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

On 11/22/2013 10:26 AM, Исаев Виталий Анатольевич wrote:
> Thanks, Itamar. Hooks are really great tool.
> No doubt we will use them.
>
> But I still need some clarification about interaction between hooks (on the
manager's side) and libguestfs (on the side of hypervisor/storage).
these are vdsm-hooks, they run on the host, not on the engine (manager).
the engine does allow you, if you want, to configure which custom 
properties can be defined at the VM level for example.
then you could make this check optional, or allow to override it.
say your default is to perform the check.
you can add a UserDefinedCustomProperty of "ByPassImageCheck" that can
accept value of 'true'.
then if you want to bypass this check for a sepcific VM, you will set 
this custom property for that VM (your hook should have an "if 
!ByPassImageCheck" logic in it of course.

(we have other types of hooks for engine side, and uiplugins to embed 
things in the gui).

My I ask for the bigger picture of what you are trying to do?

thanks,
    Itamar

>
> Виталий Исаев
> Инженер-программист
> Группа разработки и внедрения ПСЗИ
> Департамент информационной безопасности
> ОАО <Финтех>
>
>
> -----Original Message-----
> From: Itamar Heim [mailto:iheim@redhat.com]
> Sent: Friday, November 22, 2013 2:09 AM
> To: Исаев Виталий Анатольевич; Richard W.M. Jones
> Cc: libguestfs@redhat.com
> Subject: Re: HA: [Libguestfs] Accessing iSCSI disc images from the RHEV
Manager using libguestfs
>
> On 11/22/2013 12:02 AM, Исаев Виталий Анатольевич wrote:
> ...
>>> i may be missing something, but wouldn't vdsm hooks be a better
fit:
>>> http://www.ovirt.org/VDSM-Hooks
>>>
>>> for example, I think the "checkimages" one would cover
what you are
>>> trying to do already?
>>
>> Thank you, this hook was useful, but "gemu-img check" command
is
>> slightly different from our purposes, because we are trying to prevent
the booting from disk image with changed system binaries.
>
> I'll leave the rest to rich, but on this last one:
> you can implement any logic you want in a hook, including the libguestfs
one. it just removes the need to listen on rhev-m events iiuc.
>
>>
>>> http://gerrit.ovirt.org/gitweb?p=vdsm.git;a=tree;f=vdsm_hooks;
>>>
>>> you can also ask such questions on users@ovirt.org.
>>
>> Thank you for your attention and advises.
>> Vitaly
>>
>

On Fri, Nov 22, 2013 at 11:11:32AM +0200, Itamar Heim
wrote:
> My I ask for the bigger picture of what you are trying to do?
See:
https://www.redhat.com/archives/libguestfs/2013-November/msg00059.html

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.
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On 11/22/2013 11:50 AM, Richard W.M. Jones wrote:
> On Fri, Nov 22, 2013 at 11:11:32AM +0200, Itamar Heim wrote:
>> My I ask for the bigger picture of what you are trying to do?
>
> See:
> https://www.redhat.com/archives/libguestfs/2013-November/msg00059.html
>
> Rich.
>
please note for ovirt-node/rhev-, custom hooks would also need 
persisting (I don't recall if they are formally supported actually).

once you write the code as a custom hook for a RHEL node, you could 
discuss merging it as a full blown feature at arch@ovirt.org, then it 
won't be an issue and you won't need custom hooks, etc.