[9fans] rc dying in my drawterm on xen

[9fans] rc dying in my drawterm on xen

[Ronald G. Minnich]

this is actually kind of interesting. The rc is dying very reliably when I 
run ps. Now, watching the system calls (I log them all to a debug stream) 
I see a child of rc opening up rc's notepg and writing to it ... rc goes
away, does not pass go, life is bad, Ogg is confused. 

Re: [9fans] rc dying in my drawterm on xen

[geoff]

This is probably unrelated, but I had infrequent and mysterious rc
breakage until I recompiled rc from source.  The new binary was not
quite the same size as the old one and hasn't broken yet.

Re: [9fans] rc dying in my drawterm on xen

[Kenji Okamoto]

Ron, please forgive me to make a silly question.
Does Xen enable to use a machine as both for Linux box and Plan 9
CPU server?   

I mean I'm running a machine usually for Linux box, then, Xen can enable
the machine also for Plan 9 CPU server without rebooting (I don't say terminal, 
because it looks not so worthy at least to me...

Sorry, I don't understand yet what is Xen.

Kenji

Re: [9fans] rc dying in my drawterm on xen

[David Leimbach]

> Sorry, I don't understand yet what is Xen.
> 
Xen is a "virtual machine monitor".  It allows you  to host other
operating systems, kind of similar to the way you might run many
instances of VMWare on a linux/windows box but with a more
"performant" implementation.  Xen doesn't try to emulate too much
hardware and it actually multiplexes  the hardware you have.

As such, you can run many different "domains" with Linux, NetBSD or
Plan 9 [once Ron irons out the last few bugs...:)].

I had a Xen installation up until a few minutes ago when I hosed my
machine doing something else :).  Basically you use GRUB to boot Xen
and then a special "Xen-linux" as a controlling "domain 0".  From
there you can start a xen daemon which lets you create new domains
with configuration files to assign disk partitions or files as
filesystems for other kernels.

It's fairly cool stuff.  http://xen.sf.net has some information I
believe.  It's also really easy to build Xen2 from source.  The
makefile even downloads the kernel and patches it for you IIRC so
getting started is pretty easy.

I'm buying extra disks just to play with it from my local mom'n'pop
computer store up the street [support the little guy!!!].

Dave

> Kenji
> 
>

Re: [9fans] rc dying in my drawterm on xen

[Ronald G. Minnich]

On Thu, 18 Nov 2004, Kenji Okamoto wrote:
> Does Xen enable to use a machine as both for Linux box and Plan 9
> CPU server?   

yes, that's what I'm doing now. 

> I mean I'm running a machine usually for Linux box, then, Xen can enable
> the machine also for Plan 9 CPU server without rebooting (I don't say terminal, 
> because it looks not so worthy at least to me...

my plan is to have it as easy for me to fire up plan 9 on a linux box as 
it is to run 'cat'.

ron

Re: [9fans] rc dying in my drawterm on xen

[C H Forsyth]

>>my plan is to have it as easy for me to fire up plan 9 on a linux box as 
>>it is to run 'cat'.

given my experience of the time it takes to get an xterm going under kde on a reasonably-powered
Thinkpad, you should have plenty of slack.

Re: [9fans] rc dying in my drawterm on xen

[Kenji Okamoto]

> my plan is to have it as easy for me to fire up plan 9 on a linux box as 
> it is to run 'cat'.

If RPC call such as ftp protocol from outside to the machine, which OS
replies it?    Is there any mechanism to make the priority for them?
If so, it it easy?   I'm now considering a situation httpd daemon is running
on Linux box, and would like to use it for http call, although httpd of
Plan 9 is also running.

Kenji

Re: [9fans] rc dying in my drawterm on xen

[Lucio De Re]

> If RPC call such as ftp protocol from outside to the machine, which OS
> replies it?    Is there any mechanism to make the priority for them?
> If so, it it easy?   I'm now considering a situation httpd daemon is running
> on Linux box, and would like to use it for http call, although httpd of
> Plan 9 is also running.

I presume the two operating systems use different IP addresses, the
way VMware does it.

