Archive for October 17th, 2012

Debian Linux how to remove Xorg, Gnome / KDE, GDM and other graphical environment packages from a server

Wednesday, October 17th, 2012

Lets say by mistake you install a package and apt installs as a package dependency a whole bunch of Xorg, GDM GNOME 2 / 3 (desktop environment) along with whole other multitude of meta packages just like, lets say xinit , nautilus, totem, gedit,remmina etc.:
Mistakenly installing a graphical environment happens common (at least in my experience as admin happed many, many times). Often installing GUI by mistake is done on already well configured productive server, serving thousand of HTTP, SQL and Mails daily.
Having a started GDM login on the server takes some from the CPU time and also is extends possibilities for security breach to the server, so as always if something is not used it is better to wipe it off …

Here are some apt-get remove commands which will (COMPLETELY) remove Xserver ( Xorg ), Graphical Login Manager (GDM), GNOME desktop environment and their surrounding stuff:


# apt-get remove xorg
# apt-get remove nautilus-data nautilus-sendto libnautilus-extension1
# apt-get remove desktop-base
# apt-get remove python-gnomedesktop
# apt-get remove gdm3
# apt-get remove totem seahorse remmina gedit-common gconf2 epipha gedit-common gconf-defaults-service xauth
# apt-get remove epiphany-browser-data evolution-webcal gconf2
# apt-get remove nautilus-data nautilus-sendto libnautilus-extension1
# apt-get remove x11-common
# apt-get autoremove --purge gnome*

Here something worthy to mention is in Debian and (its deb based linux erivatives including Ubuntu), there are the so called metapackages. For those who don’t know what a meta-package is?; it is a package linked to a group of packages. Actually the meta package itself is a pre-selected Packages ready to install / remove with apt, aptitude or rest of “intelligent” package management utils available for Debian.
Once a meta-package is installed, all linked package dependencies; be it binaries or libraries as well as the proper configurations are downloaded and installed.

Very useful thing hence is listing all install-able metapackages; to list all available metapackages in Debian Linux use:


# apt-cache search metapackage
....

.....
......

As of time of writing this post there are 276 apt installable metapackages existent on Debian Squeeze 6.0.5 Linux:


# apt-cache search metapackage|wc -l
276

Another more general way to see the basic types of metapackages, installable is via tasksel (tasksel is run and used during initial Debian Installer via install CD);
In tasksel, there are few meta-packages; Actually tasksel is very handy for sysadmins who install new servers :). Here is list of available meta-packs through it:


# tasksel --list-tasks
i web-server Web server
u print-server Print server
i dns-server DNS server
u file-server File server
u mail-server Mail server
u database-server SQL database
i ssh-server SSH server
u laptop Laptop
u manual manual package selection
u desktop Graphical desktop environment
i web-server Web server
u print-server Print server
i dns-server DNS server
u file-server File server
u mail-server Mail server
u database-server SQL database
i ssh-server SSH server
u laptop Laptop
u manual manual package selection

It is possible to also view sub-packages contained within, each of tasksel meta-packs, i.e..:


# tasksel --task-packages desktop
twm
eject
openoffice.org
xserver-xorg-video-all
cups-client
openoffice.org-help-en-us
hp-ppd
avahi-daemon
system-config-printer
openoffice.org-thesaurus-en-us
cpufrequtils
myspell-en-us
xdg-utils
pm-utils
cups
cups-bsd
xorg
iceweasel
xserver-xorg-input-all
hplip
desktop-base
alsa-base
libnss-mdns
browser-plugin-gnash
xterm
anacron
alsa-utils
cups-driver-gutenprint
foo2zjs
hpijs
gimp
menu
kerneloops
openoffice.org-gcj
libgl1-mesa-dri
foomatic-db-engine
Actually using tasksel is much more “intelligent” way to remove GNOME, GDM and Xorg from a server. It will completely wipe out everything previously installed for running Desktop Environment on the host.
To remove desktop environment with tasksel:


# tasksel remove desktop

Ncurses progress bar will appear displaying all removed packages …
In my case, during trying to figure out what packages I need to remove ImageMagick as long as few other packages got removed as dependencies so I had to install them over with:


apt-get install --yes imagemagick libice6 php5-imagick libxvmc1 \
libzbar0 libxt6 libsm6 libxres1 libxtst6 libxvmc1 x-ttcidfont-conf libxxf86dga1

For people who need to remove KDE desktop environment from a host to be used as a server, check out KDE meta-packages:


apt-cache search metapackage|grep -i kde

You can remove all KDE related meta-packs within a bash loop, like so:


for i in $(apt-cache search metapackage|grep -i kde|awk '{ print $1 }'); do \
apt-get remove $i; done

