Xen devel - Oct 2005 - App virtualisation, not OS virtualisation

I would like to run multiple copies of an application on a PC with 
multiple remote dumb clients.

It would seem to me that running Xen would be a sub-optimal solution as 
I would need a copy of the OS running for every copy of the application, 
but I was wondering whether a subset of Xen or Xen techniques could be used.

There are 2 barriers to running multiple applications with remote access:

- the application may check to see if a copy is already running and 
block a second copy starting up;

- how to feed mouse / keyboard input to the relevant copy of the 
application.

I''d like to be able to do this on Windows XP and am happy to wait for 
the next Intel / AMD chips with virtualisation support if that helps.

Any pointers would be gratefully appreciated.

Regards

Graham


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On 10/20/05, graham <graham@t5labs.com> wrote:
> I would like to run multiple copies of an application on a PC with
> multiple remote dumb clients.
Sounds like something better handled with LTSA, VNC or NX.

With unix you can native run several copies of the same application at
the same time. With X11 you can even do so from multiple locations.


Xen however is very useful for running the domain that might serve
such applications.


--
Nicholas Lee
http://stateless.geek.nz
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>>I would like to run multiple copies of an application on a PC with
>>multiple remote dumb clients.
>>    
>>
>
>Sounds like something better handled with LTSA, VNC or NX.
>  
>
VNC just provides remote access to the main keyboard / mouse queue and 
the transmission of the display.

I already have a solution for remote access but my problems are:

- I want to have several copies of an application running, each with a 
remote user. How do I pass the keyboard / mouse data to the right 
application if there is only one Windows message queue?

- on start up an application normally checks to see if a copy of itself 
is already running and if it is, it stops loading itself.

If the NX you are referring to is Linux terminal server then that''s no 
use because:

- it doesn''t solve the two problems I mentioned above

- it is a Linux product and as I previously said, I need a solution with 
Windows XP.

I don''t know LTSA can you give me a URL?
>With unix you can native run several copies of the same application at
>the same time. With X11 you can even do so from multiple locations.
>  
>
Fine, but as I said, I need a solution for Windows XP.
>
>Xen however is very useful for running the domain that might serve
>such applications.
>  
>
Well that was my original question. As I understand it, Xen has been 
designed to act as an encapsulation of the OS so that several copies / 
versions of OS can be run. But it seems a waste of memory (and licence 
fee?) if I need a complete copy of Windows XP for each copy of the 
application I want to run. I was wondering whether Xen, or a part of Xen 
could run on top of Windows XP to encapsulate just the application 
instead, so that I could run multiple copies of the application but just 
one copy of the OS.

g.



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On 10/21/05, graham <the_ether@lycos.co.uk> wrote:
> - it is a Linux product and as I previously said, I need a solution with
> Windows XP.
If you need to use a WinXP server then Xen can''t help you at the
moment. Maybe look at Windows Terminal Service.
> I don''t know LTSA can you give me a URL?
Sorry, I meant LTSP.  Linux Terminal Server Project.

> could run on top of Windows XP to encapsulate just the application
http://wiki.xensource.com/xenwiki/XenFaq#head-fcb85a149da66907086cc8ba4f0793ad01769b92

Note, regardless encapsulating the application is not a
system/kernel/Xen level thing.  Its something managed by the OS.

Xen is unlikely to every "encapsulate applications".

Running multiple clients/applications from one server is call Thin
Client technology.  On Windows you need WTS:

http://www.google.com/search?lr=&ie=UTF-8&oe=UTF-8&q=Windows%20Terminal%20Services

--
Nicholas Lee
http://stateless.geek.nz
gpg 8072 4F86 EDCD 4FC1 18EF  5BDD 07B0 9597 6D58 D70C

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> - I want to have several copies of an application running, each with a
> remote user. How do I pass the keyboard / mouse data to the right
> application if there is only one Windows message queue?
Sadly, I don''t have much to suggest here but I''m not a Windows
person...
Thought of getting a more expensive Windows which allows multiple RDP 
connections?  That''ll probably really hurt the wallet, though...
> If the NX you are referring to is Linux terminal server then
that''s no
> use because:
>
> - it doesn''t solve the two problems I mentioned above
Well, separate NX login sessions *ought* to solve both problems but
it''ll only
work for Linux apps *unless* your app is friendly enough to run under Wine 
(might be worth a try).
> Well that was my original question. As I understand it, Xen has been
> designed to act as an encapsulation of the OS so that several copies /
> versions of OS can be run. But it seems a waste of memory (and licence
> fee?) if I need a complete copy of Windows XP for each copy of the
> application I want to run
I can''t remember what the MS position is on licensing virtual machines
these
days.
> I was wondering whether Xen, or a part of Xen 
> could run on top of Windows XP to encapsulate just the application
> instead, so that I could run multiple copies of the application but just
> one copy of the OS.
Not really: Xen is extremely oriented towards encapsulating operating systems.  
Encapsulating an application (whilst useful) is too "high level" for
Xen;
it''s really a separate problem space, since it''d basically
share no code in
common with Xens current functionality.

Unfortunately, there appear to be fewer means of encapsulating apps on Windows 
than Linux anyhow - there''s the separate RDP logins approach, or you
may find
there''s a commercial "jail" system for Windows (I thought
Virtuozzo used to
have something for this but I think they dropped it...).  There''s also
the
various third party login solutions like Citrix, etc.  Other than that I 
don''t have any ideas...

