What is Jenkins? A strategic guide to the automation engine that has been driving DevOps around the world for decades

At the heart of every modern organization that develops software pulses an engine that is invisible to the business, but absolutely crucial. It’s the engine that relentlessly and automatically transforms raw code, created by engineers, into a finished, tested and working digital product, delivered into the hands of customers. This process, called CI/CD (Continuous Integration/Continuous Deployment), is the foundation of the entire DevOps philosophy and the key to achieving speed and quality in today’s competitive market. And if there is one technology that has been synonymous with and the most powerful tool for building this engine for the past fifteen years, it is undoubtedly Jenkins.

For many technology and business leaders, Jenkins is like the legendary powerful machine in the factory – they know it’s crucial, they hear its steady rhythm, but they don’t fully understand how it works, what its strengths are, and what its hidden maintenance costs are. In 2025, in an era dominated by modern, cloud-based platforms, the question of Jenkins’ role and future becomes even more pressing.

In this comprehensive guide, prepared by DevOps strategists and engineers from ARDURA Consulting, we will translate this technical phenomenon into the language of business benefits and risks. We’ll show why Jenkins has defined an entire era in IT, what fundamental problems it solves, but also what strategic choices it confronts leaders today who want to build modern, efficient and future-proof software delivery processes.

What is Jenkins and why has it become synonymous with automation in the software world?

At its core, Jenkins is an open-source (open source) automation server. It’s an extremely flexible and extensible platform whose sole purpose is to perform precisely defined steps and processes in an automated manner. You can imagine it as a tireless digital foreman on the production line of your software factory. Its job is to constantly watch for signals (for example, information that a developer has just written a new version of code) and immediately run a whole, predefined sequence of actions in response.

In the context of software development, this sequence of actions is most often the CI/CD (Continuous Integration/Continuous Deployment) process. Jenkins automatically downloads new code, compiles it, runs thousands of automated tests, analyzes it for security, and if all these steps are successful, deploys the new version of the application to the servers. It is this ability to orchestrate the entire, complex process of building, testing and deploying software that has made Jenkins the de facto global standard and foundation on which the entire DevOps culture has grown.

What is the power and, at the same time, the greatest curse of plug-in (plugins) based architecture?

To understand both the spectacular success of Jenkins and its challenges today, one must understand its fundamental architectural philosophy. Jenkins in its basic version is like a simple but extremely robust engine. Its true, almost unlimited power, comes from a gigantic ecosystem of more than one thousand five hundred plug-ins (plug-ins), created by a global community.

Using an analogy, it can be compared to a kit car. You get a powerful engine and a solid chassis. But you decide the rest. Want to integrate with Amazon Web Services? You install an AWS plugin. Want to analyze code quality with SonarQube? You install the SonarQube plugin. Want to send notifications to Slack? You install the right plugin. This infinite flexibility and extensibility is historically Jenkins’ greatest strength. It allows you to automate virtually any process, even the most niche and non-standard.

However, this same power is also its greatest curse. Managing hundreds of plug-ins from different authors, making sure they are compatible with each other, keeping them up-to-date and resolving the conflicts that inevitably arise is a phenomenon known as “plugin hell.” In large, mature installations, keeping this complex puzzle in good shape becomes an extremely time-consuming and risky task, which is one of the main hidden costs of this platform.

What is “Pipeline as Code” and why has it revolutionized the way we work with Jenkins?

In the early days, configuring tasks in Jenkins was done solely through the GUI, by the method of “clicking” through hundreds of options and forms. Such a way, although seemingly simple, was in fact fragile, opaque and impossible to version. Losing the Jenkins server meant irretrievably losing all the hard-clicked logic.

The real revolution in the world of Jenkins and CI/CD as a whole came with the concept of “Pipeline as Code.” In this modern approach, the entire definition of the build, test and deployment process is stored as code, in a special text file called Jenkinsfile. This file is stored in the version control system (Git) along with the source code of the application itself.

For technology and business leaders, this shift is of fundamental, strategic importance:

• Full auditability and version control: The deployment process itself becomes versioned. At any time, you can see who, when and why you changed the way the application is built or deployed.
• Repeatability and scalability: once defined, a Jenkinsfile can be easily reused in other projects. Templates and shared libraries can be created to ensure consistent processes across the organization.
• Fault tolerance: The configuration of the pipelines is securely stored along with the code. In the event of a Jenkins server crash, it is a matter of minutes, not weeks, to restore and restore all processes.

What does a typical modern CI/CD pipeline (pipeline) orchestrated by Jenkins look like?

The modern CI/CD pipeline in Jenkins is a fully automated, multi-stage production line. While the details may vary, a typical flow looks like this:

1. Signal (Trigger): The process starts automatically when a developer uploads a new code change to a central repository (such as on GitHub).
2. Stage 1: Build: Jenkins downloads the latest version of the code and compiles it, creating a ready-to-install artifact (such as a JAR file for a Java application or a Docker container image).
3. Stage 2: Testing (Test): Jenkins runs a whole set of automated tests – from fast unit tests, to API tests, to slower End-to-End tests. If any test fails, the pipeline is immediately interrupted and the team is notified.
4. Stage 3: Analysis and Security (Scan): The pipeline runs static code analysis tools that check the quality of the code and look for potential security vulnerabilities.
5. Step 4: Deploy to Test Environment (Deploy to Staging): If all the previous steps are successful, Jenkins automatically deploys the new version of the application to the test or development environment.
6. Stage 5: Optional Acceptance (Manual Approval): At this point, the pipeline can stop, awaiting manual approval from a product manager or QA engineer, who can perform final manual tests.
7. Stage 6: Deploy to Production: After getting the green light, Jenkins deploys the new version to production servers, making it available to end users.

