Re: [Xen-users] Trying to create new domain on 4.3 but domU is starting crashed (-sc-)

[Ian Murray <murrayie@xxxxxxxxxxx>]

----- Original Message -----
> From: Ian Campbell <ian.campbell@xxxxxxxxxx>
> To: Ian Murray <murrayie@xxxxxxxxxxx>
> Cc: "xen-users@xxxxxxxxxxxxxxxxxxx" <xen-users@xxxxxxxxxxxxxxxxxxx>
> Sent: Friday, 26 July 2013, 13:44
> Subject: Re: [Xen-users] Trying to create new domain on 4.3 but domU is 
> starting crashed (-sc-)
> 
> On Thu, 2013-07-25 at 10:41 +0100, Ian Murray wrote:
>> 
>> 
>> 
>>  ----- Original Message -----
>>  > From: Ian Campbell <ian.campbell@xxxxxxxxxx>
>>  > To: Ian Murray <murrayie@xxxxxxxxxxx>
>>  > Cc: "xen-users@xxxxxxxxxxxxxxxxxxx" 
> <xen-users@xxxxxxxxxxxxxxxxxxx>
>>  > Sent: Thursday, 25 July 2013, 4:37
>>  > Subject: Re: [Xen-users] Trying to create new domain on 4.3 but domU 
> is starting crashed (-sc-)
>>  > 
>>  > On Wed, 2013-07-24 at 20:07 +0100, Ian Murray wrote:
>>  >> 
>>  >> 
>>  >> 
>>  >>  ----- Original Message -----
>>  >>  > From: Ian Campbell <ian.campbell@xxxxxxxxxx>
>>  >>  > To: Ian Murray <murrayie@xxxxxxxxxxx>
>>  >>  > Cc: "xen-users@xxxxxxxxxxxxxxxxxxx" 
>>  > <xen-users@xxxxxxxxxxxxxxxxxxx>
>>  >>  > Sent: Wednesday, 24 July 2013, 19:36
>>  >>  > Subject: Re: [Xen-users] Trying to create new domain on 4.3 
> but domU 
>>  > is starting crashed (-sc-)
>>  >>  > 
>>  >>  > On Wed, 2013-07-24 at 19:22 +0100, Ian Murray wrote:
>>  >>  >>  Any suggestions would be greatly received. 
>>  >>  > 
>>  >>  > Do you get anything out of the guest console? I think if you 
> set
>>  >>  >     on_crash = "preserve"
>>  >>  > you can still use "xl console" after the crash or 
> else you 
>>  > can 
>>  >>  > configure
>>  >>  > xenconsoled to log as per:
>>  >>  > 
> http://wiki.xen.org/wiki/Reporting_Bugs_against_Xen#Guest_console_logs
>>  >> 
>>  >>  Thanks for the reply, Ian.
>>  >> 
>>  >>  I tried both of these and got nothing. xl console <nn> just 
> hangs
>>  >>  until the  ctrl-] out of it and I get no file produced with the
>>  >>  xenconsoled log (didn't get anything for a working domain, 
> either, so
>>  >>  I need to re-check I did that right).
>>  > 
>>  > Not getting anything from a working domain sounds wrong, there should
>>  > definitely be something. You'll need to either "service 
> xencommons
>>  > restart" after editing the sysconfig file or a reboot, in any 
> case it
>>  > should be apparent in the "ps" output for the xenconsoled 
> command that
>>  > the argument has taken affect (it should have --mumble=guest where
>>  > mumble is "trace" or "log" or something like 
> that).
>> 
>>  root      1526  0.0  0.1  90956  1096 ?        SLl  Jul24   0:00 
> /usr/sbin/xenconsoled --pid-file=/var/run/xenconsoled.pid --log=guest
>> 
>>  I must admit, I never have it straight in my head about hvc0 vs xvc0, etc. 
> earlyprintk=xen doesn't seem to have made any difference.
>> 
>>  I am wondering if I did something wrong at compile time (it has been known)
> 
> If with a known good domain you don't get anything
> under /var/log/xen/consoles/ then I don't know what is going on.
> 
> With any modern kernel console=hvc0 is what you want, if your kernel is
> old but not a complete relic then "console=hvc0 xencons=hvc" should
> work.

Anything new is PVOPS Ubuntu kernel 3.2 onwards and I have some CentOS 5 DomU's 
using the original Xen kernel that comes with it.

Thanks for the tip.

> 
>>  > 
>>  > Once you are sure of that then you ought to get *something* out of the
>>  > crashing guest console -- if not then you might try adding
>>  > "earlyprintk=xen" to the guest kernel command line.
>>  > 
>>  >>  I can't help feeling there is a longstanding problem with 
> 12.04 Ubuntu
>>  >>  Xen install files. I tried 64 bit and 32 bits version, same 
> behaviour.
>>  > 
>>  > If you think it might be an Ubuntu bug then trawling Launchpad might 
> be
>>  > worthwhile. Nothing springs to my mind but that doesn't really 
> mean
>>  > much.
>>  > 
>>  >>   I re-read the other thread and the other guy had exactly the 
> same
>>  >>  problem but resolved it by using some Ubuntu Xen creation tool. 
> He was
>>  >>  using Xen 4.2.1
>>  > 
>>  > Depending on what "some Ubuntu Xen creation tool" is it may 
> well be
>>  > using some different kernel or something.
>> 
>>  He succesfully created it using
>> 
>> 
>>  xen-create-image --hostname=ubuntu \
>>    --memory=512mb \
>>    --vcpus=2 \
>>    --lvm=center \
>>    --dhcp \
>>    --pygrub \
>>    --dist=precise
>> 
>>  I've never used this tool and I prefer to do things distribution 
> agnostically as I have Xen on Ubuntu and Scientific Linux 6.4
> 
> Right. The approach above is bascially debbootstrap + using the dom0
> kernel (which you can be reasonably sure is correct).
> 
> One experiment you could try is to extract the kernel from your guest
> image and try booting it via the "dom0 path" method.

The set-up Ubuntu Xen install is encapsulated within a kernel and a ram drive 
image, so there is no extracting to be done (assuming I understand you 
correctly). Having said that, your suggestion did give me an idea to try the 
13.04 kernel with the 12.04 ram drive. It was a fair guess that the kernel 
should be functionally similar and the meat and potatoes of the installer were 
in the ram drive image. As luck would have it, this seems to work a treat and I 
managed to set-up a working 12.04 domU this way, which was the aim.

So, mystery not solved, but at least I have a work-around. I'll re-test this 
against Xen 4.3, just for completeness.

Thanks again for your help.


> 
> 
> Ian.
> 
> 
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> 

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