A really good practice is to build debian packages inside the environment you intend to deploy in. For example, if you plan to deploy your package on an amd64 wheezy host then you ought to build and test your package install on a amd64 wheezy host. Seems pretty straight forward, eh? But lots of people miss this when building packages for debian. I’m going to go over using a tool called pbuilder to do exactly this.
After you install pbuilder you will need to do a couple things. First we need to do some setup for our host:
$ mkdir -p /etc/pbuilder/repo/
$ mkdir -p /srv/pbuilder/wheezy/
$ mkdir -p /var/cache/pbuilder/result/wheezy/
$ touch /var/cache/pbuilder/result/wheezy/Packages
$ chmod 666 /var/cache/pbuilder/result/wheezy/Packages
$ /usr/sbin/pbuilder --create --configfile /etc/pbuilder/repo/wheezy.pbrc > /var/cache/pbuilder/wheezy-base.log
Then we need to make a file named wheezy.pbrc in the /etc/pbuilder/repo/ directory:
MIRRORSITE=http://myhost/debian/
DISTRIBUTION=wheezy
COMPONENTS="main contrib non-free"
BASETGZ=/var/cache/pbuilder/wheezy-base.tgz
BINDMOUNTS="/var/cache/pbuilder/result /dev/shm"
HOOKDIR="/var/cache/pbuilder/hooks"
BUILDPLACE="/srv/pbuilder/wheezy"
OTHERMIRROR="deb file:/var/cache/pbuilder/result/wheezy /|deb http://myhost/external/ wheezy main backports"
APTCACHEHARDLINK=no
You’ll notice that I point MIRRORSITE to the my debian mirror and OTHERMIRROR to the external mirror and the build results from wheezy. Most of the other settings are important but don’t need to be covered here.
Next I’m going to assume you have a set of three files that together represent your debian source package:
- mypackage.dsc
- mypackage_source.changes
- mypackage.tar.gz
These are the necessary files required to build your debian package. You will now run the following from the directory where your debian source files reside:
$ PACKAGE=mypackage.dsc
$ TMPDIR=`mktemp -d`
$ sudo /usr/sbin/pbuilder --build --buildresult ${TMPDIR} --configfile /etc/pbuilder/repo/wheezy.pbrc ${PACKAGE} > ${TMPDIR}/build.log
You should now have three additional files in the ${TMPDIR} directory that you specified:
- mypackage_all.deb
- mypackage_amd64.changes
The mypackage_all.deb file is the file you will install on your debian host. If you are curious about the build process you can inspect the build.log file for more information.
Now what do you do if your build fails and you want to drop in as root to see what the problem is? This is where your HOOKDIR comes in handy. You will put a file named C10shell in the /var/cache/pbuilder/hooks directory that will drop you in as the root user if there is an error. The following recipe from the pbuilder site will do that:
#!/bin/bash
echo "Installing helper packages..."
apt-get install -y "${APTGETOPT[@]}" vim less
echo "Invoking shell..."
cd /tmp/buildd/*/debian/..
/bin/bash < /dev/tty > /dev/tty 2> /dev/tty
Hooks are a great way to get some extra functionality during build time like adding new apt-keys or enabling extra repo’s during build-time.
With all these tools you should now be able to build your debian source package inside a clean, stable environment that you will deploy to making your whole deployment chain better.