How to build an image using a locally patched kernel

Users
1

Hi. I want to build an Ubuntu Jammy image, but instead of an upstream kernel, I want to use a kernel that I patched and compiled on my local machine. Is this possible through packer or do I have to build from scratch? If it is possible through packer can I get a reference to any resource which tells me how to do that?

2

Hi @anishnandhan03

I think it should be possible. Please check the script that allows you to specify a custom kernel. I believe that you just need to add information about your kernel to /curtin/CUSTOM_KERNEL

3

@troyanov Thanks for replying.

But doesn’t this script just install a kernel from Ubuntu repos?

4

Right. But nothing stops you from modifying it and injecting your custom kernel instead.

5

This script will be executed from within QEMU right?

6

Correct. Packer is using QEMU VM and thats where all the scripts preparing an image are executed.

  provisioner "shell" {
    environment_vars = [
      "CLOUDIMG_CUSTOM_KERNEL=${var.kernel}",
      "DEBIAN_FRONTEND=noninteractive"
    ]
    scripts = ["${path.root}/scripts/cloudimg/install-custom-kernel.sh"]
  }