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"?

Rich.