GitSetup

Git setup on span

The goal is to have a a shared, writeable repository for files controlling the setup of virtual machines, in particular site-info.def and friends, and firstboot scripts.

The git version control software has very good branch management and is fully distributed in setup. All actions are committed to a local repository, and can be pushed to (or pulled from) other repositories.

Gitosis

To have a shared writable repository nonetheless, gitosis is installed on span.nikhef.nl

Instructions for setting up gitosis are found on-line and these were followed almost literally.

git clone git://eagain.net/gitosis.git
cd gitosis/
sudo python setup.py install
sudo adduser -r -d /srv/git -c 'git version control' --shell /bin/sh git
sudo -u git gitosis-init < id-rsa.pub

The management of gitosis is through git!

git clone git@span:gitosis-admin.git
<manage the config file and keydir>
git commit
git push

Now it becomes interesting. After configuring write access to the 'siteinfo' repository, the local siteinfo repository was configured to push to git@span as well:

cd ~/src/siteinfo
git remote add shared git@span.nikhef.nl:siteinfo.git
git push shared

Git-daemon

It is convenient to have read-only anonymous access to selected repositories as well. First, through git-daemon. This comes with the git distribution so the following init script was installed as /etc/init.d/git-daemon.

#!/bin/sh
#
# Startup/shutdown script for Git Daemon
#
#   Linux chkconfig stuff:
#
#   chkconfig: 345 56 10
#   description: Startup/shutdown script for Git Daemon
#
. /etc/init.d/functions

DAEMON=git-daemon
ARGS='--base-path=/srv/git/repositories --detach --user=git --group=git'

prog=git-daemon

start () {
    echo -n $"Starting $prog: "

    # start daemon
    daemon $DAEMON $ARGS
        RETVAL=$?
    echo
    [ $RETVAL = 0 ] && touch /var/lock/git-daemon
    return $RETVAL
}

stop () {
    # stop daemon
    echo -n $"Stopping $prog: "
    killproc $DAEMON
    RETVAL=$?
    echo
    [ $RETVAL = 0 ] && rm -f /var/lock/git-daemon
}

restart() {
    stop
    start
}

case $1 in
    start)
        start
    ;;
    stop)
        stop
    ;;
    restart)
        restart
    ;;
    status)
        status $DAEMON
        RETVAL=$?
    ;;
    *)

    echo $"Usage: $prog {start|stop|restart|status}"
    exit 3
esac

exit $RETVAL

The git-daemon will only export repositories that have the file named

git-daemon-export-ok

in the root, and gitosis-admin is thereby excluded from public view. This file is not under version control.

Gitweb

instructions were found on Gitweb wiki.

The git installation on span is from DAG:

git-1.5.2.1-1.el5.rf

The web application gitweb.cgi is not included in the rpm, so it was built from the sources in the source rpm. The variable GITWEB_EXPORT_OK indicates the file name that flags public visibility for repositories, just like git-daemon.

wget http://dag.wieers.com/rpm/packages/git/git-1.5.2.1-1.rf.src.rpm
rpm -i git-1.5.2.1-1.rf.src.rpm 
cd rpmbuild/SOURCES/
tar xfj git-1.5.2.1.tar.bz2 
cd git-1.5.2.1
make GITWEB_PROJECTROOT=/srv/git/repositories GITWEB_EXPORT_OK=git-daemon-export-ok prefix=/usr gitweb/gitweb.cgi
sudo cp gitweb/gitweb.* /srv/git/gitweb/

The apache configuration in /etc/httpd/conf.d/git.conf:

Alias /git /srv/git/gitweb

<Directory /srv/git/gitweb >
       Options Indexes FollowSymLinks ExecCGI 
	AddHandler cgi-script cgi
       AllowOverride None
	DirectoryIndex gitweb.cgi
	RewriteEngine On
	RewriteBase /git
	RewriteCond %{REQUEST_FILENAME} !-f
	RewriteCond %{REQUEST_FILENAME} !-d
	RewriteRule ^.* /gitweb.cgi/$0 [L,PT]
</Directory>

The repositories can be browsed at http://span.nikhef.nl/git/.

Git repositories for driving certification

The two main repositories for certification are firstboot.git and siteinfo.git.

Firstboot is a collection of machine-specific scripts that will be run on a new virtual machine, after the installation process; the name of the file must be identical to the virtual machine name. Typically the firstboot scripts will deal with adding users, setting up mounts, repositories, installing and configuring software, etc.

Siteinfo is a tree of site-info.def and friends, to be used by YAIM, the friendly middleware configuration tool.

As both of these repositories under gitosis are so-called bare repositories and therefore have no files, we need to fetch from these repositories in locations where the files should really end up. This is done by adding a post-receive hook that updates the real files whenever new data is received.

For firstboot. /srv/git/repositories/firstboot.git/hooks/post-receive:

#!/bin/sh
unset GIT_DIR
cd /usr/local/mktestbed/firstboot && git pull
echo "all updated!"

for siteinfo, /srv/git/repositories/siteinfo.git/hooks/post-receive:

#!/bin/sh
unset GIT_DIR
/usr/local/mktestbed/siteinfo/site-info-prepare.sh

The last script updates three separate trees corresponding to the master, condor and mpi branches of site-info:

#!/bin/sh

cd /usr/local/mktestbed/siteinfo

for i in vanilla strawberry chocolate ; do
	( cd $i && git pull )
	tar cfzC  $i-new.tar.gz $i .git --exclude .git .
	mv $i-new.tar.gz $i.tar.gz
done