Jenkins vs modern SaaS platforms (GitHub Actions, GitLab CI): What is the key strategic difference?

In 2025, Jenkins, despite its still enormous popularity, is no longer the only player in the market. It must compete with a new generation of powerful, fully integrated CI/CD platforms offered in a SaaS model, such as GitHub Actions or GitLab CI. Choosing between these approaches is a key strategic decision.

Jenkins represents a “build it yourself” philosophy. To use an analogy, it’s like building your own fully customized production line in a factory from scratch, using parts from hundreds of different suppliers. This gives you infinite flexibility and complete control, but at the same time places full responsibility on you to maintain, service and ensure the compatibility of all those parts. This is a huge hidden operating cost.

SaaS platforms, such as GitHub Actions, represent a “rent a factory” philosophy. You benefit from a state-of-the-art, fully integrated and professionally serviced production line, delivered as a service. It relieves you of the entire burden of maintenance, offering simplicity and speed of deployment. The price for this convenience is less flexibility and a degree of dependence on a single supplier.

In which business and technical scenarios does Jenkins still remain indispensable?

Despite the growing power of SaaS platforms, there are still scenarios where the unparalleled flexibility and control that Jenkins offers make it the best, and sometimes only, possible choice.

Its power is revealed in complex, heterogeneous enterprise environments, where the CI/CD pipeline must integrate with dozens of different, often outdated systems, running both in the cloud and on-premise servers. Jenkins’ gigantic plugin library is often the only way to bridge these distant worlds.

It is also indispensable in organizations with the highest requirements for data security and sovereignty, such as the government, defense and financial sectors. The ability to run a fully functional automation server on its own fully Internet-isolated (air-gapped) infrastructure is often a key regulatory requirement.

Finally, Jenkins remains the best choice for highly customized, unique automation processes that go far beyond typical CI/CD and that cannot be modeled in more structured and “opinionated” SaaS platforms.

What are the biggest costs and risks of maintaining your own Jenkins instance?

The decision to base your automation strategy on self-managed Jenkins must be made with an awareness of the real long-term costs and risks, which are often underestimated.

The biggest hidden cost is the constant need for maintenance and updates. Both the Jenkins core itself and the hundreds of plugins require regular updates to patch security vulnerabilities and introduce new features. This is a never-ending, time-consuming process that requires the attention of your DevOps team.

With that comes the risk of fragility and instability. Updating one plugin can cause a conflict with another, which can lead to the failure of the entire deployment pipeline. Diagnosing and resolving such issues in a complex “plugin hell” can take days.

Finally, keep in mind the security risks. As a critical piece of infrastructure that is often accessible from the Internet, the Jenkins server is a greedy morsel for attackers. Full responsibility for hardening, monitoring and securing it rests with your organization.

What does it mean to “modernize” Jenkins and how can new life be breathed into it in the cloud era?

Many companies with huge historical investments in Jenkins face a dilemma: whether to undertake a costly and risky project to migrate to a new platform, or try to modernize the existing solution. Fortunately, modern practices allow for a significant “refresh” of Jenkins.

The first and most important step is to fully adapt the “Pipeline as Code” philosophy and migrate all old, clickable tasks to fully versioned Jenkinsfiles.

The second revolutionary step is to run Jenkins on Kubernetes. Instead of installing it on a single, fail-sensitive server, it can be run as a scalable and fault-tolerant application in a Kubernetes cluster. This also allows the use of so-called “ephemeral build agents,” which significantly improves performance and security.

The third step is to rationalize and ruthlessly “slim down” the list of plug-ins. Regular auditing and removal of all unused or unnecessary plug-ins significantly reduces the complexity and attack surface.

How do we at ARDURA Consulting approach automation strategies and CI/CD evolution?

At ARDURA Consulting, we understand that the heart of DevOps is the process and culture, and that tools are just a means to an end. That’s why our CI/CD collaboration with clients is always strategic and technology agnostic.

We start our process with a Holistic DevOps Maturity Assessment, during which we analyze the entire software delivery value stream in the organization to identify the real bottlenecks. Sometimes the problem is outdated Jenkins, and sometimes it’s the processes and culture around it.

Based on this analysis, we make a pragmatic, data-driven recommendation. We calculate TCO and ROI for two paths: upgrading your existing Jenkins or migrating to a modern SaaS platform. Whichever path you choose, our DevOps experts have the deep knowledge and experience to carry out the process safely and efficiently. Our goal is always to build a robust, secure and easy-to-maintain automation platform that realistically accelerates customer innovation.

Investment in speed and confidence

A CI/CD automation platform, whether it’s the battle-tested Jenkins or a modern SaaS solution, is the absolute heart of the innovation engine in any modern technology company. Its performance, reliability and speed directly dictate the speed at which your organization is able to transform business ideas into value delivered to customers.

Having a slow, unreliable and manual implementation process in 2025 is a gigantic and unacceptable competitive advantage. In contrast, investing in a fast, fully automated and secure pipeline is the most powerful strategic weapon you can have. It’s an investment in speed, quality and, most importantly, in trust – both from your customers and your own development teams.