Loading kernel modules

Since RancherOS v0.8, we build our own kernels using an unmodified kernel.org LTS kernel. We also build almost all optional extras as modules - so most in-tree modules are available in the kernel-extras service.

If you do need to build kernel modules for RancherOS, there are 4 options:

  • Try the kernel-extras service
  • Ask us to add it into the next release
  • If its out of tree, copy the methods used for the zfs and open-iscsi services
  • Build it yourself.

Try the kernel-extras service

We build the RancherOS kernel with most of the optional drivers as kernel modules, packaged into an optional RancherOS service.

To install these, run:

sudo ros service enable kernel-extras
sudo ros service up kernel-extras

The modules should now be available for you to modprobe

Ask us to do it

Open a GitHub issue in the https://github.com/rancher/os repository - we’ll probably add it to the kernel-extras next time we build a kernel. Tell us if you need the module at initial configuration or boot, and we can add it to the default kernel modules.

Copy the out of tree build method

See https://github.com/rancher/os-services/blob/master/z/zfs.yml and https://github.com/rancher/os-services/tree/master/images/20-zfs

The build container and build.sh script build the source, and then create a tools image, which is used to “wonka.sh” import those tools into the console container using docker run

Build your own.

As an example I’m going build the intel-ishtp hid driver using the rancher/os-zfs:<version> images to build in, as they should contain the right tools versions for that kernel.

sudo docker run --rm -it --privileged -v $(pwd):/data -w /data rancher/os-zfs:$(ros -v | cut -d ' ' -f 3) bash

apt-get update
apt-get install -qy libncurses5-dev bc libssh-dev
curl -SsL -o src.tgz https://github.com/rancher/os-kernel/releases/download/v$(uname -r)/linux-$(uname -r)-src.tgz
tar zxvf src/tgz
zcat /proc/config.gz >.config
# Yes, ignore the name of the directory :/
cd v*
# enable whatever modules you want to add.
make menuconfig
# I finally found an Intel sound hub that wasn't enabled yet
make modules SUBDIRS=drivers/hid/intel-ish-hid

# test it
insmod drivers/hid/intel-ish-hid/intel-ishtp.ko
rmmod intel-ishtp

# install it
cp drivers/hid/intel-ish-hid/*.ko /lib/modules/4.9.45-rancher/kernel/drivers/hid/

# done

Then in your console, you should be able to run

modprobe intel-ishtp