[libvirt] libguestfs integration: rich disk access for libvirt applications

[Stefan Hajnoczi]

Libguestfs provides very nice functionality for applications that need
to work with disk images.  The includes provisioning applications that
set up or customize disk images.  It also includes backup applications
that want to look inside disk image snapshots - both at the block and
file level.

What's missing for libguestfs to fill this role is integration that
allows libvirt and libguestfs to work together with the same
network-transparent remote API approach.

In the past we have discussed remoting libguestfs and Richard
presented possible approaches:
https://www.redhat.com/archives/libguestfs/2011-May/msg00093.html

Could libvirt could provide a secure channel over which the libguestfs
client that an application is linked against talks to the remote
guestfsd?

Would libguestfs need some new parameters to connect to a remote
libvirtd and create its appliance VM?

In terms of application use cases, I'm thinking along the lines of
using libvirt to enumerate storage volumes and then switching to
libguestfs to actually access the storage volume remotely.  Is there
enough information exposed by libvirt today to switch over to
libguestfs and point it at the storage volume/image file?

Stefan