Large plugin sets, many jobs/users and build histories can expand controller heap demand. Current Jenkins tuning guidance treats heap sizing and GC as a controller-performance problem.
Growing CI controllers.Hardwarevereisten voor Jenkins CI/CD: RAM voor de controller, agents en builds
Leer de vereisten voor RAM, schijfruimte, Java 21, build-agents en CI-workloads van een Jenkins-controller en kies vervolgens geschikte ZimaOS-hardware.
Jenkins CI/CD requirements at a glance
Jenkins publishes both a tiny installation floor and much larger practical sizing guidance. Current Linux installation docs list 256 MB RAM and 1 GB disk as minimums, with 10 GB disk recommended for Docker; a small team is recommended to use 4 GB+ RAM and 50 GB+ disk. The crucial architecture rule is to keep heavy builds off the controller and delegate them to agents.
- Controller RAM minimum
- Official installation floor: 256 MB. Jenkins' scaling guide says real controllers range from about 200 MB to 70+ GB depending on scale.
- Small-team RAM
- Official small-team recommendation: 4 GB+ RAM.
- Disk
- Official minimum 1 GB; 10 GB recommended when Jenkins runs in Docker; small-team recommendation is 50 GB+ because JENKINS_HOME stores plugins, configuration and build history.
- Java
- Current Jenkins LTS/weekly lines require modern Java; Jenkins 2.555.1+ LTS supports Java 21 or Java 25.
- Build agents
- Jenkins explicitly advises against running build executors on the controller. Agent hardware should be sized from the actual compiler, test, Docker, Android, Java, Node, Rust or other build workload.
- Best Zima starting point
- ZimaBoard 2 832 is a strong controller-only host. Use 1664 or ZimaCube 2 Pro when the same physical server also hosts agents, artifact caches or other developer services.
From official requirements to the right setup
Jenkins sizing starts by separating orchestration from compilation and testing.
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Official requirements
Size the controller first: Java, plugins, users, job configuration, JENKINS_HOME and build history. A small controller can be modest, while plugin-heavy/high-user installations need far more heap and storage.
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Confirm your needs
Move builds to agents. Jenkins' own scaling guidance calls controller executors a bad practice because builds can overload the controller and cause downtime.
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Leave room to grow
Size each agent from the toolchain it runs. A small shell/test agent can be light, while Docker image builds, Java compilation, Android builds or browser tests can need many cores, GB of RAM and large caches.
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Run it on ZimaOS
Install Jenkins from ZimaOS, keep JENKINS_HOME on reliable persistent storage, run representative pipelines through agents and monitor controller heap/GC separately from agent CPU/RAM/disk.
Check every playback client
- Controller-only versus local build executors
- Number of jobs and users
- Plugin count and controller heap
- Build history/artifact retention
- Number of connected agents
- Build toolchain CPU/RAM requirements
- Docker image/cache storage
- Java 21/25 compatibility
Official minimum requirements
Jenkins current installation and scaling documentation gives explicit startup, small-team and controller-sizing guidance.
256 MB RAM is a technical installation floor, not a modern CI recommendation. For a small team, 4 GB+ RAM and 50 GB+ disk is the more useful controller reference, while builds should be offloaded to agents.
| Requirement | Official minimum | What this supports |
|---|---|---|
| RAM minimum | 256 MB | Official installation floor. |
| Disk minimum | 1 GB | 10 GB is recommended if Jenkins runs as a Docker container. |
| Small-team RAM | 4 GB+ | Current Jenkins recommended hardware configuration for a small team. |
| Small-team disk | 50 GB+ | Allows more room for JENKINS_HOME, plugins, logs and build history. |
| Controller memory scale | About 200 MB to 70+ GB | Jenkins hardware recommendations emphasize there is no one-size-fits-all controller. |
| Current Java | Java 21 or Java 25 for current LTS 2.555.1+ line | Check the Java support policy when upgrading Jenkins. |
When to upgrade your hardware
Upgrade Jenkins when controller health or agent workload—not the dashboard—requires it.
Controller heap/GC and UI latency become unstable
Builds are still running on the controller
Build agents need more CPU, RAM or cache storage
The first fix is architectural: move builds to agents rather than buying a larger controller. Jenkins explicitly warns that controller executors can overload CPU and memory.
Small self-hosted Jenkins installations that started as all-in-one.Compiler/test workloads scale independently from Jenkins. Docker builds, JVM tests and monorepos can need much stronger hardware than the controller.
Teams with heavier or parallel pipelines.Plan hardware growth with confidence
Scale Jenkins by keeping the controller stable and making build agents replaceable.
Run zero executors on the controller
Delegate builds to agents so pipeline compilation/testing cannot starve the Jenkins control plane.
A modest ZimaBoard can remain a reliable controller even when agents are much larger.Put JENKINS_HOME and caches on SSD/NVMe
Plugin loading, configuration, workspaces, build logs and caches generate many small files. Responsive storage materially improves CI operations.
