[Qemu-devel] Qemu sandbox for teaching

[Qemu-devel] Qemu sandbox for teaching

[Jerome Warnier]

Does someone here have an idea on how to do the following using Qemu,
but I'm open to other suggestions:

I would like to provide a UNIX CLI sandbox for users to poke around in a
UNIX course. It would be better if available from the web (preferably
without having to install anything on the users' PC), and Free (as in
free speach).
The problem is that I need to give them root access, or at least a
simulation.
It would be even better if we could for instance install RedHat in it,
but it's not really required.

Thanks
-- 
Jerome Warnier <jwarnier@beeznest.net>
BeezNest

Re: [Qemu-devel] Qemu sandbox for teaching

[Paul Brook]

On Saturday 28 May 2005 13:42, Jerome Warnier wrote:
> Does someone here have an idea on how to do the following using Qemu,
> but I'm open to other suggestions:
>
> I would like to provide a UNIX CLI sandbox for users to poke around in a
> UNIX course. It would be better if available from the web (preferably
> without having to install anything on the users' PC), and Free (as in
> free speach).
> The problem is that I need to give them root access, or at least a
> simulation.
> It would be even better if we could for instance install RedHat in it,
> but it's not really required.

It's not really answering your question, but qemu is probably OTT for this. If 
I was setting this up I'd use UML and a java web based telnet/ssh client.

Paul

Re: [Qemu-devel] Qemu sandbox for teaching

[Jerome Warnier]

Le samedi 28 mai 2005 à 14:13 +0100, Paul Brook a écrit :
> On Saturday 28 May 2005 13:42, Jerome Warnier wrote:
> > Does someone here have an idea on how to do the following using Qemu,
> > but I'm open to other suggestions:
> >
> > I would like to provide a UNIX CLI sandbox for users to poke around in a
> > UNIX course. It would be better if available from the web (preferably
> > without having to install anything on the users' PC), and Free (as in
> > free speach).
> > The problem is that I need to give them root access, or at least a
> > simulation.
> > It would be even better if we could for instance install RedHat in it,
> > but it's not really required.
> 
> It's not really answering your question, but qemu is probably OTT for this. If 
> I was setting this up I'd use UML and a java web based telnet/ssh client.
Well, I was thinking about what the snapshot feature of qemu could bring
me.

In fact, I thought about the following solutions:
- qemu (or whatever other virtualization system)
- chroot (or specifically dchroot in Debian) and remote telnet or ssh
access
- UML

Advantages of every solution:
- qemu virtualizes a complete machine, which means installation of an OS
is possible and it is pretty safe (security-wise) to setup
- chroot is fast to run and pretty safe
- UML is fast to run and pretty safe

Problems of every solution:
- qemu is slow, and a lot of virtual machines at the same time on the
same machine will slow it down and use too much memory, I think (I'm
talking about 10 people «playing» at the same time). Using only a
text-mode virtual machine may probably help, though
- chroot does not allow much and may take time to setup correctly
- UML is difficult to setup, and needs a kernel patch (even on 2.6?) to
work


> Paul
-- 
Jerome Warnier <jwarnier@beeznest.net>
BeezNest

Re: [Qemu-devel] Qemu sandbox for teaching

[Herbert Poetzl]

On Sat, May 28, 2005 at 07:50:53PM +0200, Jerome Warnier wrote:
> Le samedi 28 mai 2005 à 14:13 +0100, Paul Brook a écrit :
> > On Saturday 28 May 2005 13:42, Jerome Warnier wrote:
> > > Does someone here have an idea on how to do the following using Qemu,
> > > but I'm open to other suggestions:
> > >
> > > I would like to provide a UNIX CLI sandbox for users to poke around in a
> > > UNIX course. It would be better if available from the web (preferably
> > > without having to install anything on the users' PC), and Free (as in
> > > free speach).
> > > The problem is that I need to give them root access, or at least a
> > > simulation.
> > > It would be even better if we could for instance install RedHat in it,
> > > but it's not really required.
> > 
> > It's not really answering your question, but qemu is probably OTT for this. If 
> > I was setting this up I'd use UML and a java web based telnet/ssh client.
> Well, I was thinking about what the snapshot feature of qemu could bring
> me.
> 
> In fact, I thought about the following solutions:
> - qemu (or whatever other virtualization system)
> - chroot (or specifically dchroot in Debian) and remote telnet or ssh
> access
> - UML
> 
> Advantages of every solution:
> - qemu virtualizes a complete machine, which means installation of an OS
> is possible and it is pretty safe (security-wise) to setup
> - chroot is fast to run and pretty safe
> - UML is fast to run and pretty safe
> 
> Problems of every solution:
> - qemu is slow, and a lot of virtual machines at the same time on the
> same machine will slow it down and use too much memory, I think (I'm
> talking about 10 people «playing» at the same time). Using only a
> text-mode virtual machine may probably help, though
> - chroot does not allow much and may take time to setup correctly
> - UML is difficult to setup, and needs a kernel patch (even on 2.6?) to

you might want to have a look at linux-vserver

	http://linux-vserver.org/

it allows you to have VPS with certain root rights
on a shared host, in a secure manner (no overhead)

HTH,
Herbert

> work
> 
> 
> > Paul
> -- 
> Jerome Warnier <jwarnier@beeznest.net>
> BeezNest
> 
> 
> 
> _______________________________________________
> Qemu-devel mailing list
> Qemu-devel@nongnu.org
> http://lists.nongnu.org/mailman/listinfo/qemu-devel

Re: [Qemu-devel] Qemu sandbox for teaching

[Henrik Nordstrom]

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On Sat, 28 May 2005, Jerome Warnier wrote:

> Advantages of every solution:
> - UML is fast to run and pretty safe

If you give out root rights UML is only as safe as the account the UML 
kernel runs as.

