Jenkins Performance: Improve CI/CD Pipeline Speed & Response

Jenkins is an open-source automation server written in Java, that helps in automating software development. It streamlines the process of building, testing, and deploying code. Well, Jenkins is used to implement continuous integration/continuous deployment (CI/CD) workflows known as pipelines.

The pipeline provides various tools for modelling delivery pipelines as code. You can version control and treat the pipeline configuration like any other code. Pipelines automate testing, help build software, automate build tests, and help deploy code to virtual machines, servers, or, containers. Since these pipelines play a key role in the software development process, it’s essential to optimize them for fast performance. Ideally, you need fast, highly responsive pipelines to accelerate your build, test, and deployment processes.

This article explains some of the best practices to improve Jenkins CI/CD pipeline speed and responsiveness. Read on!

Jenkins Performance: Improve CI/CD Pipeline Speed & Response

1. Clean Up Old Builds

One of the top methods of improving Jenkins performance is clearing your build history. Having too many old builds consumes a significant amount of disk space, which slows down Jenkins. These old builds have significant amounts of data, like artifacts, test results, and console output which add over time to consume system resources. Jenkins fingerprints also pile up, causing your instances to run out of nodes.

When you clear Jenkins build history, you optimize disk usage, hence enhancing the CI/CD pipeline performance. To maintain an efficient CI/CD pipeline, it’s crucial to only maintain relevant data. You should systematically delete any other unnecessary information. Because some builds are more important than others, utilize Jenkins policies to keep these builds. By automating with policies, you minimize chances of human error and make the system more efficient and increase pipeline reliability.

2. Run Jenkins Tests in Parallel

Parallel testing in Jenkins enables you to run multiple tests on different environments or machines simultaneously. Running Jenkins tests in parallel offers multiple benefits and significantly reduces the time it takes for a Jenkins pipeline to execute. It allows you to create pipelines with parallel stages to run tests concurrently. Comes in handy when building resource-heavy workloads. 

Please ensure tests are independent and don’t collide with each other. Orchestrate these tests to avoid conflicts.

3. Implement Jenkins Pipelines as Code

Jenkins has a web UI that enables users to create jobs manually via browsers. However, this requires additional effort to manage jobs and test and build projects. Also, it separates the job configuration with the actual code, preventing users from applying their existing CI/CD best practices. To avoid this, implement Jenkins pipelines as code.

Pipeline as code refers to a set of features that enable users to use code to define pipelined jobs. The code is stored and versioned in a source repository. This way Jenkins discovers, manages, and runs jobs from multiple repositories and branches. With pipeline as code, you apply the same principles of software development to the pipeline configuration, including version control, code review, and continuous integration.

The pipeline-as-code approach improves collaboration among developers as they jointly develop, test, and maintain the pipeline code. Besides, the code is more accessible and transparent, which makes the pipeline configuration process more consistent and error free. This process speeds up the CI/CD process as teams track every change made, revert to a previous state when necessary, and identify issues quickly

4. Use Appropriate Plugins

Jenkins plugins are all designed to enhance how your CI/CD pipelines. They help integrate with other tools, automate repetitive tasks, simplify configuration, and more. However, you easily get confused by the large number of plugins. Therefore, do not install too many plugins  as it slows down your jobs during builds.

Use necessary plugins that minimize the load on the Jenkins server and reduce the risk of conflicts. This way, you have a stable and efficient Jenkins environment with fast pipeline execution. Also, whenever you no longer need a plugin, uninstall it to free your Jenkins environment. Basically, you should keep your Jenkins instance lean with a minimal set of plugins to significantly enhance the pipeline’s performance.

5. Use Flyweight Executors

Executors in Jenkins are the workhorses that carry out the build jobs. There are two types of executors- heavyweight and flyweight. Heavyweight executors run on Jenkins Slave nodes and are configured on the node’s configuration. On the other hand, the flyweight executor is a Java thread that runs on the Jenkins Master node. These executors are created automatically when needed, and removed when no longer needed.

Use lightweight executors as they consume fewer resources and don’t require a heavy runtime environment. This results in quicker start times for jobs and less strain on the Jenkins master. 

Besides, use Docker or Kubernetes to dynamically spin up lightweight executors on demand to further optimize resource usage. Set the containers to run for the duration of a task and then discard them, ensuring efficient resource utilization and a faster, more scalable and responsive pipeline.

6. Set Appropriate Memory Limits

This approach helps prevent out-of-memory errors and sluggish performance. There are several Jenkins memory allocation best practices you leverage to allocate sufficient memory limits. First, you need to adjust the JVM heap size depending on the size of your projects, the number of jobs, and the system’s available memory.

Avoid having a small heap size as it causes frequent garbage collection, leading to performance reduction. On the other hand, you need to avoid oversized heap sizes as that leads to wasted resources. Besides, it causes JVM to crash if it exceeds the available memory. Therefore, you need to tune the JVM settings according to your specific workloads to optimize performance and stability of your Jenkins CI/CD pipeline. Additionally, set memory limits for Docker containers running Jenkins agents. This ensures that a single build job cannot deplete the available system resources.

