libvirt users - Sep 2013 - Re: Help needed in simulating libvirt

Hi,

Thanks for the response.

I've used the URI:
"test+ssh://<ipaddress>/default" and the connection is
successful and with
that connection I issued getCapabilities and its result is attached.
I'm not sure how is result xml generated by the files in the /examples
folder.
Will you please explain how is this xml generated.

Also my client is not going to modified. My client is going to connect with
the URI "qemu+tls://<host>/system?no_tty=1", so I can't
directly use the
test driver here so I need to replace the qemu driver with the test driver
and give my dummy response. So I need to know how to replace the driver say
qemu with test driver and generating my desired output.

If the test driver is not going to support me too much then I might want to
write new driver. Is there is any reference how to write new driver.

Regards,
Arun V


On Wed, Sep 11, 2013 at 2:23 PM, Daniel P. Berrange
<berrange@redhat.com>wrote:
> On Wed, Sep 11, 2013 at 12:50:37PM +0530, Arun Viswanath wrote:
> > Hi Eric,
> >
> > Thanks for your response.
> > I like to know how test driver works.
> >
> > In the libvirt.org for test driver it is mentioned as "It can
start
> with a
> > pre-configured default config, or be given a path to an alternate
> config".
> > Is the config is an xml file where we mentioned some dummy data so
that
> the
> > test driver will return it as response. If yes then where can I find
this
> > dummy file?
> >
> > As mentioned earlier my intention is to mock qemu calls. so it test
> driver
> > works then I'm planning to remove the qemu driver and register
"test"
> > driver as "qemu" driver and take the fake data from the
config file.
> Please
> > let me know which are the files I need to look into to register
"test" as
> > "qemu" and make its operations to work.
>
> The XML file is provided via the URI. For example
>
>    test:///default
>
> uses a built-in config, but you can supply a real path eg
>
>    test:///home/berrange/testnode.xml
>
>
> Take a look at examples/xml/test/testnode.xml  in the libvirt source
> tree for an example.
>
> FYI, the test driver is used very successfully in virt-install and
> virt-manager for testing their functionality in an automated way,
> so I can strongly recommend its use, over trying to mock the APIs
> or wire protocol yourself.
>
> Daniel
> --
> |: http://berrange.com      -o-   
http://www.flickr.com/photos/dberrange/:|
> |: http://libvirt.org              -o-            
http://virt-manager.org:|
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http://search.cpan.org/~danberr/:|
> |: http://entangle-photo.org       -o-      
http://live.gnome.org/gtk-vnc:|
>

On Wed, Sep 11, 2013 at 04:30:13PM +0530, Arun Viswanath
wrote:
> Hi,
> 
> Thanks for the response.
> 
> I've used the URI:
> "test+ssh://<ipaddress>/default" and the connection is
successful and with
> that connection I issued getCapabilities and its result is attached.
> I'm not sure how is result xml generated by the files in the /examples
> folder.
> Will you please explain how is this xml generated.
You write the XML yourself to describe the initiall characteristics of the
host scenario you are trying to simulate. eg the XML file describes what
guests you want to pre-create, the capabilities of the host, the storage
pools, storage volumes, etc, etc. The examples/xml/test directory shows
some illustrations of how todo this.
> Also my client is not going to modified. My client is going to connect with
> the URI "qemu+tls://<host>/system?no_tty=1", so I can't
directly use the
> test driver here so I need to replace the qemu driver with the test driver
> and give my dummy response. So I need to know how to replace the driver say
> qemu with test driver and generating my desired output.
Why can't you modify your client. It is pretty reasonable to have the
URI be configurable for any libvirt based app, so I don't see why this
should be a blocker.
> If the test driver is not going to support me too much then I might want to
> write new driver. Is there is any reference how to write new driver.
I don't see any compelling reason to create a new driver for the scenario
you are describing, and would likely reject any patches aiming to do so
based in the info you have provided so far.

Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|

Hi Daniel,

We are writing a scale test scenario for our client. So for the purpose of
scale test with the real code we can't request them to change the URI's,
so
not too much scope on changing the client.
Also we are having some simulated java object of Domain, hypervisor(kvm),
etc for which we have to populate the API Call response.

Our aim it to simulate one libvirt for more than one KVM hosts so that by
some way we will identify to which host particular call come and from that
java model we will populate the response.
So what I'm trying is to do is to create the initial xml from our java
object and then we will start the libvirt test driver. So on the driver
I'll try to find the host request and populate the response from the
particular xmls.

Any good reference or document about how to populate the test response will
be really helpful.
This is my entire scenario. Any idea or new approach is also really
appreciable.

Thanks In Advance,
Arun V




On Wed, Sep 11, 2013 at 4:39 PM, Daniel P. Berrange
<berrange@redhat.com>wrote:
> On Wed, Sep 11, 2013 at 04:30:13PM +0530, Arun Viswanath wrote:
> > Hi,
> >
> > Thanks for the response.
> >
> > I've used the URI:
> > "test+ssh://<ipaddress>/default" and the connection is
successful and
> with
> > that connection I issued getCapabilities and its result is attached.
> > I'm not sure how is result xml generated by the files in the
/examples
> > folder.
> > Will you please explain how is this xml generated.
>
> You write the XML yourself to describe the initiall characteristics of the
> host scenario you are trying to simulate. eg the XML file describes what
> guests you want to pre-create, the capabilities of the host, the storage
> pools, storage volumes, etc, etc. The examples/xml/test directory shows
> some illustrations of how todo this.
>
> > Also my client is not going to modified. My client is going to connect
> with
> > the URI "qemu+tls://<host>/system?no_tty=1", so I
can't directly use the
> > test driver here so I need to replace the qemu driver with the test
> driver
> > and give my dummy response. So I need to know how to replace the
driver
> say
> > qemu with test driver and generating my desired output.
>
> Why can't you modify your client. It is pretty reasonable to have the
> URI be configurable for any libvirt based app, so I don't see why this
> should be a blocker.
>
> > If the test driver is not going to support me too much then I might
want
> to
> > write new driver. Is there is any reference how to write new driver.
>
> I don't see any compelling reason to create a new driver for the
scenario
> you are describing, and would likely reject any patches aiming to do so
> based in the info you have provided so far.
>
> Daniel
> --
> |: http://berrange.com      -o-   
http://www.flickr.com/photos/dberrange/:|
> |: http://libvirt.org              -o-            
http://virt-manager.org:|
> |: http://autobuild.org       -o-        
http://search.cpan.org/~danberr/:|
> |: http://entangle-photo.org       -o-      
http://live.gnome.org/gtk-vnc:|
>