[Libguestfs] Standalone guestfs

[Richard W.M. Jones]

On Sat, Jun 01, 2013 at 10:05:20PM +0200, Gabriel wrote:
> On Sat, 01 Jun 2013 20:54:15 +0100, Richard W.M. Jones wrote:
> > On Sat, Jun 01, 2013 at 02:27:50PM +0000, Gabriel de Perthuis wrote:
> >> Hello,
> >> As I understand it guestfs appliances normally work as servers
> >> and run high-level commands from some external channel.
> >
> > This is the normal architecture when you're using libguestfs to access
> > a VM or disk image:
> >
> >   http://libguestfs.org/guestfs.3.html#architecture
> >
> >> But it might be possible to bundle a guestfish script to run
> >> commands from and do away with the external system.
> >> That would make it useful on non-virtualised systems.
> >
> > It's worth noting you can edit any device, including host devices
> > directly.  For example on my laptop:
> >
> > It's also possible to get libguestfs to connect to an arbitrary
> > socket, so-called 'libguestfs live'.  That could include a guestfsd
> > daemon running on the local host.  Run the daemon and set
> > LIBGUESTFS_BACKEND=unix:/path/to/some/socket
> >
> >   http://libguestfs.org/guestfs.3.html#backend
> >   https://rwmj.wordpress.com/2011/07/07/how-does-libguestfs-live-work/#content
> >
> > It would also be possible to run qemu-nbd or sshd on a physical
> > machine and access it using libguestfs (>= 1.22) from another machine.
> > Indeed this is a possible architecture under discussion for the new
> > version of virt-v2v.
> >
> > Hope that gives you some ideas.  If you have a specific use scenario
> > you are interested in, then please let us know.
> 
> I was thinking of running some operations on the root filesystem
> by kexec-rebooting into an appliance to get exclusive access.

I promise to look at this in more detail when I'm back at work next
week, but a quick question: where would the 'client' end of the
connection (ie. libguestfs) be running in this scenario?

> I would like to do something like that for my blocks tool
> (which does conversions to LVM and bcache).
> 
> https://github.com/g2p/blocks#readme

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org