Re: [Vserver] Host and guest compatability

From: Jim Wight <j.k.wight_at_ncl.ac.uk>
Date: Wed 09 Aug 2006 - 16:56:06 BST
Message-Id: <1155138966.17993.152.camel@beadnell.ncl.ac.uk>

On Wed, 2006-08-09 at 09:58 -0500, Michael S. Zick wrote:
> On Wed August 9 2006 09:30, Jim Wight wrote:
> > On Wed, 2006-08-09 at 08:50 -0500, Michael S. Zick wrote:
> > > Since the chroot command does not change the context (or namespace) then
> > > it must be the act of trying to run in a different context that breaks
> > > something.
> > >
> > > My guess, the dynamic library handling.
> > >
> > > Try executing /lib/libc.so.6 in the guest context, see if you get a
> > > normal report out of it. It should print its build information,
> > > including its version.
> >
> > What command is required to accomplish that?
> >
>
> The file libc.so.6 is an executable.
>
> Just substitute "/lib/libc.so.6" for where you are using "/usr/bin/env"
> in your testing.

OK. I changed the value of _ENV in util-vserver-vars, which results in

# vserver fc5 start
GNU C Library development release version 2.3.5, by Roland McGrath et
al.
Copyright (C) 2005 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.0.1 20050727 (Red Hat 4.0.1-5).
Compiled on a Linux 2.4.20 system on 2005-08-15.
Available extensions:
        GNU libio by Per Bothner
        crypt add-on version 2.1 by Michael Glad and others
        Native POSIX Threads Library by Ulrich Drepper et al
        The C stubs add-on version 2.1.2.
        BIND-8.2.3-T5B
        NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
        Glibc-2.0 compatibility add-on by Cristian Gafton
        GNU Libidn by Simon Josefsson
Thread-local storage support included.
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.
vshelper.init: can not determine xid of vserver 'fc5'; returned value
was ''

which is what executing /lib/libc.so.6 on the (FC4) host gives.
Presumably you would expect the output to be the same as

# chroot /vservers/fc5 /lib/libc.so.6
GNU C Library development release version 2.4, by Roland McGrath et al.
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.1.0 20060304 (Red Hat 4.1.0-3).
Compiled on a Linux 2.6.9 system on 2006-05-12.
Available extensions:
        The C stubs add-on version 2.1.2.
        crypt add-on version 2.1 by Michael Glad and others
        GNU Libidn by Simon Josefsson
        GNU libio by Per Bothner
        NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
        Native POSIX Threads Library by Ulrich Drepper et al
        BIND-8.2.3-T5B
Thread-local storage support included.
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.

> Or build your own command out of the low level tools, similar too:
>
> chbind --ip ${VADDRESS} -- vcontext --create --xid ${VID} --chroot -- \
> /usr/bin/env -i HOSTNAME=${VROOT} HOME=/root TERM="${TERM}" PS1='\u:\w\$ ' \
> PATH='/usr/local/sbin:/usr/sbin:/sbin:/usr/local/bin:/usr/bin:/bin' /bin/bash --login +h

Like this

# cd /vservers/fc5
# vcontext --create --xid 49142 --chroot -- /usr/bin/env -i HOME=/root
PATH='/bin:/sbin:/usr/bin:/usr/sbin' /bin/bash --login +h
New security context is 49142
[root@turing /]# cat /etc/redhat-release
Fedora Core release 5 (Bordeaux)
[root@turing /]# /lib/libc.so.6
GNU C Library development release version 2.4, by Roland McGrath et al.
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.1.0 20060304 (Red Hat 4.1.0-3).
Compiled on a Linux 2.6.9 system on 2006-05-12.
Available extensions:
        The C stubs add-on version 2.1.2.
        crypt add-on version 2.1 by Michael Glad and others
        GNU Libidn by Simon Josefsson
        GNU libio by Per Bothner
        NIS(YP)/NIS+ NSS modules 0.19 by Thorsten Kukuk
        Native POSIX Threads Library by Ulrich Drepper et al
        BIND-8.2.3-T5B
Thread-local storage support included.
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.

which is the same as from 'chroot /vservers/fc5 /lib/libc.so.6'

Jim

_______________________________________________
Vserver mailing list
Vserver@list.linux-vserver.org
http://list.linux-vserver.org/mailman/listinfo/vserver
Received on Wed Aug 9 16:56:35 2006

[Next/Previous Months] [Main vserver Project Homepage] [Howto Subscribe/Unsubscribe] [Paul Sladen's vserver stuff]
Generated on Wed 09 Aug 2006 - 16:56:41 BST by hypermail 2.1.8