Build times are the bane of a DevOps engineer’s existence. A slow build not only impacts your immediate work but slows down your entire team and the product delivery cycle. Hours, and sometimes even days, can be lost as builds drag on, with developers waiting to test their code and features held up. So, you’re not alone if you’re looking for ways to speed things up. This article will show you how to make your Jenkins builds faster.
Why Your Jenkins Builds Might Be Slow
Before we dive into fixes, let’s understand why your Jenkins builds may be sluggish. Many factors can contribute, but here are the usual suspects:
- Resource limitations: Your Jenkins server may not have enough RAM, CPU, or disk space. If these are maxed out, builds will crawl.
- Inefficient pipeline configuration: A poorly designed pipeline, with too many steps or poorly optimized tasks, can be a major drag.
- Plugin overload: Too many Jenkins plugins can slow down your server. Especially if they are not kept up to date.
- Large artifact handling: Huge build artifacts, especially if not managed well, can hog resources and slow things down.
- Network bottlenecks: A slow or unstable network between your Jenkins server and other systems it interacts with can also slow build processes.
- Inefficient code: Code that takes a long time to compile or run will extend build durations.
- Lack of parallelism: Builds that run sequentially when they can run in parallel waste a lot of potential time savings.
- Outdated software: Outdated Jenkins, plugins, or build tools can contain bugs or inefficiencies that slow builds down.
- Incorrect caching: If your caching isn’t set up well, Jenkins will waste time rebuilding or fetching resources that could have been stored locally.
Identifying the specific choke points in your builds will be the first step to speeding them up.
Resource Optimization for Faster Builds
One of the most straightforward ways to speed up Jenkins is to make sure it has the resources it needs. Here are some key areas to address:
Beef Up Your Server
If your builds often lead to resource spikes, consider upgrading your Jenkins server. This might mean adding more RAM, CPU cores, or faster storage. Start by monitoring your system. Tools like top or htop on Linux servers can show you resource use in real time. If you see sustained CPU or RAM usage above 80%, it’s time to upgrade.
If you use a cloud server, most providers offer an easy way to change the server size with a few clicks. If you’re on a physical server, you may need a bit more time to plan the upgrade. Either way, the end result should be well worth the effort.
Optimize Storage
Disk I/O can be a huge bottleneck, especially with large builds. Moving your build workspace and Jenkins installation to SSD storage can make a big difference. SSDs have faster read and write speeds than traditional hard drives, leading to quicker load times and build processes. If you use a cloud provider, you can change the storage configuration of your virtual machine or use premium SSD options with no problem at all.
Also, keep an eye on the disk space used by old builds and logs. Clean them up on a regular basis to free up space and improve I/O speed. You can do this manually or use Jenkins plugins to help you do it.
Manage Concurrent Builds
Jenkins can run multiple builds at the same time. If you overload your server, performance suffers. Set a limit to the number of builds that run at once to match your server’s resources. Too many builds will lead to builds waiting in queues. This adds up to build times and wasted dev cycles.
To do this, go to “Manage Jenkins” then “Configure System”. Look for the “# of executors” setting, and make sure this is equal to the number of logical cores on your server. If you have multiple Jenkins agents, you can also set the number of executors per agent as well. This keeps things smooth and prevents builds from clashing.
Use Jenkins Agents
Jenkins agents allow you to offload builds from your main Jenkins server. This can drastically improve overall build speed. The agents do the build process while Jenkins manages the pipelines. Distributing builds across agents can handle parallel builds, and a main Jenkins server.
You can set up agents on other servers, virtual machines, or even containers, depending on your needs. Jenkins provides several plugins for different types of agents such as SSH, or JNLP.
Pipeline Optimization Techniques
A badly set up Jenkins pipeline can be just as much of a hurdle as underpowered hardware. These tips will help you make your pipeline more efficient:
Split Large Pipelines
One massive pipeline with everything in it is hard to manage and hard to debug. Break your pipeline into smaller parts. This makes each stage easier to understand and more efficient to run.
For instance, split build, test, and deployment steps into their own jobs. You can then trigger these jobs in sequence or in parallel depending on your use case. Not only is it easier to manage, but it means stages can run as needed, and not as one gigantic whole.
Parallelize Stages
If you have stages that don’t depend on each other, run them at the same time. Jenkins has features that can easily split tasks. This way, your build runs much faster since all the stages don’t need to happen one by one.
Use parallel steps for tasks like static code analysis, unit tests, or building for multiple environments. By doing this, you can see great gains, especially in large codebases. This will change total wait times from a sum into just the time it takes to complete the longest stage.
Optimize Build Steps
Every command in your pipeline matters. Look for ways to make your build steps more efficient. For instance, some tools use lots of CPU and take up more time. You may be able to use faster alternatives to complete the same tasks.
