[Libguestfs] Help: Is it possible to use libguestfs in Xen guest OS

[Richard W.M. Jones]

On Thu, Apr 07, 2016 at 10:12:07PM +0800, Baochuan Wu wrote:
> Hi All,
> 
> I installed CentOS 7 as Xen Guest OS(DomU OS), I wonder if it is possible
> to use libguestfs in this CentOS 7 VM? libguestfs-test-tools reports error:
[...]
> Original error from libvirt: internal error: process exited while
> connecting to monitor: Cannot set up guest memory 'pc.ram': Cannot allocate
> memory
[...]
> Cannot set up guest memory 'pc.ram': Cannot allocate memory
> libguestfs: error: appliance closed the connection unexpectedly, see
> earlier error messages

It looks as if you VM has very limited RAM, not enough to start up the
qemu instance.  If you give your VM more memory, then libguestfs
should work fine.  We run libguestfs nested all the time.

> After running "*export LIBGUESTFS_BACKEND=direct*", it seems libguestfs
> will launch another VM inside my VM. Is this necessary?

That's how libguestfs works:

  http://libguestfs.org/guestfs-internals.1.html

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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