Re: [Libguestfs] Can't access remote URI

On Thu, Dec 20, 2012 at 05:30:03PM +0800, Wanlong Gao wrote: > On 12/20/2012 05:08 PM, Richard W.M. Jones wrote: > > On Thu, Dec 20, 2012 at 04:00:10PM +0800, Wanlong Gao wrote: > >> Hi Rich, > >> > >> We just found that the libguestfs can't access the remote URI. > >> When doing guestfs__add_drive_opts(), we always add files from > >> local system, it's related the -c|--connect option. > >> > >> As I know, we are using local kernel to lunch the min-guest, > >> and it's hard to attach remote disks to our local min-guest. > >> > >> Our test team found this problem by using following command, > >> > >> # virt-sysprep -c qemu+ssh://<host>/system -d domname > >> > >> Then, for example the path of remote disk is /work/rhel.img, > >> but we are about to access the /work/rhel.img locally. > >> > >> So, IMHO, if we are about to not support the remote URI, we > >> should give a error message first. But access local disks > >> instead of remote disks are definitely wrong here. > >> > >> Maybe we also need document this. > >> > >> Any thoughts? > > > > John Eckersberg is working on implementing this for libguestfs 1.22. > > Most of the libvirt support has been done already, but there is some > > more libvirt and libguestfs work. > > > > As for reporting an error, it's difficult because libvirt doesn't give > > a simple way to find out if a URI is "remote" or not (whatever > > "remote" means). And even if libvirt did, it's not necessarily true > > that remote URIs wouldn't work, eg. if the user attached a LUN to both > > the remote and local machine. > > So, at this time, we should report a useful message to user but not just > fail without any thing. Right? I don't know how you can report a useful message, since it's not obvious if a libvirt URI is remote. eg. How about the URI "qemu+ssh://foo/session" where the hostname of the local machine is "foo.example.com"? Or the hostname is "bar.example.com" but the local DNS contains a PTR record "foo" -> "bar"?