Libguestfs - Nov 2013 - Re: HA: Accessing iSCSI disc images from the RHEV Manager using libguestfs

[CC to Fabian - can you comment on the ovirt-node problem below]

On Thu, Nov 21, 2013 at 10:02:46PM +0000, Исаев Виталий Анатольевич
wrote:
> On 11/21/2013 05:56 PM, Richard W.M. Jones wrote:
> > When you say "cannot access them" do you get an error
message?  Could
> > it be an SELinux denial?
> 
> Yes, when I am trying to open some logical volume on the hypervisor side,
for instance:
>     $ guestfish -a /dev/mapper/dm-xx
> libguestfs fails with an error message kind of that:
>     $ libguestfs-supermin-helper: failed to find a suitable kernel.
>     I looked for kernels in /boot and modules in /lib/modules.
>     If this is a Xen guest, and you only have Xen domU kernels
>     installed, try installing a fullvirt kernel (only for
>     libguestfs use, you shouldn't boot the Xen guest with it).
> So this is correct because hypervisor's file system is minimalist and
therefore contains
> kernel files neither in /boot nor in /lib/modules. 
Ah I see, this is a slightly different problem.  If this is RHEV-H /
ovirt-node then that's a bug in ovirt-node since it is supposed to
have a working libguestfs.

Can you paste the full, unedited output of:

  libguestfs-test-tool

on the hypervisor.
> And it is still not clear for me, how should I implement interaction
between the RHEV-M API,
> which tells me what logical volume (disk image) belongs to the every VM,
and the hypervisor's, to which
> all the logical volume (disk images) are mapped. 
> 
> So can I access the VM's disk images directly from the RHEV Manager in
case
> if manager, hypervisor and storage are different hosts? 
I'm not sure about this, but I guess the hooks that Itamar pointed to
before should work.

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

Rich, you are right; the hypervisor is RHEV-H. As Itamar has just explained me,
hooks are executed on the hypervisor’s side (not on the RHEV-M, as I used to
think), so properly working libguestfs on the RHEV-H will resolve my issue.

Here is the output of the test tool:



************************************************************

     *                    IMPORTANT NOTICE

     *

     * When reporting bugs, include the COMPLETE, UNEDITED

     * output below in your bug report.

     *

     ************************************************************

===== Test starts here ====
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

library version: 1.16.34rhel=6,release=2.el6

guestfs_get_append: (null)

guestfs_get_attach_method: appliance

guestfs_get_autosync: 1

guestfs_get_direct: 0

guestfs_get_memsize: 500

guestfs_get_network: 0

guestfs_get_path: /usr/lib64/guestfs

guestfs_get_pgroup: 0

guestfs_get_qemu: /usr/libexec/qemu-kvm

guestfs_get_recovery_proc: 1

guestfs_get_selinux: 0

guestfs_get_smp: 1

guestfs_get_trace: 0

guestfs_get_verbose: 1

host_cpu: x86_64

Launching appliance, timeout set to 600 seconds.

libguestfs: [00000ms] febootstrap-supermin-helper --verbose -f checksum
'/usr/lib64/guestfs/supermin.d' x86_64

supermin helper [00000ms] whitelist = (not specified), host_cpu = x86_64, kernel
= (null), initrd = (null), appliance = (null)

supermin helper [00000ms] inputs[0] = /usr/lib64/guestfs/supermin.d

febootstrap-supermin-helper: failed to find a suitable kernel.

I looked for kernels in /boot and modules in /lib/modules.

If this is a Xen guest, and you only have Xen domU kernels

installed, try installing a fullvirt kernel (only for

febootstrap use, you shouldn't boot the Xen guest with it).

libguestfs: error: cannot find any suitable libguestfs supermin, fixed or
old-style appliance on LIBGUESTFS_PATH (search path: /usr/lib64/guestfs)

libguestfs-test-tool: failed to launch appliance

libguestfs: closing guestfs handle 0x231d260 (state 0)



Thank you,

Vitaly Isaev



Виталий Исаев

Инженер-программист

Группа разработки и внедрения ПСЗИ

Департамент информационной безопасности

ОАО «Финтех»





-----Original Message-----
From: Richard W.M. Jones [mailto:rjones@redhat.com]
Sent: Friday, November 22, 2013 1:12 PM
To: Исаев Виталий Анатольевич
Cc: Itamar Heim; libguestfs@redhat.com; fdeutsch@redhat.com
Subject: Re: HA: [Libguestfs] Accessing iSCSI disc images from the RHEV Manager
using libguestfs



[CC to Fabian - can you comment on the ovirt-node problem below]



On Thu, Nov 21, 2013 at 10:02:46PM +0000, Исаев Виталий Анатольевич wrote:
> On 11/21/2013 05:56 PM, Richard W.M. Jones wrote:
> > When you say "cannot access them" do you get an error
message?
> > Could it be an SELinux denial?
>
> Yes, when I am trying to open some logical volume on the hypervisor side,
for instance:
>     $ guestfish -a /dev/mapper/dm-xx
> libguestfs fails with an error message kind of that:
>     $ libguestfs-supermin-helper: failed to find a suitable kernel.
>     I looked for kernels in /boot and modules in /lib/modules.
>     If this is a Xen guest, and you only have Xen domU kernels
>     installed, try installing a fullvirt kernel (only for
>     libguestfs use, you shouldn't boot the Xen guest with it).
> So this is correct because hypervisor's file system is minimalist and
> therefore contains kernel files neither in /boot nor in /lib/modules.


Ah I see, this is a slightly different problem.  If this is RHEV-H / ovirt-node
then that's a bug in ovirt-node since it is supposed to have a working
libguestfs.



Can you paste the full, unedited output of:



  libguestfs-test-tool



on the hypervisor.


> And it is still not clear for me, how should I implement interaction
> between the RHEV-M API, which tells me what logical volume (disk
> image) belongs to the every VM, and the hypervisor's, to which all the
logical volume (disk images) are mapped.
>
> So can I access the VM's disk images directly from the RHEV Manager in
> case if manager, hypervisor and storage are different hosts?


I'm not sure about this, but I guess the hooks that Itamar pointed to before
should work.



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 Fri, Nov 22, 2013 at 09:42:28AM +0000, Исаев Виталий Анатольевич
wrote:
> Rich, you are right; the hypervisor is RHEV-H. As Itamar has just
> explained me, hooks are executed on the hypervisor’s side (not on
> the RHEV-M, as I used to think), so properly working libguestfs on
> the RHEV-H will resolve my issue.
This is a bug.  I have filed this:

https://bugzilla.redhat.com/show_bug.cgi?id=1033508

If you have Red Hat Support it would be helpful if you could get them
to escalate this so it gets the right attention.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Fedora Windows cross-compiler. Compile Windows programs, test, and
build Windows installers. Over 100 libraries supported.
http://fedoraproject.org/wiki/MinGW