are some of the popular open source tools that you may want to incorporate.

Argo CD

Argo CD is a CI/CD tool for Kubernetes development. It is an open source project and is currently in incubation status at the Cloud Native Computing Foundation (CNCF). It uses Git repositories to store the state of Kubernetes applications, monitor applications and can re-sync groups to the desired state, as shown in the git configuration.

This innovative approach also allows you to store multiple desired states of a Kubernetes application, using branches, tags, or by installing manifest versions using the Git commit. This provides a flexible environment for managing Kubernetes configurations during the development process.


CircleCI is an open source CI/CD tool. It includes features for organizing jobs, configuring resources, caching, debugging, security, and dashboard reporting. CircleCI integrates with a variety of tools, including GitHub, Heroku, Slack, and Docker.

CircleCI is available in three tiers, one of which is free. You can use it in the cloud or on-premises with Linux, Mac, or Windows devices.

GitHub Actions

GitHub Actions is a recently released open source tools feature that you can use to automate workflows. It enables you to generate, test and publish code directly from GitHub. You can build your automation on any GitHub events, including push or release builds.

GitHub routines include features for matrix workflows, hosted runners for all major operating systems, embedded secret storage, and live history reviews. It supports all popular programming languages.

GitHub Actions include hosted runtime environments that can be used free of charge for the first 2,000 minutes of use per month. If you need more time for testing, you can buy time by the minute or in bulk. You can use GitHub actions by including them in your YAML files.


GoCD is an open source build tool that allows you to build CI/CD development pipelines. In essence, it is a Continuous Integration (CI) server, which allows you to work with complex release workflows. It goes beyond classic CI to let you build a continuous delivery (CD) pipeline, all the way from automated and secure deployment to production.

GoCD identifies pipelines using validated code in source control – the Infrastructure as Code (IaC) approach allows you to test, manage, and reuse pipelines across multiple projects. Pipelines can be represented by JSON or YAML templates.

Another advantage of GoCD is the ability to run pipelines sequentially and in parallel, with configurable dependencies. View entire workflows from development to production and track a feature from initial commitment to production deployment, using value flow planning.

GoCD is very flexible, and provides an ecosystem of plugins and tool that also allow you to develop and contribute your own.


Gradle is an open source build automation tool that has been around for about a decade. It is still well approved and supported. Although it is not a new tool, it can be a good alternative if you are looking to replace Maven as a build management solution. Gradle is more extensible and faster than Maven, and can be used for local development of C/C++ applications.

Gradle includes features for additional builds, build caching, and parallel execution. It supports a variety of languages ​​and platforms, including Java, Scala, Android, and C/C++. You can integrate Gradle with a range of tools, including Eclipse, IntelliJ, and Jenkins.

You can use Gradle on-premises or with a virtual machine in the cloud. Gradle is free to use; However, if you want to support the institution or training, you need to pay an additional fee.


Helm is an open source Kubernetes package manager. You can use it to select, install, and upgrade your Kubernetes formatted applications. Helm includes a large set of pre-made schemas (collections of Kubernetes Distributable Resources) that you can use to deploy services faster and more easily. You can use Helm on Linux, Mac, and Windows machines.

Jenkins X

Jenkins X is an updated version of the well-known Jenkins. It builds on existing Jenkins features with capabilities designed specifically for Kubernetes and Docker workflows. It includes features for pre-built pipelines, integrated GitOps support, auto-generated preview environments, and feedback integration.

Jenkins X integrates with Tekton, Prow, Helm, Knative, and Skaffold. You can use it on Linux, Mac or Windows devices.

CI/CD and automation go hand in hand

Agile teams need automation tools, especially when creating and working with CI/CD pipelines. DevOps environments are dynamic, and they are designed for smooth work flow and constant change. Automation helps DevOps teams maintain a high level of visibility and reduce time spent on repetitive tasks. When AI and data science are added to the mix, DevOps teams gain the ability to make data-driven decisions, as well as automated alerts and response.

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