Many people seem to be afraid of mixing stable with testing, but frankly, testing is fairly stable in its own right, and with proper preferences and solution checking, you can avoid the “stability drift” that puts your core packages on the unstable path.
“Testing is fairly stable??”, you ask. Yes. In order for a package to migrate from unstable to testing, it has to have zero open bugs for 10 consecutive days. Chances are that, especially for the more popular packages, somebody is going to submit a bug report for an unstable version if something is wrong.
Even if you don’t want to mix the environments, it’s still nice to have the option there in case you run into something that requires a newer version than what is in stable.
Here’s what I recommend for setting this up:
First, create the following files in
# 500 <= P < 990: causes a version to be installed unless there is a # version available belonging to the target release or the installed # version is more recent Package: * Pin: release a=stable Pin-Priority: 900
# 100 <= P < 500: causes a version to be installed unless there is a # version available belonging to some other distribution or the installed # version is more recent Package: * Pin: release a=testing Pin-Priority: 400
# 0 < P < 100: causes a version to be installed only if there is no # installed version of the package Package: * Pin: release a=unstable Pin-Priority: 50
# 0 < P < 100: causes a version to be installed only if there is no # installed version of the package Package: * Pin: release a=experimental Pin-Priority: 1
(Don’t be afraid of the unstable/experimental stuff here. The priorities are low enough that it’s never going to automatically install any of that stuff. Even the testing branch will behave, as it’s only going to install the packages you want to be in testing.)
Now, creating a matching set for
stable.list: Copy from your original
/etc/apt/sources.list. Rename the old file to something like
testing.list: Same as
stable.list, except with
unstable.list: Same as
stable.list, except with
unstable, and remove the security lists.
experimental.list: Same as
unstable.list, except with
You can also add a
preferences.d (use a priority of 1), though this moniker will tend to expire and disappear before the next stable cycle. In cases like that, you can use
http://archive.debian.org/debian/ and “hardcode” the Debian version (etch, lenny, etc.).
To install the testing version of a package, simply use
aptitude install lib-foobar-package/testing, or just jump into aptitude’s GUI and select the version inside of the package details (hit enter on the package you’re looking at).
If you get complaints of package conflicts, look at the solutions first. In most cases, the first one is going to be “don’t install this version”. Learn to use the per-package accept/reject resolver choices. For example, if you’re installing foobar-package/testing, and the first solution is “don’t install foobar-package/testing”, then mark that choice as rejected, and the other solutions will never veer to that path again. In cases like these, you’ll probably have to install a few other testing packages.
If it’s getting too hairy (like it’s trying to upgrade libc or the kernel or some other huge core system), then you can either reject those upgrade paths or just back out of the initial upgrade altogether. Remember that it’s only going to upgrade stuff to testing/unstable if you allow it to.
EDIT: Fixed some priority pins, and updated the list.
/etc/apt/apt.conf.d add the following file
/etc/apt/sources.list.d – add urls for testing / unstable sources
deb http://ftp.de.debian.org/debian/ stable main contrib non-free deb-src http://ftp.de.debian.org/debian/ stable main contrib non-free deb http://security.debian.org/ stable/updates main contrib non-free
deb http://ftp.de.debian.org/debian/ testing main contrib non-free deb-src http://ftp.de.debian.org/debian/ testing main contrib non-free deb http://security.debian.org/ testing/updates main contrib non-free
and then install what you need with
apt-get -t testing install something
Be very very careful if you install stuff that has plenty of dependencies. Preferably don’t do this on production.
You can as well try your luck at backports or similar repository.
Define the default level that the system should ‘safe-upgrade’ to in the /etc/apt/preferences file:
There’s a lot you can do with apt_preferences but for the sake of simplicity…
I needed to install a single package (autoMysqlBackup) that was only available in Testing. The solution was to add the following to /etc/apt/preferences:
Explanation: Uninstall or do not install any Debian-originated Explanation: package versions other than those in the stable distro Package: * Pin: release a=stable Pin-Priority: 900 Package: * Pin: release o=Debian Pin-Priority: -10
With multiple repositories added to /etc/apt/sources.list aptitude will now only upgrade to your specified release even though the later release repos are listed (in this case ‘stable’).
deb http://mirror.aarnet.edu.au/debian/ lenny main deb-src http://mirror.aarnet.edu.au/debian/ lenny main deb http://mirror.aarnet.edu.au/debian/ squeeze main deb-src http://mirror.aarnet.edu.au/debian/ squeeze main
So to install that package, all you have to do is:
$ aptitude install -t testing packageName