Re: [Libguestfs] guestmount failing to mount a qcow image

On 12/08/2011 05:43 PM, Richard W.M. Jones wrote: > On Thu, Dec 08, 2011 at 04:49:08PM +0000, Pádraig Brady wrote: >> # guestmount --rw -a /tmp/disk -i /tmp/tmplFlBCc >> libguestfs: error: mount_options: mount_options_stub: /dev/root: No >> such file or directory > > This image works OK with libguestfs 1.14/1.15. I suspect the commit > you need to make it work is: > > commit 917f947590c92318fee2545ba88245d0de012e31 > Author: Richard W.M. Jones <rjones(a)redhat.com&gt; > Date: Fri Sep 16 15:26:20 2011 +0100 > > inspection: Handle /dev/root in /etc/fstab. > > This means "the device that holds /etc/fstab", so map it correctly. > > This fixes support for ttylinux and also some other guests that use > /dev/root instead of a real device name. > > The bigger issue here for OpenStack is how to recover gracefully when > inspection fails. Even though guestmount -i doesn't work on the older > libguestfs, you could still have used explicit -m option(s). Yep that works: `guestmount -a annoying.qcow2 -m /dev/sda mount_dir/` The awkward thing about the failure mode is that it warns, but returns EXIT_SUCCESS, leaving the dir "half mounted" (and then fusermount -u gives an EBUSY error (hmm I might use -z)) I'm tempted to assume an error if there is any output to stderr.

> You would have to know somehow which filesystem(s) are available and which > you want to modify. That is information you can get from the API > (g.list_filesystems) or using virt-filesystems. It's reasonable, if > there is only one filesystem in the image, to just mount that one. > What's less clear is what should happen if there are multiple > filesystems: that information would have to be passed down from the > user through OpenStack. There is a 'partition' variable passed through the api, I guess it could be 0 = /dev/sda, 1..N = /dev/sdaN, -1 => -i I'll sort something out.