For example, check if you’re using optimized compilers or build tools. Also, look into how you manage dependencies. Using caching mechanisms in your build tools to download dependencies only when they change will be a great time saver.
Use Declarative Pipelines
Declarative pipelines in Jenkins are easier to read and write than scripted ones. They are less error-prone and easier to maintain. Declarative pipelines also support parallel execution and other performance optimizations more easily. If you are still using scripted pipelines, look into transitioning.
Declarative syntax will also make it easier for people who aren’t overly familiar with Jenkins to understand. This will be a great help in cross team collaboration.
Cache Dependencies
Fetching dependencies every build is a huge time waste. Jenkins caching features or build tool caches to store these dependencies can make builds much faster. Tools like Maven and Gradle have caching features. Use these as your build tools, and let your build steps take advantage of them.
Use Jenkins workspace caching or a dedicated artifact repository like Nexus or Artifactory. This way, dependencies are fetched from local storage most of the time. Only when the dependencies change is when Jenkins needs to go out to fetch them again.
Plugin and Software Management
Jenkins plugins can add powerful functionality, but poor plugin management will create more problems. Here is how to deal with plugins and software versions in your Jenkins setup:
Keep Plugins Up to Date
Outdated plugins can have bugs that slow down builds or conflict with other plugins. Keep your Jenkins plugins up to date. This is the best way to make sure you are using their most efficient version.
Jenkins provides an easy way to see and update plugins in the “Manage Plugins” page. Also, consider disabling or uninstalling plugins that you no longer use.
Use Specific Plugin Versions
Use specific versions of your plugins. This gives you more control over your builds. You avoid surprise updates that can break your pipeline. This way, any changes in a plugin will be tested and vetted. When you are ready to update the plugin, you can then do so.
You can do this by specifying the plugin version in your Jenkinsfile or pipeline configuration. Jenkins also allows you to install plugins using the plugins.txt file, this allows the plugin version to be version controlled.
Maintain a Minimal Plugin Set
While plugins add great features to Jenkins, each plugin adds overhead and takes up server resources. Only install the plugins you really need. Try to use built-in Jenkins features as much as you can. This will keep your setup lean.
Review your plugins regularly and disable or remove the ones that are not used. Use your plugins.txt file to keep track of them.
Keep Jenkins Up to Date
Just like plugins, old Jenkins versions can cause issues. Upgrade Jenkins often to benefit from the latest bug fixes, speed improvements, and security patches. Do this in a planned way, where you’re ready to address issues should they arise.
Jenkins publishes regular updates. Before upgrading, back up your configuration and test the new version in a staging environment.
Artifact Handling Strategies
Build artifacts can be big. Handling them properly will keep your builds quick and reduce pressure on Jenkins resources. Here is how to manage your build artifacts:
Use Artifact Repositories
Instead of storing build artifacts on Jenkins, use a dedicated artifact repository like Nexus or Artifactory. These tools are designed to store and manage build artifacts. They also offer caching features.
These repositories handle storage, versioning, and security of your artifacts in a far better way than Jenkins. Jenkins integration with these systems is also very well-established, making this a no-brainer.
Optimize Artifact Storage
When storing artifacts, compress them to save space. Delete old versions of artifacts that you no longer need. Do this in a planned and organized way, and never do this manually.
Use the features of your artifact repository to create artifact lifecycle rules that delete old versions. This helps keep your storage costs down, and build times lower.
Use Incremental Builds
When possible, use incremental builds. This makes it so that only parts of your code that change are rebuilt. This saves a lot of time by avoiding full builds every time.
For example, if only one part of your code is changed, only that part of the code will be rebuilt. If you use a good build tool, you are already taking advantage of this strategy.
Compress Artifacts
Artifacts are usually compressed to save storage space. Artifact compression also reduces network traffic. This can lead to faster download speeds. These things greatly speed up build time.
Use compression algorithms like GZIP or ZIP to compress your build artifacts before storing them. This not only speeds up downloads, it also helps save storage space.
Network and Infrastructure Tweaks
A good network is a must-have for fast builds. Here’s how you can ensure your network is optimized:
Monitor Network Performance
A slow network will slow down your Jenkins builds. Monitor your network to find any possible problems. Use network performance tools to identify any slowdowns. This helps you take action before it impacts build times.
Use network monitoring tools like iperf or cloud-based monitoring tools to get real time insight into network performance. Also, keep an eye on network latency between Jenkins and other systems it connects to.
Locate Jenkins Near Resources
Keep your Jenkins server close to the systems it needs to reach. This means having it closer to your source code repository, databases, and artifact storage. This minimizes network latency and reduces the time it takes to fetch or push data.
In cloud environments, place your Jenkins server in the same region and zone as your other resources. This provides a very fast local network for your builds.
