How to download linux kernel headers for Google container optimized OS

Question

I have to download kernel headers in 3 nodes in a Kubernetes cluster that is run on GKE. The nodes use Google's container optimized OS which appears to be a fork of Chromium OS.

How can I check if kernel headers are installed and where they are installed ? And how to install them if they are not already installed ? I tried using apt but it's not available in that OS.

Answer 1

a) As per the official doc:

The Container-Optimized OS from Google node images are based on a recent version of the Linux kernel and are optimized to enhance node security. A team at Google that can quickly patch images for security and iterate on features backs Container-Optimized OS images. The Container-Optimized OS images provide better support, security, and stability than other images.

b) As described in the doc:

In some cases, The agent may not install correctly if the nodes in your Kubernetes environment use Unix versions that do not match the headers provided. The kernel headers must be manually installed on each node in those circumstances

For RHEL-style distributions, run:

yum -y install kernel-devel-$(uname -r)

For more information on troubleshooting, refer to the Kernel Headers module

c) The below commands described in the doc will help you in validating the kernel header:

To check whether the kernel headers are installed (any user can run this):

$ yum list kernel-devel-$(uname -r)

To install the necessary kernel headers:

 $ sudo yum install -y kernel-devel-$(uname -r)

When properly installed, the required kernel headers are located under:

$ /usr/src/kernels/$(uname -r)/include/

Answer 2

It seems that there is no kernel headers available somewhere. However, you can build the kernel headers from source code.

1. Running in ubuntu or debian

2. Install required packages

apt-get -q update && apt-get -q install -y build-essential libncurses-dev bison flex libssl-dev libelf-dev bc dwarves cpio

2. Obtain build id from /etc/os-release inside a GKE node.

3. Download source code from cos cloud storage https://console.cloud.google.com/storage/browser/cos-tools.

mkdir /root/cos
cd /root/cos
mkdir /root/cos/kernel-src
mkdir /root/cos/kernel-headers
curl -sL https://storage.googleapis.com/cos-tools/$BUILD_ID/kernel-src.tar.gz --output kernel-src.tar.gz
tar -xf kernel-src.tar.gz -C /root/cos/kernel-src
curl -sL https://storage.googleapis.com/cos-tools/$BUILD_ID/kernel-headers.tgz --output kernel-headers.tgz
tar -xf kernel-headers.tgz -C /root/cos/kernel-headers

4. Use lakitu_defconfig, which is the default config for cos.

mkdir -p /root/cos/kernel-src/build-base
cp /root/cos/kernel-headers/usr/src/linux-headers-*/.config /root/cos/kernel-src/build-base/

cd /root/cos/kernel-src
make lakitu_defconfig O=build-base

5. Make all modules and headers

make O=build-base -j$(nproc)