Libguestfs - Nov 2013 - Re: Problem using virt-sysprep with RBD images

Hello Richard,

Thanks for the reply.

Indeed this behaviour exists in 1.25.6.

Grepping through the source [1], there are a number of files in
"./po/*.po[t]?" that contain this message, but I think it's
./src/drives.c
where the fail condition is actually detected / set.

On line 300 there is an if statement that checks the first character is a
slash:

  if (exportname[0] != '/') {
    error (g, _("rbd: image name must begin with a '/'"));
    return NULL;
  }


I tried to comment this out and recompile guestfs, but I get an error:

make[2]: Entering directory `/root/libguestfs-1.25.6/builder'
ocamlfind ocamlopt -g -warn-error CDEFLMPSUVYZX -package str,unix -I
../src/.libs -I ../ocaml -I ../mllib -package gettext-stub -c builder.ml -o
builder.cmx
File "builder.ml", line 53, characters 4-14:
Error: Unbound value List.iteri
make[2]: *** [builder.cmx] Error 2
make[2]: Leaving directory `/root/libguestfs-1.25.6/builder'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/root/libguestfs-1.25.6'
make: *** [all] Error 2

Can you provide some assistance resolving this compile error please?  Is
there perhaps a better place to pull the source from?

Thanks,
Jon A

[1]
http://libguestfs.org/download/1.25-development/libguestfs-1.25.6.tar.gz

On Tue, Nov 5, 2013 at 2:01 AM, Richard W.M. Jones
<rjones@redhat.com>wrote:
> On Mon, Nov 04, 2013 at 06:35:42PM -0700, Jon wrote:
> > Hello,
> >
> > I'm having a problem when trying to use virt-sysprep against vms
that
> have
> > rbd disk images.  When I run virt-sysprep I get the following error:
> >
> > >> root@kitt:~/libguestfs-1.22.4# virt-sysprep -d
server-clone-test
> > --firstboot firstboot.sh
> > >> Examining the guest ...
> > >> Fatal error: exception Guestfs.Error("rbd: image name
must begin with
> a
> > '/'")
> >
> > My Disk definition is as follows:
> >
> > >>     <disk type='network' device='disk'>
> > >>       <driver name='qemu'/>
> > >>       <source protocol='rbd'
name='libvirt-pool/server-clone-test'>
> > >>         <host name='192.168.0.40'
port='6789'/>
> > >>         <host name='192.168.0.35'
port='6789'/>
> > >>         <host name='192.168.0.2'
port='6789'/>
> > >>       </source>
> > >>       <target dev='hdb' bus='ide'/>
> > >>       <address type='drive' controller='0'
bus='0' target='0'
> unit='1'/>
> > >>     </disk>
> >
> > I can resolve this error by changing the name of the libvirt-pool:
> >
> > >>       <source protocol='rbd'
name='/libvirt-pool/server-clone-test'>
> >
> > But this causes an error when attempting to boot the vm:
> >
> > >> root@kitt:~/libguestfs-1.22.4# virsh start server-clone-test
> > >> error: Failed to start domain server-clone-test
> > >> error: internal error: process exited while connecting to
monitor: W:
> > kvm binary is deprecated, please use qemu-system-x86_64 instead
> > >> char device redirected to /dev/pts/5 (label charserial0)
> > >> qemu-system-x86_64: -drive
> >
>
file=rbd:/libvirt-pool/server-clone-test:auth_supported=none:mon_host=192.168.0.40\:6789\;192.168.0.35\:6789\;192.168.0.2\:6789,if=none,id=drive-ide0-0-1:
> > pool name too short
> > >> qemu-system-x86_64: -drive
> >
>
file=rbd:/libvirt-pool/server-clone-test:auth_supported=none:mon_host=192.168.0.40\:6789\;192.168.0.35\:6789\;192.168.0.2\:6789,if=none,id=drive-ide0-0-1:
> > could not open disk image
> >
>
rbd:/libvirt-pool/server-clone-test:auth_supported=none:mon_host=192.168.0.40\:6789\;192.168.0.35\:6789\;192.168.0.2\:6789:
> > Invalid argument
> >
> > I'm currently using libguestfs-1.22.4 and I did run into a known
bug [1]
> > that I was able to patch, but I don't think that's related to
the issues
> > with disk naming.
> >
> > Is there a way to give virt-sysprep a rbd with the -a flag, or is
there a
> > better way to sysprep vms?  I would like to avoid having to edit the
vm
> > config if possible.
>
> This is a bug basically.  I have filed a bug report here:
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1026688
>
> It would be helpful to try with a newer version of libguestfs.  Ubuntu
> has just pushed the 1.24.0 package.  I don't know if it'll help or
> not, but it would be useful to know if the behaviour changes.
>
>
>
https://launchpad.net/ubuntu/+source/libguestfs/1:1.24.0-0ubuntu1/+build/5181109
>
> Rich.
>
> --
> Richard Jones, Virtualization Group, Red Hat
> http://people.redhat.com/~rjones
> virt-p2v converts physical machines to virtual machines.  Boot with a
> live CD or over the network (PXE) and turn machines into KVM guests.
> http://libguestfs.org/virt-v2v
>

