🛠️ How I Fixed a Jenkins Build Issue on Amazon Linux After Kernel 6.12 Update

After a kernel upgrade from 5.10 to 6.12 on Amazon Linux, Jenkins builds stopped working on t2.micro EC2 instances. Turns out, it’s due to system monitor settings and limited instance resources. Here's how I fixed it.

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🐛 The Issue

After upgrading the kernel on my Amazon EC2 instance from 5.10 to 6.12, I noticed Jenkins jobs stopped running properly.

• Jenkins UI loaded fine.

• But clicking "Build Now" had no effect.

• No console logs, no errors — just… nothing.

This issue only occurred when running on a t2.micro instance.

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🔍 Discovery: Instance Type Matters

During testing, I tried the same setup on a t2.medium instance and everything worked perfectly.

✅ Switching to t2.medium resolved the issue without any configuration changes.

This made it clear that the issue was related to resource availability or system behavior introduced by kernel 6.12 on smaller EC2 instance types like t2.micro.

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🛠️ Fixing the Issue on t2.micro

If you’re restricted to using a t2.micro, you can still get Jenkins working by following these steps.

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✅ Step 1: Open Build Executor Status

In Jenkins Dashboard, go to:

Manage Jenkins → Build Executor Status

Click on your current node (usually "master").

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✅ Step 2: Configure Monitors

In the node configuration screen, click:

Configure → Configure Monitors

Enable the following system monitors:

• Disk Space

• Temporary Space

• Swap Space

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✅ Step 3: Provide Source Code and Build

I tested with a basic GitHub repository:

🔗 https://github.com/vinuthnak12/one.git

After configuring the monitors, I triggered the build — and it worked successfully!

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Finally, the build succeeded

🎯 Key Insights

• Kernel 6.12 introduces system-level changes that affect build behavior, especially on low-resource EC2 types like t2.micro.

• Jenkins builds may silently fail unless system monitors are explicitly enabled.

• Upgrading your instance to t2.medium or higher is a more reliable long-term solution.

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💡 Bonus: Works with Nexus and Tomcat Too

I also tested Nexus Repository Manager and Apache Tomcat on the same EC2 instance with kernel 6.12 — both worked flawlessly after the same monitor configuration.

Want a detailed blog on setting those up too? Let me know in the comments! 🙌

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🧠 Final Thoughts

Jenkins can be finicky when running on minimal cloud instances — especially after system updates like a kernel upgrade.

If you're facing similar issues:

• Check your instance type

• Look at executor status

• Enable necessary system monitors

And always test builds after making infrastructure changes. It might save you hours of debugging.

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