Green Ubuntu Desktops

A general description of the DESY operation systems and their capabilities can be found on the IT pages:

Home Directory

For each person logging into such a machine, a local home directory will be created with a few basic settings:


xuser@flc##:~$ ls -la
total 48
drwx------ 3 xuser flc  4096 Mar 16 11:55 .
drwxr-xr-x 5 root    root 4096 Mar 15 15:56 ..
lrwxrwxrwx 1 xuser flc    27 Mar 15 14:47 afs -> /afs/
-rw------- 1 xuser flc    50 Mar 15 14:48 .bash_history
-rw------- 1 xuser flc   220 Mar 15 14:47 .bash_logout
-rw------- 1 xuser flc  3771 Mar 15 14:47 .bashrc
drwx------ 2 xuser flc  4096 Mar 15 14:47 .cache
lrwxrwxrwx 1 xuser flc    37 Mar 15 14:47 Documents -> /afs/
-rw------- 1 xuser flc  8980 Mar 15 14:47 examples.desktop
-rw------- 1 xuser flc  2181 Mar 15 14:47 .kshrc
lrwxrwxrwx 1 xuser flc    35 Mar 15 14:47 private -> /afs/
-rw------- 1 xuser flc   655 Mar 15 14:47 .profile
lrwxrwxrwx 1 xuser flc    34 Mar 15 14:47 public -> /afs/
lrwxrwxrwx 1 xuser flc    31 Mar 15 14:47 www -> /afs/
-rw------- 1 xuser flc    59 Mar 16 11:55 .Xauthority

The new policy of having local home directories on Green Desktops (instead of home being in the AFS) has several implications:

In some cases, however, it may be important to have the same configuration available on each computer. In that case you can simply put a central configuration file or directory in the afs and replace the local configuration file with a symbolic link:

/home/xusername$: ln -sf /afs/ .bashrc

The f-option will overwrite an existing file of the same name, so you may want to make a backup of that file first. this solution also gives you the possibility to have configuration files for different kinds of computers.

Migrating Firefox and Thunderbird Settings

Some programs, like Firefox and Thunderbird maintain their configuration (bookmarks, history, mailaccount settings, plugins, ...) in special directories .mozilla and .thunderbird.

If you are only interested in migrating your bookmarks you can follow this guide:

Please note that you need to start the firefox you are exporting from on the pal with the command line option:

pal##$:firefox -no-remote

Otherwise pal will use your local firefox instance.

If you need to port more settings, there is guide here:

If you want to keep certain settings central, you may replace the file with symbolic link to the afs, as described above.

OpenGL Programs via ssh (CEDViewer, BBQ, ...)

On smaller computers without graphics card (i.e. IntelGraphics) there is often a problem with programs like CEDViewer or BBQ if you start them over ssh on the PAL or NAF. This affects in particular the Dell OptiPlex 760 and the new Dell OptiPlex 3020 Micro.

Before doing ssh to the remote computer you need to execute:

export LIBGL_ALWAYS_INDIRECT=1 # On your LOCAL computer

The ssh option -X or -Y for graphics forwarding is typically done automatically on DESY computers, but you can check basic graphics by running xcalc, kcalc, xeyes or another simple program.

On the remote computer this variable must not be set. However, some scripts set this variable as a bugfix. If this is the case it can beundone by either removing the statement from the script that you use on the remote machine or manually by:

unset LIBGL_ALWAYS_INDIRECT # On the REMOTE computer

After this you should be able to run the programs normally. Oviously you can also put these commands into your .bashrc and

Installation with the Software Center

There are some things to observe:

Window Manager (Unity, KDE, ...)

The default window manager for the green desktops is Unity. It is also the only one supported by DESY-IT. If you really want something else, you can simply install it from the Software Center. Beware that new systems may require a second reboot to list all packages!

Unity:  ubuntu-desktop
KDE:   kubuntu-desktop
XFCE:  xubuntu-desktop

will give you the complete respective desktop environments.

For simpler managers that don't come with a complete environment you can also install just a window manager.

On the login screen you can pick the window manager to use for the session from the small circular button next to the login field.

Large Screens via VGA, Resolution-Problems

Sometimes both inputs of a monitors are used (e.g. as second screen for a laptop). If no KVM switch is used, one of the feeding computers needs to be connected via VGA (analog) input. Adapters from DVI to VGA are very commonly available at DESY. This will not work on computers with purely digital outputs (HDMI, Displayport). Also the image quality is usually lower via VGA.

However, due to the analog connection the screen parameter detection may not work correctly. The optimal resolution and frequency needs to be found from the monitors user manual. In Ubuntu the screen configuration is usually done per and by the user via the xrandr command.

/!\ Please note that such configurations can't be set via the settings editor, as any changes via xrandr are applied later than the system settings in the startup process. Any remaining settings from a graphical editor are stored in ~/.config/monitor.xml. This file can be renamed to monitor.xml.old.

A list of available modes can be obtained with:

xrandr --query

If the desired screen resolution is not available you can add anew one and force its use.

As an example we try the Syncmaster S24B420BW with an optimal resolution of 1920x1200@60Hz. First determine some settings via:

cvt 1920 1200 60

# 1920x1200 59.88 Hz (CVT 2.30MA) hsync: 74.56 kHz; pclk: 193.25 MHz
Modeline "1920x1200_60.00"  193.25  1920 2056 2256 2592  1200 1203 1209 1245 -hsync +vsync

The new resolution mode can be created via:

xrandr --newmode "1920x1200_60.00"  193.25  1920 2056 2256 2592  1200 1203 1209 1245 -hsync +vsync

Then it is added to the list of modes by:

xrandr --addmode VGA1 "1920x1200_60.00"

And finally it can be activated by:

xrandr --output VGA1 --mode "1920x1200_60.00"

These changes are only valid for the current session and will be reverted on relogin. To make them permanent, they can be grouped into an executable script file:

xrandr --newmode "1920x1200_60.00"  193.25  1920 2056 2256 2592  1200 1203 1209 1245 -hsync +vsync
xrandr --addmode VGA1 "1920x1200_60.00"
xrandr --output VGA1 --mode "1920x1200_60.00"

It will be executed on startup by using the tool "Startup Applications" that can be run directly from dash or as part of the system configuration. Simply add the script with that program to the list of programs.

There are lots of instructions, just search for "Ubuntu" and "randr".

GreenDesktopSetup (last edited 2017-03-29 19:08:16 by OliverSchaefer)