Re: [Qemu-devel] Re: [RFC][PATCH v6 08/23] virtagent: add va.getfile RPC

[Anthony Liguori <aliguori@linux.vnet.ibm.com>]

On 01/25/2011 03:21 AM, Richard W.M. Jones wrote:
> On Mon, Jan 24, 2011 at 05:40:05PM -0600, Anthony Liguori wrote:
>    
>> BTW, how dependent is guestfsd on the guest that libguestfs uses?  I
>> wasn't even aware that it could be used outside of that context.
>>      
> The daemon is compiled separately -- separate ./configure, make, etc.
> You can run it on its own.
>
> On the other hand, it does need to talk to something on the other end
> of the virtio-serial guestfsd socket, and that other thing would
> usually be the libguestfs library ...
>
> One thing that Dan Berrange did was to patch[1] libguestfs so it could
> talk to any existing guestfsd (you pointed it at a Unix domain
> socket).  He was using this to write test regression tests for
> 'virt-install': ie. install a guest, put guestfsd inside it, then boot
> up the guest and check that everything was installed correctly by
> querying it from an external libguestfs.
>
> For various unrelated reasons these patches weren't quite ready to go
> upstream, but it's on our ROADMAP[2] to add something like this.
>
> In which case what you would do would be:
>
> (a) put guestfsd into existing guests
>    

How much infrastructure does guestfd depend on within the guest?  Do you 
need a full install with all of the bells and whistles or does it 
degrade cleanly when certain tools aren't available?

Regards,

Anthony Liguori

> (b) add a nice option to guestfish to attach to existing VMs, eg:
>
>    guestfish --attach Fedora14
>    [guestfish live attached to Fedora 14's virtio-serial guestfsd socket]
>    ><fs>  copy-in ./dirs /tmp/
>
>    "copy-in" would be dangerous currently if used on a live VM, but
>    in this case it would be quite safe
>
> (c) do the work of porting guestfsd to Windows, FreeBSD etc
>
> Rich.
>
> [1] https://www.redhat.com/archives/libguestfs/2010-July/msg00010.html
>      refined a bit more later on.
>
> [2] http://libguestfs.org/ROADMAP.txt
>    "* Allow alternate methods to start the appliance, including through
>       libvirt and by connecting to an existing appliance.  This was
>       originally planned for 1.8 but we didn't get patches in time."
>
>