> Problems of every solution:
> - qemu is slow, and a lot of virtual machines at the same time on the
> same machine will slow it down and use too much memory, I think (I'm
> talking about 10 people «playing» at the same time). Using only a
> text-mode virtual machine may probably help, though

Only text-mode helps a lot.

> - chroot does not allow much and may take time to setup correctly

chroot and allowing root rights is a no-no. The root user within a chroot 
is still root.

> - UML is difficult to setup, and needs a kernel patch (even on 2.6?) to
> work

UML doesn't require a kernel patch but it performs significantly better 
if you do.

Similar for qemu with it's kqemu kernel module, but here only a custom 
module is required no patching of the main kernel.

I would go for qemu (with kqemu), tun/tap networking with proxy-arp or 
explicit routing and a java applet SSH (or perhaps telnet) client to 
connect.

Regards
Henrik

Re: [Qemu-devel] Qemu sandbox for teaching

[Tom Sandholm]

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Jerome,

Yes.
Using a fairly large server, (i.e. xeon dual with 4Gb ram & 120GB disk), 
and installing...
1.  Qemu
2.  vde (virtual distributed ethernet)
3.  tun/tap device drivers (usually kernel module).
I've been able to create 8 conncurrent qemu instances with reasonable 
performance.
I recompiled qemu, without sdl, as to get qemu able to run in batch, 
without the need of a console window.
I haven't been able to get qemu to run in batch using any of the 
redirected console options (like pty, or -nographic option).
I created a script that starts the vde (tun/tap), used as a tunnel from 
my home network, to the virtual network that all the qemu instances 
connect to.
Then I run a qemu startup script that starts the qemu instance, with 
assigned disk image, assigned mac address (remember you'll need 
differenct Mac's for each instance), and places it in background.
I then installed Debian "sarge" on a "master qemu instance", and also 
install bootcdwrite tools to "image" the newly installed Unix "base".  
(of course you'll also want to install ssh services).
Then I "imaged" the live system onto a cdrom image.  I can then just 
boot the cdrom image, to start-up a qemu-instance, and use the 
bootcdwrite command to write the cdrom image to virtual hard disk.  Of 
course you could just run the qemu-instance fromthe live-run-cdrom ISO, 
and just nfs mount a home directory for any form of "perm" storage (of 
course you'd NFS mount from the host-os.  You may also use the virtual 
floppy image to hold qemu-instance specifics, such as hostname, 
ipaddress, etc.  See the Debian doc's on bootcdwrite for details.
I expect that you may be able to install apache on the host machine, and 
use java-webstart to invoke some form of ssh-client, that users would 
use to ssh into their assigned qemu-instance engine.

Best of luck
Tom Sandholm


Jerome Warnier wrote:

>Does someone here have an idea on how to do the following using Qemu,
>but I'm open to other suggestions:
>
>I would like to provide a UNIX CLI sandbox for users to poke around in a
>UNIX course. It would be better if available from the web (preferably
>without having to install anything on the users' PC), and Free (as in
>free speach).
>The problem is that I need to give them root access, or at least a
>simulation.
>It would be even better if we could for instance install RedHat in it,
>but it's not really required.
>
>Thanks
>  
>

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Re: [Qemu-devel] Qemu sandbox for teaching

[Lennert Buytenhek]

On Sat, May 28, 2005 at 09:22:23AM -0400, Tom Sandholm wrote:

> Yes.
> Using a fairly large server, (i.e. xeon dual with 4Gb ram & 120GB disk), 
> and installing...

Hmm.. 8 el-cheapo whitebox PCs just might be cheaper than that dual
xeon with 4gb ram and 120G of disk of yours.  ;-)

(They'll likely consume more power, though.)


--L

Re: [Qemu-devel] Qemu sandbox for teaching

[Paul Brook]

On Saturday 28 May 2005 14:31, Lennert Buytenhek wrote:
> On Sat, May 28, 2005 at 09:22:23AM -0400, Tom Sandholm wrote:
> > Yes.
> > Using a fairly large server, (i.e. xeon dual with 4Gb ram & 120GB disk),
> > and installing...
>
> Hmm.. 8 el-cheapo whitebox PCs just might be cheaper than that dual
> xeon with 4gb ram and 120G of disk of yours.  ;-)
>
> (They'll likely consume more power, though.)

Not if you use the via epia mini-itx boards they won't.

Paul