libvirtd

This is a simple container wrapping libvirtd.

Purpose

Instead of delivering libvirtd in a package, libvirtd is now delivered in a container. When running the container it will look like libvirtd is running on the host's namespace. But in fact it's running in a container.

This is similar to Atomic's 'system containers'.

You can use virsh on the host to access it.

To access libvirtd via TCP you still need to export the correct port.

Try with k8s

For convenience there is a daemon set definition which can be used with kubernetes.

Note: make sure that libvirtd is not running on the hosts of the k8s cluster.

Define the daemon set:

kubectl create -f libvirtd-ds.yaml

Now test on any host of the cluster:

virsh -c "qemu+tcp://127.0.0.1/system" capabilities

Try without k8s

Note: Make sure to not run libvirtd on the host.

Start the container

docker run \
  --name libvirtd \
  --rm \
  --net=host \
  --pid=host \
  --ipc=host \
  --user=root \
  --privileged \
  -v /:/host:Z \
  -it kubevirt/libvirtd:latest

Now, to verify, run, on the host:

virsh capabilities

Environment Variables

These environment variables can be passed into the container

• LIBVIRTD_DEFAULT_NETWORK_DEVICE: Set it to an existing device to let the default network point to it.

Notes

Considerations that need to be taken into account:

• The D-Bus socket is not exposed inside the container so firewalld cannot be notified of changes (also not every host system uses firewalld) so the following ports might need to be allowed in if iptables is not accepting input by default:

  • TCP 16509
  • TCP 5900->590X (depending on Spice/VNC settings of guest)

  To run this container with the dbus socket mounted, a host directory could be mounted as a data volume. e.g.:

  docker run
  --name libvirtd
  --rm
  --net=host
  --pid=host
  --ipc=host
  --user=root
  --privileged
  -v /:/host:Z
  -v /var/run/dbus/system_bus_socket:/var/run/dbus/system_bus_socket -it kubevirt/libvirtd:latest

  The example path used here could vary across different systems.