On Wed, Nov 06, 2013 at 11:17:14AM -0700, Jon wrote:
> I tried to comment this out and recompile guestfs, but I get an error:
> 
> make[2]: Entering directory `/root/libguestfs-1.25.6/builder'
> ocamlfind ocamlopt -g -warn-error CDEFLMPSUVYZX -package str,unix -I
> ../src/.libs -I ../ocaml -I ../mllib -package gettext-stub -c builder.ml -o
> builder.cmx
> File "builder.ml", line 53, characters 4-14:
> Error: Unbound value List.iteri
> make[2]: *** [builder.cmx] Error 2
> make[2]: Leaving directory `/root/libguestfs-1.25.6/builder'
> make[1]: *** [all-recursive] Error 1
> make[1]: Leaving directory `/root/libguestfs-1.25.6'
> make: *** [all] Error 2
Hmm, this is actually another bug :-(  The attached patch should fix
this one and allow you to compile libguestfs with the older version of
OCaml that didn't have List.iteri.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top

Hello Richard,

Haha, ok, here's a good one: I commented that if statement out at line 300,
applied your patch (I see you updated the github of this code, perhaps
that's the best place to grab the code from), and when I run virt-sysprep,
I get the following parameter for my disk drive:
>> qemu-system-x86_64: -drive
file=rbd:ibvirt-pool/server-clone-test:mon_host=192.168.0.40\:6789\;192.168.0.35\:6789\;192.168.0.2\:6789:auth_supported=none,cache=writeback,id=hd0,if=none:
error opening pool ibvirt-pool

Since "ibvirt-pool" doesn't exist. :)

So this says to me that the function "create_drive_non_file" is
consuming
that first slash somewhere.  Perhaps "safe_strdup"?  I'm not sure
where
"safe_strdup" is to confirm, but it looks like other functions use the
"safe_stardup" function.

With that in mind, I didn't want to have to reinvent create_drive_non_file,
and without a better understanding of how all the code works together, I
came up with a little hack which basically prepends the slash if there
isn't one.

  if (exportname[0] != '/') {
//    char name[(sizeof exportname) + 1];
    char name[256];
    snprintf(name, sizeof name, "/%s", exportname);
    exportname = name;
  }

My concern is long rbd-pool/rbd names, hence the commented out line, but
that causes the name of the disk to be:
>> qemu-system-x86_64: -drive
file=rbd:libvirt:mon_host=192.168.0.40\:6789\;192.168.0.35\:6789\;192.168.0.2\:6789:auth_supported=none,cache=writeback,id=hd0,if=none:
could not open disk image
rbd:libvirt:mon_host=192.168.0.40\:6789\;192.168.0.35\:6789\;192.168.0.2\:6789:auth_supported=none:
Invalid argument

For some reason, the commented out line in the if statement above is
truncating the end of the name.  Admittedly, my C skills are a bit rusty,
so I'm probably overlooking something obvious.

Any thoughts on this approach?

Thanks,
Jon A


On Wed, Nov 6, 2013 at 12:22 PM, Richard W.M. Jones
<rjones@redhat.com>wrote:
> On Wed, Nov 06, 2013 at 11:17:14AM -0700, Jon wrote:
> > I tried to comment this out and recompile guestfs, but I get an error:
> >
> > make[2]: Entering directory `/root/libguestfs-1.25.6/builder'
> > ocamlfind ocamlopt -g -warn-error CDEFLMPSUVYZX -package str,unix -I
> > ../src/.libs -I ../ocaml -I ../mllib -package gettext-stub -c
builder.ml-o
> > builder.cmx
> > File "builder.ml", line 53, characters 4-14:
> > Error: Unbound value List.iteri
> > make[2]: *** [builder.cmx] Error 2
> > make[2]: Leaving directory `/root/libguestfs-1.25.6/builder'
> > make[1]: *** [all-recursive] Error 1
> > make[1]: Leaving directory `/root/libguestfs-1.25.6'
> > make: *** [all] Error 2
>
> Hmm, this is actually another bug :-(  The attached patch should fix
> this one and allow you to compile libguestfs with the older version of
> OCaml that didn't have List.iteri.
>
> Rich.
>
> --
> Richard Jones, Virtualization Group, Red Hat
> http://people.redhat.com/~rjones
> virt-top is 'top' for virtual machines.  Tiny program with many
> powerful monitoring features, net stats, disk stats, logging, etc.
> http://people.redhat.com/~rjones/virt-top
>