On Mon, 2010-11-08 at 10:02 +0000, Daniel P. Berrange wrote:
On Fri, Nov 05, 2010 at 02:04:50PM -0500, Jamie Strandboge wrote:>
This is confirmed as not working on 0.8.3 and 0.8.5. The attached patch against 0.8.5 fixes the issue and restores host_device support.
host_device is not a data format type, but rather a qemu driver protocol. As such it is not applicable for the <driver type=XXX> field, because the protocol is already specified at the <disk> element level with a combo of the type+device fields. If it happened to be possible to set it in the <driver> field that is just pure chance & not something that is supported. If we need to setup host_device anywhere, then this needs to be dealt with at the qemu_conf.c where we generate the CLI args.
Hmm... that is not clear in the documention IMHO (and the patch was careful to only use this for the qemu driver). Eg from the qemu-img man page: "Supported image file formats: raw ... host_device ... qcow2 ... ... " Ie, the language in the qemu-img man page has 'host_device' at the same level as 'raw', 'qcow2', 'cow', etc as a 'file format'. http://libvirt.org/formatdomain.html#elementsDisks only talks about a 'sub-type' for the qemu driver (but it is easy to infer that it is looking at the qemu-img types after using libvirt for a while) and http://libvirt.org/storage.html does not list 'host_device' as a 'format type', but it does list all of the other ones from the same section of the qemu-img man page (except 'vdi', which is maybe an omission in the libvirt docs?). Finally, 'man virsh' does list 'host_device' as a 'file format' in its 'vol-create-as' command. By all means if this needs to be cleaned up in qemu_conf.c that seems fine, but until then I feel that either host_device should be supported again (preferred based on the qemu-img man page) or the documentation made more consistent, and something probably added in http://libvirt.org/news.html for people upgrading to 0.8.3 or later since libvirt users are hitting this. -- Jamie Strandboge | http://www.canonical.com