Failed to create sbuild chroot for cross-compiling

[Holger Wansing <hwansing@mailbox.org>]

Hi all,

I need to get some debian-installer packages uploaded for s390x and mips.

Since I have no hardware for that archs, I suspect the way to go is to create
a chroot for that archs, right?
My hardware is amd64.

I have a working sbuild chroot for amd64, for creation of that I followed
https://wiki.debian.org/sbuild

Based on this, I tried to create chroots for s390x and mips, too. 
But that fails.

Is there some documentation for this use case?
The manpage of sbuild-createchroot contains commandline examples for several
use cases, but not for cross-compiling.


I used:

sbuild-createchroot --arch=s390x --foreign --include=eatmydata,ccache,gnupg unstable /srv/chroot/unstable-s390x-sbuild http://deb.debian.org/debian

and the output ends with:

----snip-----
I: Please add any additional APT sources to /srv/chroot/unstable-s390x-sbuild/etc/apt/sources.list
I: schroot chroot configuration written to /etc/schroot/chroot.d/unstable-s390x-sbuild-awxveq.
   +------------------------------------------------------------------------
   |[unstable-s390x-sbuild]
   |description=Debian unstable/s390x autobuilder
   |groups=root,sbuild
   |root-groups=root,sbuild
   |profile=sbuild
   |type=directory
   |directory=/srv/chroot/unstable-s390x-sbuild
   |union-type=overlay
   +------------------------------------------------------------------------
I: Please rename and modify this file as required.
W: The selected architecture and the current architecture do not match
W: (s390x versus amd64).
I: You probably need to add a personality option (see schroot(1)).
I: You may want to report your use case to the sbuild developers so that
I: the appropriate option gets automatically added in the future.

I: sudo chroot configuration linked as /etc/sbuild/chroot/unstable-s390x-sbuild.
/usr/sbin/chroot: der Befehl „/bin/sh“ konnte nicht ausgeführt werden: No such file or directory
/usr/sbin/chroot: der Befehl „/bin/sh“ konnte nicht ausgeführt werden: No such file or directory
E: Failed to create build directory /build
Failed to set up chroot
E: Error creating chroot session: skipping apt update
I: Successfully set up unstable chroot.
I: Run "sbuild-adduser" to add new sbuild users.
----snap------


After that, I execute

/srv/chroot/unstable-s390x-sbuild/debootstrap/debootstrap unstable /srv/chroot/unstable-s390x-sbuild/

as documented for sbuild-createchroot's --foreign option. And that finishs without error.


However, sbuild cannot create a chroot session, the sbuild command
sbuild --build=s390x --host=amd64 -s -d unstable --source-only-changes --run-lintian
fails with

----snip----
Package: s390-dasd
Version: 0.0.60
Source Version: 0.0.60
Distribution: unstable
Machine Architecture: amd64
Host Architecture: amd64
Build Architecture: s390x
Build Type: source,any

E: Failed to execute “/usr/bin/getent”: No such file or directory
sh: 1: cannot create /var/run/schroot/mount/unstable-s390x-sbuild-66ca4af6-72c6-4bec-9c69-ae9dd9d3bab0/etc/group: Permission denied
E: Failed to create group sbuild
Failed to set up chroot
E: Error creating chroot session: skipping s390-dasd

+------------------------------------------------------------------------------+
| Summary                                                                      |
+------------------------------------------------------------------------------+

Build Architecture: s390x
Build Type: source,any
Build-Space: 0
Build-Time: 0
Distribution: unstable
Fail-Stage: create-session
Host Architecture: amd64
Install-Time: 0
Job: /home/holgerw/uploading-d-i/d-i/packages/s390-dasd_0.0.60.dsc
Machine Architecture: amd64
Package: s390-dasd
Package-Time: 0
Source-Version: 0.0.60
Space: 0
Status: failed
Version: 0.0.60
--------------------------------------------------------------------------------
Finished at 2018-08-25T18:24:29Z
Build needed 00:00:00, 0k disk space
E: Error creating chroot session: skipping s390-dasd
-----snap-----


I fail to see what's wrong.
"Permission denied" points on some lacking permissions. I have added the user
to the sbuild group, as documented on
https://wiki.debian.org/sbuild
And: the sbuild chroot for amd64 works fine for the same user.


Could somebody help me?
Thanks

Holger



-- 
Holger Wansing <hwansing@mailbox.org>
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