Build yourself a Ubuntu kernel snap

Sample snapcraft.yaml for advanced users who want to rebuild the kernel from Ubuntu official kernel source.

Introduction

Supported Hardware:

1. Dell Edge Gateway 3001/3002/3003
2. Dell Edge Gateway 5000/5100

Target OS:

Ubuntu Core 16

Build Environment:

Ubuntu Desktop 16.04 64bit

Building a Custom Kernel - HowTo

Kernel source code

$ git clone git://kernel.ubuntu.com/ubuntu/ubuntu-xenial.git

Preparation

$ sudo apt-get update
$ sudo apt-get build-dep linux-image-$(uname -r)

Download sample files

$ git clone https://github.com/CragW/kernel-snap.git
$ cd kernel-snap

Build the kernel snap

$ sudo snapcraft

The time to finish the build depends on the configuration of build machine. At the end, kernel-x_4.x_amd64.snap will be generated in the same directory.

Notes

• Testing a custom built kernel snap requires switching off Secure Boot in the BIOS.
• No support/maintainence for custom built kernel snap.

Testing

On the supported hardware devices, check the current kerne1 snap revision:

$ snap list

For example: (The revision is 40)

Name                Version        Rev  Developer  Notes
caracalla-kernel    4.4.0-2002.2   40   canonical  -

Backup the r40 kernel snap

$ cp /var/lib/snapd/snaps/caracalla-kernel_40.snap ~/

Replace the current kernel snap with developing(custom built) kernel snap

$ sudo cp <name of devel kernel snap> /var/lib/snapd/snaps/caracalla-kernel_40.snap

Reboot the system and test the kernel

$ sudo reboot

Restore kernel snap

Copy back the original kernel snap

$ sudo cp ~/caracalla-kernel_40.snap /var/lib/snapd/snaps/caracalla-kernel_40.snap

Reboot the system

$ sudo reboot

OS Recovery

When things go wrong, you may factory restore the system entirely.