7. Optimize Jenkins Scripts

Scripts are an integral part of a Jenkins pipeline. They help automate tasks, integrate tools, and manage the pipeline flow. However, poorly written or inefficient scripts slow down your CI/CD pipeline and impact its performance. To optimize them create them in such a way that reduces their execution time, and minimizes resource consumption. Efficient scripts execute faster, use fewer resources, and reduce the load on the Jenkins server. This results in improved pipeline performance.

Besides, create scripts that you reuse across multiple pipelines or jobs. This reduces the need to write new scripts for each task and promotes consistency across pipelines. Finally, review and update your scripts regularly. This detects and eliminates performance issues and ensures that your pipeline remains as efficient as possible.

8. Avoiding Complex Groovy code in Pipelines

Jenkins comes with a Groovy script console that runs the scripts within the runtime on agents or in the Jenkins controller runtime. Since Groovy code is always executed on the controller, it consumes memory and CPU. Therefore, to optimize the use of controller resources, it is essential to minimize the amount of Groovy code used by Pipelines. This includes any methods called on classes imported into Pipelines. 

One of the  Groovy methods to avoid is the ‘JsonSlurper‘, used to read data from a file, parse it into a JSON object, and then inject it into a Pipeline. This process usually leads to heavy memory usage, especially if the file is large or the command is frequently executed. In order to avoid using the ‘JsonSlurper’ method, use a shell step and return the standard output. This approach allows you to leverage agent resources to read the file, and the parsing query helps to reduce the file into a more manageable size. An example of this would be: def JsonReturn = sh label: ”, returnStdout: true, script: ‘echo “$LOCAL_FILE”| jq “$PARSING_QUERY”‘.

Another Groovy method to avoid is the ‘HttpRequest’, which is commonly used to fetch data from an external source and store it in a variable. This is not an ideal practice, as the request originates directly from the controller and the response is stored twice. To avoid using ‘HttpRequest’, consider using a shell step to perform the HTTP request from the agent. Consider using shell features such as curl or wget. The goal is to filter the result as much as possible on the agent side. This way, there is minimal information transmitted back to the Jenkins controller. Remember, to have efficient Pipelines, you have to reduce the load on your controller. This happens when you minimize the use of Groovy code and maximize the use of agent resources.

9. Configure and Optimize Garbage Collection

Garbage collection (GC) is a feature of the Java Virtual Machine (JVM) that acts as an automatic memory management system. The GC identifies unused objects in the heap and frees their occupied memory. However, some GC actions cause your application to temporarily pause. These pauses are become long if your GC settings aren’t correct, leading to a negative impact on system performance.

To tune the Garbage Collector to enhance Jenkins performance, start by enabling G1GC, the most advanced GC implementation. Follow this with enabling GC logging. These logs help to monitor GC behaviour and guide your future tuning efforts. If your application has a large heap (greater than 4GB), this leads to more frequent application pauses, necessitating GC tuning to shorten these pauses.

As you continue your optimization process, observe GC behaviour and adjust GC settings using additional flags as needed. This is not a one-time fix; optimizing GC is an ongoing process. Continual monitoring and adjustments based on your observations helps to maintain optimal Jenkins performance.

10. Implement Continuous Pipeline Monitoring

Monitoring Jenkins is highly crucial as it provides 360-degree visibility into automation workflows like code transitions, memory leak scans, and static code analysis. By keeping an eye on metrics such as memory and CPU usage, build success rate, and queue lengths, you ensure that these pipelines are operating effectively. If an issue arises, like a malfunctioning pipeline, real-time monitoring allows you to act swiftly, preventing prolonged interruptions to your essential processes.

Jenkins monitoring also helps detect anomalies in real time. Anomalies arise due to various factors, including system errors, plugin issues, or flawed pipeline code. Configure alert mechanisms on your monitoring system, to be notified of potential problems such as high disk usage or server resource depletion.

Thank you for reading Jenkins Performance: Improve CI/CD Pipeline Speed & Response. We shall conclude the article. 

Jenkins Performance: Improve CI/CD Pipeline Speed & Response Conclusion

Jenkins helps DevOps teams to collaborate for a seamless software development environment. By leveraging Jenkins, teams accelerate their CI/CD speed and deliver high-quality software at a faster pace. Configure Jenkins in a way that optimizes pipeline speed and responsiveness. By implementing the above best practices, you improve your overall Jenkins server performance. This leads to faster automation, more fault resistant builds and increased product quality.

Avatar for Dennis Muvaa
Dennis Muvaa

Dennis is an expert content writer and SEO strategist in cloud technologies such as AWS, Azure, and GCP. He's also experienced in cybersecurity, big data, and AI.

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