Use SATA SSD/NVMe rather than letting a large Jenkins history fill small eMMC.Use separate agent containers/VMs on the same physical server only for small labs
This preserves logical separation but not hardware failure isolation. Agent jobs still compete for the same CPU/RAM/storage.
ZimaBoard 2 1664 or ZimaCube 2 Pro provides more room for a home-lab controller plus agent.Scale agents by build type
Generic/fungible agents are a Jenkins best practice, but resource profiles should still fit the toolchain they execute.
Use stronger agent nodes for heavy compile/test workloads without inflating the controller.Can it run on ZimaOS?
Jenkins CI/CD is currently listed in the ZimaOS App Store under Developer.
Install Jenkins CI/CD from the ZimaOS App Store
Use the packaged Jenkins controller and persist JENKINS_HOME.
Open Jenkins CI/CD in the ZimaOS App StoreFollow current Java support policy
As of the 2026 Jenkins LTS line, Java 21/25 is the current supported runtime direction.
Read Jenkins Java support policyUse agents for builds
Jenkins' official hardware recommendations advise against controller executors and recommend delegating jobs to build machines.
Read Jenkins hardware recommendationsChoose Zima hardware for Jenkins CI/CD
Controller-only Jenkins is modest; build agents are where CPU, RAM and SSD capacity scale quickly.
Will the Zima host be only a Jenkins controller, or also run local build agents?
Controller-only / remote agents
ZimaBoard 2 832 comfortably exceeds the small controller floor and can support a small-team controller with disciplined retention.
- Controller-only JenkinsZimaBoard 2 832
- Larger controller / more developer servicesZimaBoard 2 1664
Controller plus local agents/caches
Use a stronger CPU and SSD storage, while keeping the agent logically separate from the controller.
- Integrated home-lab CI serverZimaCube 2 Pro
No fixed number of jobs, executors or builds-per-hour is guaranteed. Plugins, Java heap, build tools, parallelism, artifact retention and workspace caches can dominate resources.
| Zima hardware | Best for | Example workload | Core configuration | Recommended boundary | Next step |
|---|---|---|---|---|---|
| ZimaBoard 2 832 | A Jenkins controller with builds delegated to other agents. | Small-team orchestration, plugins, job configuration and build history. |
|
Do not run heavy build executors on the controller just because CPU/RAM is available. | Get Now |
| ZimaBoard 2 1664 | A larger Jenkins controller plus more developer services. | More plugins/jobs/users, larger Java heap and additional containers. |
|
The official architecture still favors external agents for real build work. | Get Now |
| ZimaCube 2 Pro | A home-lab CI server that also hosts separate local build agents and caches. | Controller plus Docker/VM agents, workspaces and larger SSD-backed build caches. |
|
Local agents share the same physical CPU/RAM/failure domain; heavy CI should eventually use separate agent machines. | Get Now |
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Frequently asked questions
FAQ topics follow query fan-out around 256 MB versus 4 GB, controller versus agent sizing, Java 21, executors and disk/caches. Community discussions are used to identify real CI confusion while Jenkins documentation defines architecture.
Does Jenkins really run with 256 MB RAM?
256 MB is the official installation minimum, but it is not a useful small-team target. Jenkins currently recommends 4 GB+ RAM for a small team, and plugin/job scale can push controller memory much higher.
Why does Jenkins say controller RAM can range from 200 MB to 70+ GB?
Because controller load depends on users, jobs, plugins, build history and connected nodes. Jenkins explicitly says there is no one-size-fits-all controller.
Should Jenkins builds run on the controller?
No for a well-designed setup. Jenkins calls controller executors a bad practice because builds can overload controller CPU/memory and cause unnecessary downtime.
How much RAM does a Jenkins build agent need?
There is no Jenkins-wide number. Agent RAM is determined by the build: Maven/Gradle, Node, Docker, Android, browser testing and other toolchains have very different requirements.
Why does Jenkins need 50 GB disk for a small team?
JENKINS_HOME accumulates plugins, job configuration, build history and logs, while local workspaces/caches can grow much faster. Jenkins lists 50 GB+ as a small-team recommendation rather than a hard minimum.
What Java version does Jenkins require in 2026?
Current Jenkins LTS 2.555.1+ supports Java 21 or Java 25. Older Jenkins lines had broader Java support, so runtime compatibility must be checked during upgrades.
Can ZimaBoard 2 832 run Jenkins?
Yes, especially as a controller with remote agents. Its 8 GB RAM exceeds Jenkins' small-team RAM recommendation, while SSD/SATA expansion is useful for JENKINS_HOME.
When should I choose ZimaCube 2 Pro for Jenkins?
When the same physical server also needs local agent VMs/containers, larger caches and faster storage. For scale and reliability, separate build-agent hardware remains the better architecture.
What sources and further reading informed this Jenkins hardware guide?
Jenkins' Linux installation and hardware-recommendation pages provide the 256 MB/1 GB floor, 4 GB/50 GB small-team guidance and controller-versus-agent architecture. The Java support policy defines current Java 21/25 support. Community discussions were used for query fan-out around controller sizing and agents, while ZimaOS confirms the current Developer app.
