/docker-kvm

Docker and CoreOS files for running qemu

Primary LanguageShellMIT LicenseMIT

QEMU/KVM on Docker and CoreOS

Usage

  1. docker pull ianblenke/kvm
  2. docker run --privileged ianblenke/kvm /usr/bin/kvm QEMU_OPTIONS

Note that --privileged is required in order to run with the kernel-level virtualization (kvm) optimization.

Background

For the most part, it is fairly easy to run kvm within docker. The only real hiccup is that /dev/kvm (the device node for the kernel hypervisor access) isn't reissued (or permitted) within docker. That means we have to do two things for basic usage:

  1. Make the device node
  2. Execute the docker container with --privileged

While this is obviously not ideal, it isn't actually that bad, since you are running a full VM, in the container, which itself should isolate the client.

Why

Sometimes you need to orchestrate immutable windows instances, and Windows Server Containers aren't available yet.

Networking

The entrypoint script allows you to pass the $BRIDGE_IF environment variable. If set, it will add that bridge interface to the container's /etc/kvm/bridge.conf file which, in turn, allow your kvm instance to attach to that bridge using the built-in kvm-bridge-helper.

Note, however, that if you want to do this, you'll need to pass the --net=host option to your docker run command, in order to access the host's networking namespace.

Service file

Also included in this repo is a service file, suitable for use with systemd (CoreOS and fleet), provided as an example. You'll need to fill in your own values, of course, and customize it to your liking.