I have a need to be able to provide custom kernel command line args per VM instance at boot time. For example, if glance is storing a kernel and initrd pair associated with the Fedora installer, it is neccessary to also provide a command line arg to tell the installer where to download a kickstart automation script from, or where the install tree is located. While some of this data could be stored in glance as metadata properties against the 'kernel' image, some it is inherantly data that changes per VM instance spawned. Thus I need some way to provide it at 'nova boot' time. https://blueprints.launchpad.net/nova/+spec/custom-kernel-args http://wiki.openstack.org/LibvirtCustomKernelArgs Two approaches come to mind for me - Add an explicit 'kernel-args' parameter to the 'nova boot' command and corresponding REST/RPC APIs - Add a generic 'properties' dict parameter to the 'nova boot' command and corresponding REST/RPC APIs, and define a standard property name 'kernel-args'. I'm figuring the latter would be preferrable since it gives us an extensible framework for instance metadata. NB, this is separate from metadata that you can alrady provide to feed through to the cloud-init services via config-drive / metadata service. It is metadata intended for interpretation by Nova itself, where as the existing metadata is for interpretation by the guest OS. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|