Non-native architectures

[Misha Shnurapet]

Hello.

Currently, running an x86_64 system I can also re-spin 32-bit versions
by using "setarch i686" in the command line:

su -c "setarch i686 livecd-creator
--config=/usr/share/spin-kickstarts/fedora-livecd-desktop.ks"

But it does not work other way around. For example,

su -c "setarch x86_64 livecd-creator
--config=/usr/share/spin-kickstarts/fedora-livecd-desktop.ks"

gives an error. Same for another architecture. I think there's something
wrong with this. Is it possible to create spins for other architectures?
Can it be fixed?

Thank you.

-- 
Best regards,
Misha Shnurapet, Fedora Project Contributor
http://fedoraproject.org/wiki/User:Shnurapet
shnurapet at fedoraproject.org, GPG: 00217306

[Bruno Wolff III]

On Sun, May 30, 2010 at 00:49:28 +0900,
  Misha Shnurapet <zayzayats(a)yandex.ru&gt; wrote:
>  Hello.
>  
>  Currently, running an x86_64 system I can also re-spin 32-bit versions
>  by using "setarch i686" in the command line:
>  
>  su -c "setarch i686 livecd-creator
>  --config=/usr/share/spin-kickstarts/fedora-livecd-desktop.ks"
>  
>  But it does not work other way around. For example,
>  
>  su -c "setarch x86_64 livecd-creator
>  --config=/usr/share/spin-kickstarts/fedora-livecd-desktop.ks"
>  
>  gives an error. Same for another architecture. I think there's something
>  wrong with this. Is it possible to create spins for other architectures?
>  Can it be fixed? 
Normally you need to use mock to do this. i686 on x86_64 probably works
because i686 code will run on an x86_64 machine.

[Mads Kiilerich]

Bruno Wolff III wrote, On 05/29/2010 06:16 PM:
>  On Sun, May 30, 2010 at 00:49:28 +0900,
>     Misha Shnurapet<zayzayats(a)yandex.ru>  wrote:
>     
> > Hello.
> >
> > Currently, running an x86_64 system I can also re-spin 32-bit versions
> > by using "setarch i686" in the command line:
> >
> > su -c "setarch i686 livecd-creator
> > --config=/usr/share/spin-kickstarts/fedora-livecd-desktop.ks"
> >
> > But it does not work other way around. For example,
> >
> > su -c "setarch x86_64 livecd-creator
> > --config=/usr/share/spin-kickstarts/fedora-livecd-desktop.ks"
> >
> > gives an error. Same for another architecture. I think there's something
> > wrong with this. Is it possible to create spins for other architectures?
> > Can it be fixed?
> >      
>  Normally you need to use mock to do this. i686 on x86_64 probably works
>  because i686 code will run on an x86_64 machine.
>      
Really?

My answer would be that the pre and post scripts of the rpm packages 
executes binaries inside the chroot during installations, so CDs has to 
be created on a binary compatible platform. i686 on x64_64 is thus a 
special case.

/Mads

[Bruno Wolff III]

On Sat, May 29, 2010 at 21:20:38 +0200,
  Mads Kiilerich <mads(a)kiilerich.com&gt; wrote:
>  Bruno Wolff III wrote, On 05/29/2010 06:16 PM:
>  > Normally you need to use mock to do this. i686 on x86_64 probably works
>  > because i686 code will run on an x86_64 machine.
>  >    
>  
>  Really? 
I could be wrong.

>  My answer would be that the pre and post scripts of the rpm packages
>
>  executes binaries inside the chroot during installations, so CDs has to 
>  be created on a binary compatible platform. i686 on x64_64 is thus a 
>  special case. 
I know mock has been recommended to me for other reasons, but I have not
personally tried to do cross arch live image builds.

