CentOS - Dec 2012 - Building a C5 chroot on a C6 machine

I'm trying to do something slightly silly; rather than having a C5 machine
and a C6 machine around for compiling and testing, I want to create a C5
chroot area.  Something similar to "mock" but using lvm snapshots and
some
local config specific stuff.

(Potentially even using Linux Containers to enter the chroot environment).

So I thought I'd build out the chroot...

  % cat /etc/yum.repos.d/c5.repo
  [c5]
  name=CentOS-$releasever - Media
  baseurl=http://repo/CentOS/DVD/CentOS-5-x86_64/
  gpgcheck=0
  gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
  enabled=0


  [c5-update]
  name=CentOS-$releasever - Updates local
  baseurl=http://repo/CentOS/updates/centos5/x86_64/
  gpgcheck=0
  gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
  enabled=0


Now I can do
  yum --disablerepo=* --enablerepo=c5* -y --installroot=$ROOT install $rpms

(where $rpms is derived from what anaconda left behind on an old install)

So far so... "ok".  Some issues with post-install scripts breaking,
but
it mostly works.

  Verifying  : 3:traceroute-2.0.1-6.el5.x86_64                          235/237
  Verifying  : setup-2.5.58-9.el5.noarch                                236/237
  Verifying  : at-3.1.8-84.el5.x86_64                                   237/237

Installed:
  MAKEDEV.x86_64 0:3.23-1.2
  SysVinit.x86_64 0:2.86-17.el5
  acl.x86_64 0:2.2.39-8.el5
[etc etc]

EXCEPT...

  test2.pts/0% chroot /mnt5 /bin/sh
  sh-3.2# ls
  bin   dev  home  lib64       media  opt   root  selinux  sys  usr
  boot  etc  lib   lost+found  mnt    proc  sbin  srv      tmp  var
  sh-3.2# rpm -qa
  rpmdb: /var/lib/rpm/Packages: unsupported hash version: 9
  error: cannot open Packages index using db3 - Invalid argument (22)
  error: cannot open Packages database in /var/lib/rpm

The rpm database is in the format of C6, so the C5 programs can't
read it!

Anyone have any ideas on how I can work around this problem?  It's
a little annoying!

Thanks,

-- 

rgds
Stephen

On Fri, Dec 14, 2012 at 12:32 PM, Stephen Harris <lists at spuddy.org>
wrote:
> I'm trying to do something slightly silly; rather than having a C5
machine
> and a C6 machine around for compiling and testing, I want to create a C5
> chroot area.  Something similar to "mock" but using lvm snapshots
and some
> local config specific stuff.
>
> (Potentially even using Linux Containers to enter the chroot environment).
Even if it is possible to get everything right that way, is it really
worth the trouble compared to a VM?

-- 
   Les Mikesell
    lesmikesell at gmail.com

Stephen Harris wrote:
> I'm trying to do something slightly silly; rather than having a C5
machine
> and a C6 machine around for compiling and testing, I want to create a C5
> chroot area.  Something similar to "mock" but using lvm snapshots
and some
> local config specific stuff.
>
> (Potentially even using Linux Containers to enter the chroot environment).
>
> So I thought I'd build out the chroot...
>
>    % cat /etc/yum.repos.d/c5.repo
>    [c5]
>    name=CentOS-$releasever - Media
>    baseurl=http://repo/CentOS/DVD/CentOS-5-x86_64/
>    gpgcheck=0
>    gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
>    enabled=0
>
>
>    [c5-update]
>    name=CentOS-$releasever - Updates local
>    baseurl=http://repo/CentOS/updates/centos5/x86_64/
>    gpgcheck=0
>    gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-5
>    enabled=0
>
>
> Now I can do
>    yum --disablerepo=* --enablerepo=c5* -y --installroot=$ROOT install
$rpms
>
> (where $rpms is derived from what anaconda left behind on an old install)
>
> So far so... "ok".  Some issues with post-install scripts
breaking, but
> it mostly works.
>
>    Verifying  : 3:traceroute-2.0.1-6.el5.x86_64                         
235/237
>    Verifying  : setup-2.5.58-9.el5.noarch                               
236/237
>    Verifying  : at-3.1.8-84.el5.x86_64                                  
237/237
>
> Installed:
>    MAKEDEV.x86_64 0:3.23-1.2
>    SysVinit.x86_64 0:2.86-17.el5
>    acl.x86_64 0:2.2.39-8.el5
> [etc etc]
>
> EXCEPT...
>
>    test2.pts/0% chroot /mnt5 /bin/sh
>    sh-3.2# ls
>    bin   dev  home  lib64       media  opt   root  selinux  sys  usr
>    boot  etc  lib   lost+found  mnt    proc  sbin  srv      tmp  var
>    sh-3.2# rpm -qa
>    rpmdb: /var/lib/rpm/Packages: unsupported hash version: 9
>    error: cannot open Packages index using db3 - Invalid argument (22)
>    error: cannot open Packages database in /var/lib/rpm
>
> The rpm database is in the format of C6, so the C5 programs can't
> read it!
>
> Anyone have any ideas on how I can work around this problem?  It's
> a little annoying!
perhaps if you kept the rpms that were installed by yum, you could
rpm -i --justdb *.rpm
within your chroot.

If necessary first remove the rpm database and rpm --initdb or some such.

not sure, but it might work

On 12/14/2012 10:32 AM, Stephen Harris wrote:
> Something similar to "mock" but using lvm snapshots and some
> local config specific stuff.
If you're not using mock, you'll have to re-engineer basically 
everything that it does.  My advice would be to try to get mock to work 
for you.  It'll be less work than trying to re-engineer mock and then 
get that result to work for your needs.