Re: [libvirt] [PATCH] storage pool discovery

On Mon, Aug 04, 2008 at 11:19:25AM +0200, Stefan de Konink wrote: > Daniel P. Berrange schreef: >> On Mon, Aug 04, 2008 at 11:02:33AM +0200, Stefan de Konink wrote: >>> On Mon, 4 Aug 2008, Daniel P. Berrange wrote: >>> >>>>> - - For iSCSI and related stuff everything was relatively easy, because >>>>> this would just mean to write the right /dev/blabla to the xenstore. >>>>> What is your idea to get different drivers working via: >>>>> virt://pool/volume (so basically blktap vs file vs disk) >>>> My idea was to have a script in /etc/xen/scripts/ >>> Me too, but in order to 'fetch' the actual configuration it is required to >>> contact libvirt. And query about the pool/volume location. In this way it >>> would be actually a 'redirection' to blktap or adding a devicepath. >>> >>> So this script is now written in plain C, but I want to know how you >>> imagine the driver selection based on connection uri. >> You can simply use xen:/// as the URI. There is no need for configurable >> URIs since thisis a xen specific script. > You don't get the issue. In order to run a specific script for example a > block device, it should have an unique prefix. That will make the > executable that is called so virt:// will call > /etc/xen/scripts/block-virt as script. > > As you might notice here, the common file://, tap:aio:// or psy:// is > not present, so if a pool is file based or device based it should some > how inform this 'script' how to redirect the parameters to the > appropriate script. This is what the <driver> tag in the XML can be used for. It can include a driver name (file, phys, tap) and subtype (raw, aio, qcow, etc). You just need to decide how to encode this info when passing it to Xend.