HTH,
Mark
> g.
>
>
>
> _______________________________________________
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> http://lists.xensource.com/xen-devel
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On 10/21/05, Mark Williamson <mark.williamson@cl.cam.ac.uk>
wrote:
> > - I want to have several copies of an application running, each with a
> > remote user. How do I pass the keyboard / mouse data to the right
> > application if there is only one Windows message queue?
>
> Sadly, I don''t have much to suggest here but I''m not a
Windows person...
> Thought of getting a more expensive Windows which allows multiple RDP
> connections?  That''ll probably really hurt the wallet, though...
>
> > If the NX you are referring to is Linux terminal server then
that''s no
> > use because:
> >
> > - it doesn''t solve the two problems I mentioned above
>
> Well, separate NX login sessions *ought* to solve both problems but
it''ll only
> work for Linux apps *unless* your app is friendly enough to run under Wine
> (might be worth a try).
>
> > Well that was my original question. As I understand it, Xen has been
> > designed to act as an encapsulation of the OS so that several copies /
> > versions of OS can be run. But it seems a waste of memory (and licence
> > fee?) if I need a complete copy of Windows XP for each copy of the
> > application I want to run
>
> I can''t remember what the MS position is on licensing virtual
machines these
> days.
>
> > I was wondering whether Xen, or a part of Xen
> > could run on top of Windows XP to encapsulate just the application
> > instead, so that I could run multiple copies of the application but
just
> > one copy of the OS.
>
> Not really: Xen is extremely oriented towards encapsulating operating
systems.
> Encapsulating an application (whilst useful) is too "high level"
for Xen;
> it''s really a separate problem space, since it''d
basically share no code in
> common with Xens current functionality.
On a sort of related note, I was wondering if it was on any roadmap to
support RAM sharing between OS instances -- like with VMware''s clone
feature (or something like that), I think if you had two very similar
VMs, they would actually use less RAM and disk than each have, they
would just diverge where they are different (some sort of
copy-on-write scheme).

Thanks

>
> Unfortunately, there appear to be fewer means of encapsulating apps on
Windows
> than Linux anyhow - there''s the separate RDP logins approach, or
you may find
> there''s a commercial "jail" system for Windows (I
thought Virtuozzo used to
> have something for this but I think they dropped it...).  There''s
also the
> various third party login solutions like Citrix, etc.  Other than that I
> don''t have any ideas...
>
> HTH,
> Mark
>
> > g.
> >
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xensource.com
> > http://lists.xensource.com/xen-devel
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>
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>>>e OS.
>>>      
>>>
>>Not really: Xen is extremely oriented towards encapsulating operating
systems.
>>Encapsulating an application (whilst useful) is too "high
level" for Xen;
>>it''s really a separate problem space, since it''d
basically share no code in
>>common with Xens current functionality.
>>    
>>
>
>On a sort of related note, I was wondering if it was on any roadmap to
>support RAM sharing between OS instances -- like with VMware''s
clone
>feature (or something like that), I think if you had two very similar
>VMs, they would actually use less RAM and disk than each have, they
>would just diverge where they are different (some sort of
>copy-on-write scheme).
>
>Thanks
>  
>
Yes, that would solve my concern about wasted resource of having 
multiple copies of the same OS when all I want to do is run multiple apps.

In my case, I don''t mind waiting 6 months for the
virtualisation-enabled
AMD or Intel processors to be available.

BTW, in my case I intend using Windows XP embedded which, amongst other 
things, will allow me to reduce the footprint of the Windows OS. I am 
assuming that there shouldn''t be any problems with that with the
current
plans for Xen supporting Windows (?).

g.



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More like fork than memmerge:


www.cs.ucsd.edu/~savage/papers/Sosp05.pdf<http://www.cs.ucsd.edu/~savage/papers/Sosp05.pdf>


> On a sort of related note, I was wondering if it was on any roadmap to
> support RAM sharing between OS instances -- like with VMware's clone
> feature (or something like that), I think if you had two very similar
> VMs, they would actually use less RAM and disk than each have, they
> would just diverge where they are different (some sort of
> copy-on-write scheme).
>
> Thanks
>
>
> >
> > Unfortunately, there appear to be fewer means of encapsulating apps on
> Windows
> > than Linux anyhow - there's the separate RDP logins approach, or
you may
> find
> > there's a commercial "jail" system for Windows (I
thought Virtuozzo used
> to
> > have something for this but I think they dropped it...). There's
also
> the
> > various third party login solutions like Citrix, etc. Other than that
I
> > don't have any ideas...
> >
> > HTH,
> > Mark
> >
> > > g.
> > >
> > >
> > >
> > > _______________________________________________
> > > Xen-devel mailing list
> > > Xen-devel@lists.xensource.com
> > > http://lists.xensource.com/xen-devel
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@lists.xensource.com
> > http://lists.xensource.com/xen-devel
> >
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
>

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> Yes, that would solve my concern about wasted resource of 
> having multiple copies of the same OS when all I want to do 
> is run multiple apps.
OSes are pretty small compared to the apps that get run in them, so its
not as big a win as you might think...

Ian

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