Use a CDN
If you use resources on the internet that your builds depend on, using a CDN (Content Delivery Network) can help. CDNs store content on servers all over the world. Your builds will get resources from the server that is closest to it. This makes download speeds much faster.
CDNs are particularly helpful if your builds download large libraries or other resources from internet sources. This reduces network traffic and speeds up downloads.
Load Balance Jenkins
If you have lots of builds, use a load balancer to spread the load across multiple Jenkins servers. This prevents a single server from being overloaded. This will keep builds running smoothly even during peak periods.
This setup can help you scale Jenkins horizontally. Add more Jenkins instances to handle the demand. The load balancer will ensure that builds are distributed evenly.
Code and Build Process Optimizations
The code you build and the way you build it matters. Here are a few things you can do to make sure your builds are fast:
Optimize Code
Slow code means slow builds. Optimize your code to improve build times. This includes things like improving algorithms, removing unneeded code, and using faster tools.
Regular code reviews, and static analysis tools will help you find areas in your code that need improvements. The faster your code compiles and runs, the faster your builds will be.
Clean Up Workspace
Make sure to clean up the Jenkins workspace after every build. This removes unnecessary files. This also prevents the workspace from getting too big, which slows down builds.
Jenkins has built in options to do this automatically. It also has plugins that will help do this on the fly. Either way, you should clean your workspace regularly.
Use Proper Build Tools
Use build tools that are fast and efficient. Tools like Gradle or Maven are good for Java. Tools like Make or CMake are good for C++. Choose the right build tool for your use case. This is key to fast builds.
Use the advanced configuration features of your build tools. These options help improve build times. Also keep your build tools updated to their latest versions for any performance improvements.
Reduce Code Changes
The smaller the code changes are, the faster your builds will be. Small changes are easier to compile and test, and they reduce the risk of introducing errors. Smaller changes can also be tested more often, reducing the cost of changes.
Encourage a coding style that uses small and targeted changes. Use code review tools to make sure that changes are small and relevant. Also, build systems can use the code changes to compile only the code that has changed, making builds much faster.
Fail Fast
Set your builds to fail fast. This means stopping the build process as soon as a failure is found. Don’t continue the build if a critical test fails. This helps you find issues earlier in the process. It will also keep the build shorter.
This strategy can be easily implemented in a declarative pipeline where any failed stage will halt the entire pipeline.
Monitoring and Continuous Improvement
Optimizing your Jenkins builds is not a one-time job. Continuous monitoring and improvement are needed to keep your builds fast. Here’s how to go about it:
Track Build Times
Track how long your builds take over time. This will help you identify when build times increase. Keep an eye on which builds are slow, and why.
Jenkins has a built-in feature to record build times. You can use this to create reports and graphs that can help you monitor performance.
Implement Automated Monitoring
Use automated tools to monitor the health of your Jenkins server and pipeline performance. Set up alerts for slow builds, server issues, or other problems. Make it so that you know when problems happen.
Tools like Prometheus and Grafana can be used to monitor Jenkins and generate alerts. This lets you address issues as they happen, and not when your developers start complaining.
Regularly Audit Your Setup
Review your Jenkins setup often. Find areas to improve build speed. Look at your plugins, pipeline configs, and resource usage. Keep your setup lean and efficient.
Automated scanning tools are a great way to audit your Jenkins setup for issues. Regular reviews are also a good way to make sure you apply all the best practices for speed.
Continuously Refine
Use the information you gather to improve the build process continuously. As your code base and team evolve, build processes should evolve with it. Find bottlenecks, use the methods outlined here, and apply them. This will keep your builds running smoothly over time.
Look at the feedback you get from monitoring tools and team members, and address those issues first.
Applying the Fixes
Now that you have a good understanding of how to speed up Jenkins, it’s time to apply these fixes to your builds.
- Start with resource upgrades: Upgrade your server’s hardware or use Jenkins agents.
- Optimize your pipelines: Break large pipelines, parallelize stages, and cache dependencies.
- Manage plugins and software: Keep plugins and Jenkins up to date and use only the ones you need.
- Handle artifacts properly: Use artifact repositories, compress artifacts, and use incremental builds.
- Refine your code: Optimize code, clean up your workspace, and use good build tools.
- Monitor your results: Track your build times and always make sure they are optimal.
Start with a few simple changes that you can easily implement. Then slowly add on more fixes. Remember to make changes incrementally. Test those changes before you make more. This way you can track your progress, and reduce possible issues.
Wrapping Up: Faster Builds, Happier Teams
Speeding up Jenkins builds requires a good mix of hardware upgrades, pipeline optimization, and good management practices. You can greatly improve your build times by finding what is slowing your build, and applying the methods in this article.
Remember that fast builds not only save time, they boost team happiness and improve the development workflow. By making your Jenkins builds fast, you will improve the development process, and reduce frustration. A faster development process means faster time to market, and more features delivered to your end users.