====== Setup a CentOS schroot on Debian ======

Inspired by the setup of Debian chroot for sbuild:
  * http://wiki.debian.org/sbuild?rev=19
  * http://wiki.debian.org/mk-sbuild

<code bash>
$ apt-get install schroot sbuild btrfs-tools
</code>

We will use the btrfs flavor of schroot.

Since btrfs is still experimental, I choose to create loopback device formated with btrfs and mounted as follows:

<code bash>
$ cat <EOF >> /etc/fstab
/home/schroot-btrfs     /srv/chroot     btrfs   defaults        0       0
EOF

/home/schroot-btrfs is a 20G file (to created if, please help yourself)
</code>

Create the centos6 schroot configuration file:

<code bash>
$ cat < 'EOF' > /etc/schroot/chroot.d/centos6-amd64
[centos6-amd64]
type=btrfs-snapshot
description=CentOS 6/amd64 autobuilder
groups=root,sbuild
root-groups=root,sbuild
profile=sbuildrpm
btrfs-source-subvolume=/srv/chroot/centos6-amd64
btrfs-snapshot-directory=/srv/chroot/snapshots
EOF
</code>

Setup the filesystem subvolume and snapshots

<code bash>
$ btrfs subvolume create /srv/chroot/centos6-amd64

$ mkdir -p /srv/chroot/snapshots
</code>

Bootstrap the centos system:

<code bash>
$ cat EOF >> /etc/rinse/rinse.conf
[centos-6]
mirror       = http://ftp.ciril.fr/pub/linux/centos/6/os/i386/Packages/
mirror.amd64 = http://ftp.ciril.fr/pub/linux/centos/6/os/x86_64/Packages/
EOF

$ rinse --distribution centos-6 --arch amd64 --directory /srv/chroot/centos6-amd64/ 
</code>

We copy the /dev from a Debian schroot (rinse's one one is buggy)
<code bash>
$ cp -a /srv/chroot/sid-amd64-sbuild/dev /srv/chroot/centos6-amd64/
</code>

Finally, we do some customizations to make the centos system schroot friendly

<code bash>
$ echo centos6-amd64 > /srv/chroot/centos6-amd64/etc/debian_chroot
$ cat << 'EOF' > /srv/chroot/centos6-amd64/etc/profile.d/debian_chroot.sh
# set variable identifying the chroot you work in (used in the prompt below)
if [ -z "${debian_chroot:-}" ] && [ -r /etc/debian_chroot ]; then
    debian_chroot=$(cat /etc/debian_chroot)
fi

# set a fancy prompt (non-color, overwrite the one in /etc/profile)
PS1='${debian_chroot:+($debian_chroot)}\u@\h:\w\$ '

EOF
</code>


Test
<code bash>
$ sudo adduser <user> sbuild
</code>
(logout and login again)

Enter the snapshoted chroot:
<code bash>
$ schroot -c chroot:centos6-amd64 ...
</code>

Enter the source chroot (to upgrade the base system for instance)
<code bash>
$ sudo schroot -c source:centos6-amd64 ..
</code>

You can then use sbuildrpm or any other test in the CentOS schroot environement...