schedctl

schedctl lets you run sched_ext-powered userspace schedulers packaged inside OCI images.

Installation

openSUSE Tumbleweed

schedctl is available in openSUSE Factory:

sudo zypper in schedctl

Arch Linux

schedctl is available on AUR, and you and install it using your favorite AUR helper:

paru -S schedctl

Container engine setup

Podman

In case you want to use Podman as your container engine of choice, you need to start the Podman socket to make sure schedctl can connect to it.

sudo systemctl start podman.socket

containerd

In case you want to use containerd as your container engine of choice, you just need to start the service.

sudo systemctl start containerd

Usage

Starting and stopping a scheduler using schedctl is trivial. Just identify the scheduler you want to run using schedctl list and then operate it using schedctl run and schedctl stop.

Simple as that. The tool will take care of downloading the scheduler and start the binary inside it.

Since containerized schedulers require extended capabilities, it's very likely that you'll need to run schedctl as root.

Development

schedctl is just a regular Go project, so just install make, go and you should be pretty much convered.

However, we have a couple things in the development workflow that are worth exploring.

QEMU rootfs

We run a significant portion of our integration tests in a QEMU virtual machine orchestrated by a testing library.

The QEMU rootfs is an Arch Linux disk image built with mkosi. The configuration lives in testdata/ (mkosi.conf, mkosi.repart/, mkosi.extra/, and mkosi.postinst.chroot).

In CI, the image is built on-the-fly by mkosi. To build it locally:

sudo mkosi --directory testdata --output-dir testdata

This produces testdata/rootfs.raw. Note that mkosi creates a GPT-partitioned disk image, so you'll need to extract the root partition for use with the test framework:

LOOP=$(sudo losetup --find --show --partscan testdata/rootfs.raw)
sudo dd if="${LOOP}p1" of=testdata/rootfs_ext4.raw bs=4M
sudo losetup -d "$LOOP"
mv testdata/rootfs_ext4.raw testdata/rootfs.raw
qemu-img create -o backing_file=rootfs.raw,backing_fmt=raw -f qcow2 testdata/rootfs.cow

Legacy method

The old testdata/prepare_disk_image.sh script can still be used with distrobox to build the image manually:

$ distrobox assemble create --file testdata/distrobox.ini
$ distrobox enter arch-bootstrap
$ cd testdata
$ ./prepare_disk_image.sh

QEMU kernel image

We also ship a pre-built kernel for tests. The configuration is in testdata/config.

To refresh the kernel image and build a new one, follow these steps:

$ distrobox assemble create --file testdata/distrobox.ini
$ distrobox enter arch-bootstrap
$ cd testdata
$ ./prepare_kernel_image.sh