[Jasper Hartline]

You are correct. Anaconda and Yum RPM post scripts operate in the fake
root environment.
%post section of kickstart file can be chrooted or not.. depending on
what you set.
I have built many LiveCDs for x86_64 before from an i386/i686 machine.
It comes down to some simple things, Anaconda/Yum will expand the variables
$basearch and $releasever depending on what the environment is set as,
if you're using a kickstart
file with repos using $basearch and $releasever, it will build a CD
for the architecture you are on.

To build for another platform just change those variables to be hard
coded values.
The only other way to have livecd-creator make a CD for a specific target is to
have it use a --target or --platform flags which can be passed on teh
command line.
Of course this functionality doesn't exist, nor do I know if it would
be preferrable to just
pulling things from teh kickstart file, which I doubt.


On Sat, May 29, 2010 at 12:20 PM, Mads Kiilerich <mads(a)kiilerich.com&gt; wrote:
>  Bruno Wolff III wrote, On 05/29/2010 06:16 PM:
> > On Sun, May 30, 2010 at 00:49:28 +0900,
> >    Misha Shnurapet&lt;zayzayats(a)yandex.ru&gt;  wrote:
> >
> >> Hello.
> >>
> >> Currently, running an x86_64 system I can also re-spin 32-bit versions
> >> by using "setarch i686" in the command line:
> >>
> >> su -c "setarch i686 livecd-creator
> >> --config=/usr/share/spin-kickstarts/fedora-livecd-desktop.ks"
> >>
> >> But it does not work other way around. For example,
> >>
> >> su -c "setarch x86_64 livecd-creator
> >> --config=/usr/share/spin-kickstarts/fedora-livecd-desktop.ks"
> >>
> >> gives an error. Same for another architecture. I think there's something
> >> wrong with this. Is it possible to create spins for other architectures?
> >> Can it be fixed?
> >>
> > Normally you need to use mock to do this. i686 on x86_64 probably works
> > because i686 code will run on an x86_64 machine.
> >
>
>  Really?
>
>  My answer would be that the pre and post scripts of the rpm packages
>  executes binaries inside the chroot during installations, so CDs has to
>  be created on a binary compatible platform. i686 on x64_64 is thus a
>  special case.
>
>  /Mads
>  --
>  livecd mailing list
>  livecd(a)lists.fedoraproject.org
>  https://admin.fedoraproject.org/mailman/listinfo/livecd
>

[Misha Shnurapet]

В Сбт, 29/05/2010 в 20:38 -0700, Jasper Hartline пишет: 
>  I have built many LiveCDs for x86_64 before from an i386/i686
> machine.
>  It comes down to some simple things, Anaconda/Yum will expand the variables
>  $basearch and $releasever depending on what the environment is set as,
>  if you're using a kickstart
>  file with repos using $basearch and $releasever, it will build a CD
>  for the architecture you are on.
>  
>  To build for another platform just change those variables to be hard
>  coded values. 
This is very interesting. If changing those values to hardcoded ones
works as desired, maybe there is also a way to 'patch' them right away
in the command line executing the livecd-creator (like I tried to do
with 'setarch')?

-- 
Best regards,
Misha Shnurapet, Fedora Project Contributor
http://fedoraproject.org/wiki/User:Shnurapet
shnurapet at fedoraproject.org, GPG: 00217306

[Jasper Hartline]

Yeah. It would be simply before doing string replacement on the values
to whatever you set.
This wouldn't be desirable though for anyone but yourself, since of
course we don't want to modigy
the file directly, we simply need to set yumvars['basearch'] and
yumvars['releasever']
which happens later.

yumvars = _getEnvVar()
sets up yumvars.

On Sat, May 29, 2010 at 11:21 PM, Misha Shnurapet <zayzayats(a)yandex.ru&gt; wrote:

>  This is very interesting. If changing those values to hardcoded ones
>  works as desired, maybe there is also a way to 'patch' them right away
>  in the command line executing the livecd-creator (like I tried to do
>  with 'setarch')?