It is also usually good idea, once all packages are removed the RC Remove Candidate deb packagse are removed too – if you don’t know what is RC I suggest you read my previous post here

Removing all rc‘s from system can be done with:


# for i in $(dpkg -l | grep -i '^rc' | awk '{ print $2 }'); do \
dpkg --purge $i; \
done

Though, I tested this if you follow my tutorial be careful, something might break and some essenail package or lib for (your custom) services might be removed. Be careful what is offered to uninstall only approve it if you’re 1000% sure; Please don’t count me responsible if apt- removes something which breaks your productive server 🙂

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Posted in Linux, System Administration, Various | 2 Comments »

Debian Linux: dump and migrate identical packages with (dpkg) from server 1 to server 2 /A common sysadmin dpkg package dump mistake

Wednesday, October 17th, 2012

Debian dump and migrate dpkg common mistake, copy migrating deb identical packages between Linux hosts

Over the last years it happened multiple times to me to migrate identical Debian installation (with identical services) hosts, running identical Debian version and identical installed packages and configs in order to move Old (hardware) servers to newer (harware) hosts. I will call for simplicity first system from which migrating “copy from host” and second “copy to host”. Moving exact number of installed packages between “copy host” and “copy to host” systems can probably be done in many ways but I personally prefer using a single method – using dpkg to dump all deb packages list on the system in a file; move this file to “copy to host” and there use a tiny for loop bash (cycle) + dpkg to install all listed packages. Last time I’ve done this is just 2 days ago while I was “Resurrecting” Pc-Freak machine using my l337 h4x0r zk!1lZ and same good old well tested logic 🙂

I used following to dump all packages;


# dpkg -l | awk '{ print $2 }' >> /root/packages_list.txt

This though dumps all deb packages, along with all current installed ones dumps also, package names of debs, which used to some point in time be existent on the system – removed and the belonging package configs were kept on the system (in other words a tiny part of the package left installed on the system, just in case if one needs to install and use package some time in lets say short future).

This keeping of package name configs and skele files in Debian is called in “dpkg language”
(rc – Remove Candidate). While doing operations dpkg package manager marks different packages with different flags, so rc flags are set once the package is apt-get remove-d or dpkg -r packagename is done over a pack.

For unfamiliar with Debian’s dpkg, package system flags, check out man dpkg. Just to give example of rc, here are few packages marked as RC (Remove Candidates):


# dpkg -l |grep -i ^rc|head -n 3
rc acidrip 0.14-0.3 ripping and encoding DVD tool using mplayer and mencoder
rc airsnort 0.2.7e-2 WLAN sniffer
rc airstrike 0.99+1.0pre6a-4 2d dogfight game in the tradition of 'Biplanes' and 'BIP'

The reason, why this package are still “remembered” by dpkg is they were not purged after install- i.e. (dpkg –purge whatever-packagename) was not issued over ’em.

With this said in mind, it is common mistake I make while making a dump of all packages to also dump inside list names of packages mared as RC, e.g.:


# dpkg -l | awk '{ print $2 }' >> /root/packages_list.txt

Later I install often install every packages inside /root/packages_list.txt as for exmp., pointed out in my previous article Debian Linux Squeeze 32 bit i386 to amd64 hell just to later find out I have numerous (daemons), on the old “copy from host” but are installed and ran by dpkg (config scripts) on the 2nd “copy to host ….

Thus to prevent this I recommend people, always think well before doing something (something I often miss).

Thus it is much better to dump only packages obtaining, the ii (dpkg flags).
Here is example of few packages which have ii dpkg package flags:


# dpkg -l | grep -i '^ii' | tail -n 3
ii zip 3.0-3 Archiver for .zip files
ii zlib1g 1:1.2.3.4.dfsg-3 compression library - runtime
ii zlib1g-dev 1:1.2.3.4.dfsg-3 compression library - development

Probably other people just like me, did same mistake as me to dump all ever available package names on the system and later ended up in same situation, where have to remove packages and stop services from running on system boot …

Thus the “correct” way to dump only installed and configured ones debs having the II system flags is by:


# dpkg -l | grep -i '^ii' | awk '{ print $2 }' >> /root/only_installed_deb_packages_list.txt

Then the rest of package copy from “copy from host” machine 1 to “copy to host” 2-nd machine is to be done by uploading /root/only_installed_deb_packages_list.txt to 2nd host with ftp, sftp, scp whatever transfer proto and running on copy to host:


for i in $(cat /root/only_installed_deb_packages_list.txt); do
apt-get install --reinstall $i; done
 .

Generally this will make programs on copy host, be on copy to host.
Enjoy 🙂

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Posted in Linux, System Administration | 2 Comments »