Nova/UML

If you want to play around with Nova in the cloud<<FootNote("Yo dawg, I heard you like clouds, so I put a cloud in your cloud..")>>, you can use user-mode-linux instead of KVM or Xen. Here's how:

Image

First of all, you need an image that can be run by UML. Grab an Ubuntu Lucid one here: http://nova.openstack.org/~soren/ubuntu-lucid-uml.img.gz

Bundle it up like you usually would:

wget http://nova.openstack.org/~soren/ubuntu-lucid-uml.img.gz
gzip -d ubuntu-lucid-uml.img.gz
euca-bundle -i ubuntu-lucid-uml.img
euca-upload-bundle -b uml-image-bucket -m /tmp/ubuntu-lucid-uml.img.manifest.xml
euca-register uml-image-bucket/ubuntu-lucid-uml.img.manifest.xml

This gives you back an AMI id. Nova doesn't (yet) understand that this is a UML image and thus doesn't need a separate kernel, so when you want to run it, you need to pass a kernel and ramdisk to euca-run-instances.

XML template

The XML template for UML is different than the one for KVM. Grab it here: http://nova.openstack.org/~soren/uml-template.xml

...and tell nova-compute to use this new template instead of the default one using the --libvirt_xml_template option.

libvirt URI

(Note: This functionality has not been merged in yet) Finally, you need to tell nova-compute to use the UML URI. You do this by passing "--libvirt_uri uml:///system" to it.

That should do the trick.