Jenkins Installation and Requirements

[Abdullah-0-3]

Describe your use-case which is not covered by existing documentation.

When you go to install Jenkins for any OS maybe Linux or Windows. The Installation is right on top. When you go down then it has the code to install Java. As Java is the requirement for Jenkins so Java should be on top or a link telling to go and run install Java.

As a teacher many student run the Jenkins command and say it is not running. Then, I have to tell them that you need to install Java down below.

I hope you take this into action. Thank You!

Muhammad Abdullah
+92 3095306826

Reference any relevant documentation, other materials or issues/pull requests that can be used for inspiration.

No response

Are you interested in contributing a fix?

No response

[welcome]

Thanks for opening your first issue for jenkins.io! We appreciate you taking the time to report this issue.

[krisstern]

@MarkEWaite @kmartens27 Would adding some instructions about the Java JDK requirement near the top of the Download page at https://www.jenkins.io/download/ suffice? If so I could follow up with a pull request.

[MarkEWaite]

I think that an opening section that alerts the reader that they need to install Java would be a good thing, but I would rather have that section be a series of links to installation instructions provided by the JDK distributors rather than us providing detailed installation steps. That opening section should reuse the phrasing from the Java Support Policy so that we're stating things consistently.

For example, we might remove the documentation that describes Debian/Ubuntu installation and place a Java alternatives section immediately within each of the operating system specific sections as the first item. That Java alternatives section for Debian/Ubuntu might say:

Java alternatives

Jenkins requires Java 17 or Java 21. Jenkins on Debian and Ubuntu is fully tested with

• OpenJDK JDK / JRE 17 - 64 bits
• OpenJDK JDK / JRE 21 - 64 bits

JRE/JDKs from other vendors are supported and may be used. Refer to our issue tracker for known Java compatibility issues. Jenkins maintainers actively test HotSpot based Java virtual machines like those from OpenJDK, Eclipse Temurin, and Amazon Corretto. Refer to their installation guides:

• Amazon Corretto 21 or Amazon Corretto 17
• Eclipse Temurin 21 or Eclipse Temurin 17
• Microsoft build of OpenJDK for Ubuntu or Debian

---

A similar section could be added for Red Hat distributions, Fedora distributions, and for Windows distributions, though the links would be different for each of the JDK providers.

P.S. I may be completely wrong on this idea, since we need to retain the fontconfig use for OpenJDK on Debian, Ubuntu, and Red Hat based installations. That's not generally covered by the installation instructions from the JDK providers.

[krisstern]

Thanks @MarkEWaite for the detailed feedback! Let me follow up with a PR over the next few days

[Lonwwolf14]

@Abdullah-0-3 @krisstern @MarkEWaite

Thank you, Abdullah, for raising this issue and to all for the insightful discussion. I propose a streamlined approach: adding a "Before You Install Jenkins" section at the top of https://www.jenkins.io/download/. Here’s a concise outline:

Before You Install Jenkins

Jenkins requires a compatible Java Development Kit (JDK). Prepare your system as follows:

1. Install Java 17 or 21 (64-bit)

   • Recommended options:
     • Amazon Corretto 21 or 17
     • Eclipse Temurin 21 or 17
     • Microsoft OpenJDK for Ubuntu or Debian

2. Verify Java

   • Run java -version to confirm Java 17 or 21.

3. Linux GUI Setup (if needed)

   • For graphical features (e.g., charts):
     • Ubuntu/Debian: sudo apt install fontconfig
     • Red Hat/Fedora: sudo dnf install fontconfig

Proceed to installation instructions once Java is configured.

This ensures:

• Java is immediately visible, avoiding oversight.
• fontconfig is retained per @MarkEWaite’s note (vendor guides omit it).

I’m happy to adjust or assist with testing if @krisstern’s PR aligns this way.

[krisstern]

Hi @Lonwwolf14 thanks for your suggestion, but I am working on a pull request following @MarkEWaite's suggestion instead.

[Lonwwolf14]

@krisstern

Thanks for the update! No worries, I appreciate you’re moving forward with @MarkEWaite’s suggestion. I still think a top-level "Before You Install Jenkins" section could make Java even more unmissable for newbies, but I’m happy to see this issue progressing either way.
Let me know if there’s anything I can do to help test or refine it!

[krisstern]

Hi @Lonwwolf14 I will come up with a solution as I am currently working on this. We have copy editors who will review and provide feedback later.

[krisstern]

Hi @StackScribe I meant to start this earlier but got delayed. However, I feel it could be one of the good first issues you are looking for so I am assigning it to you now.