Once you have many Debian servers, maintenance would be a problem. I just counted that I have more then 30 etch servers running in several vserver machines. Sometimes, I would like to install Debian package in all of these servers. However, it takes too much time to ssh /vserver enter into every hosts, and answer the installation questions one by one.

Thanks for the debconf(1), it’s quite easy to do non-interactive installation, since debconf already provide a noninteractive frontend. All you need to do is set the configuration before you install the package. It can be done by debconf-set-selections.

First, you have to install the package in one hosts. It would be better if you install/test the package on the same distribution version and package version. Here is an example for install localepurge. localepurge is a software for superfluous locale data, that will save you some disk space. As a Chinese, I usually don’t need Spanish, Franch and any other hundreds of different locale data.

Once you install the localepurge, you can use debconf-get-selections to dump the configuration you did.  The debconf-get-selections is part of the debconf-utils. The command would look like

# debconf-get-selections |grep ^localepurge
localepurge	localepurge/quickndirtycalc	boolean	true
localepurge	localepurge/remove_no	note
localepurge	localepurge/mandelete	boolean	true
localepurge	localepurge/showfreedspace	boolean	true
localepurge	localepurge/verbose	boolean	false
localepurge	localepurge/nopurge	multiselect	en, en_US.UTF-8, zh, zh_TW, zh_TW.UTF-8
localepurge	localepurge/dontbothernew	boolean	false
localepurge	localepurge/none_selected	boolean	false

So, these are the questions the debconf will ask you. (Since the questions has different priorities, you might not be asked for all the questions) The localepurge/nopurge line is the locales data we want to keep, so we also want to let the other servers have the same settings. You can use debconf-set-selections to set the values in the other servers.

# echo "localepurge localepurge/nopurge multiselect en, en_US.UTF-8, zh, zh_TW, zh_TW.UTF-8"|debconf-set-selections

Then you can now install the package, it will use the default value you just gave. If you need to install many servser, and do not want to see the question dialogs. You can use noninteractive fronetend to bypas the questions.

# DEBIAN_FRONTEND=noninteractive dpkg-reconfigure localepurge

This is a Tips for Debian system.