++L

Re: [9fans] rc dying in my drawterm on xen

[Ronald G. Minnich]

On Fri, 19 Nov 2004, Lucio De Re wrote:

> I presume the two operating systems use different IP addresses, the
> way VMware does it.

and even different macs ...

ron

Re: [9fans] rc dying in my drawterm on xen

[Wes Kussmaul]

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Re: [9fans] rc dying in my drawterm on xen

[Russ Cox]

> How can it do that? I thought the mac address came from the NIC hardware.

it can lie.

russ

Re: [9fans] rc dying in my drawterm on xen

[David Leimbach]

I just realized that Ron's plan 9 port was for the older version of
Xen... I've got Xen 2.0.1 running and I'd be glad to help test it out
if Ron needs any help.

I compiled the whole thing myself on Debian... not terribly difficult
as the makefile downloads and patches/configures/builds the "Xenified
Host Linux" that I can launch other Linux's from now.

I also built the NetBSD2.0-xen guest but have no filesystem for it to mount :).

Let me know if I can be of assistance.

Dave


On Fri, 19 Nov 2004 12:26:55 -0500, Russ Cox <russcox@gmail.com> wrote:
> > How can it do that? I thought the mac address came from the NIC hardware.
> 
> it can lie.
> 
> russ
>

Re: [9fans] rc dying in my drawterm on xen

[Ronald G. Minnich]

On Fri, 19 Nov 2004, David Leimbach wrote:

> I just realized that Ron's plan 9 port was for the older version of
> Xen... I've got Xen 2.0.1 running and I'd be glad to help test it out
> if Ron needs any help.

yeah, I will be doing release paperwork monday. 


Here's what is happening when drawterm fails:
rc is started up
rc runs ps
ps gets all the data out of /proc/*/status
ps does a Pwrite of about 3K bytes. 

now it gets weird, but at least part of what is going on is that 
cpu does a read from it's opened fd for /mnt/term/dev/cpunote, and gets -1 
back. That's a hangup from the server (srvold9p I guess, right?) and so it 
sends a hangup to the group, everyone exits. 

Now what is going on between that Pwrite from ps and the hangup is still 
not real clear to me, but at least i've narrowed it down to that. 

Note that cpu -h localhost works fine with no problems. There is some 
difference (srvold9p) that is causing trouble here. 

Also, my Plan 9 port is to the unstable port of Xen, but it is pretty 
recent, and the Xen guys tell me that the interface to guest OSes has not 
changed terribly, so this may not be too bad. 

But having more eyes on my code will sure be useful.

ron

Re: [9fans] rc dying in my drawterm on xen

[David Leimbach]

On Fri, 19 Nov 2004 11:04:16 -0700 (MST), Ronald G. Minnich
<rminnich@lanl.gov> wrote:
> 
> 
> On Fri, 19 Nov 2004, David Leimbach wrote:
> 
> > I just realized that Ron's plan 9 port was for the older version of
> > Xen... I've got Xen 2.0.1 running and I'd be glad to help test it out
> > if Ron needs any help.
> 
> yeah, I will be doing release paperwork monday.

Will it be out before Thanksgiving? :)  I've got a nice long weekend
for this sort of stuff.

I understand you probably have to clear it all.

- Dave

Re: [9fans] rc dying in my drawterm on xen

[Ronald G. Minnich]

On Fri, 19 Nov 2004, David Leimbach wrote:

> I understand you probably have to clear it all.

I am hoping that's fast.

ron

Re: [9fans] rc dying in my drawterm on xen

[Ronald G. Minnich]

On Fri, 19 Nov 2004, Wes Kussmaul wrote:
>>  and even different macs ...
> 
> How can it do that? I thought the mac address came from the NIC hardware.
> 


remember that in the VM world ethernet interfaces are virtual, so you can 
give it any mac you want.

ron

Re: [9fans] rc dying in my drawterm on xen

[Ronald G. Minnich]

On Fri, 19 Nov 2004, Kenji Okamoto wrote:

> > my plan is to have it as easy for me to fire up plan 9 on a linux box as 
> > it is to run 'cat'.
> 
> If RPC call such as ftp protocol from outside to the machine, which OS
> replies it?    

The Xen domains are bridged to the ethernet via the linux br device. So 
the routing of packets to domains is by MAC address.

ron

Re: [9fans] rc dying in my drawterm on xen

[Kenji Okamoto]

> The Xen domains are bridged to the ethernet via the linux br device. So 
> the routing of packets to domains is by MAC address.

Hmm, it's cool.

Kenji  --once annoyed by T42's bridge device though...