Difference between revisions of "Cool Solution - XenApp/XenDesktop on Thinclient with only 1GB Flash"

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Please read [http://docs.univention.de/ucc-manual-1.0.html#imagegen:chapter UCC Manual Generation of adapted images].   
Please read [http://docs.univention.de/ucc-manual-1.0.html#imagegen:chapter UCC Manual Generation of adapted images].   
The official images are also explained [http://wiki.univention.de/index.php?title=Building_UCC_images here]
The official images are also explained in [[Building_UCC_images]]
Another configuration file to generate a <1GB image [http://wiki.univention.de/index.php?title=Configuration_file_for_a_reduced-sized_thin_client]
Another configuration file to generate a <1GB image [[Configuration_file_for_a_reduced-sized_thin_client]]
The image size is set at 790MB:  
The image size is set at 794MB:  
  # Image size in GB
  # Image size in GB

Revision as of 14:52, 8 August 2013

Produktlogo UCC Version 1.0

Note: Cool Solutions are articles documenting additional functionality based on Univention products. Not all of the shown steps in the article are covered by Univention Support. For questions about your support coverage contact your contact person at Univention before you want to implement one of the shown steps.

Also regard the legal notes at Terms of Service.


Thin Clients may have smaller storage devices (i.e. Compact Flash or onboard Flash) than the default 1,2G of the UCC default image.

This is an example for a thin client image for 1GB Flash supporting XenApp.

The configuration file, tested on a HP t5745(1GB), can be found at the bottom of this article.

Software packages required

Here we are going to create a small UCC Thin Client image targeting full Citrix support, tested in a HP t5745 with 1GB flash storage.

In a typical deployment, some of our customers often require these features in order of priority:

  • XenApp Session (+Firefox), including german localisation
  • Typical ressoures: Sound, Flash, HDX
  • if possible special enhancements: truecrypt
  • if also possible RDP session as a fallback

General procedure

For this we are going to need two diferent approaches, first we will use the ucc-image utility to build an image with an edited configuration file, and second we manually will install the packages left from the previous step.

Step 1 - Configuration File

This file is based on the official file for a thin client


Please read UCC Manual Generation of adapted images

The official images are also explained in Building_UCC_images

Another configuration file to generate a <1GB image Configuration_file_for_a_reduced-sized_thin_client

The image size is set at 794MB:

# Image size in GB
size: 0.794

Important packages

A graphical system is still installed, but without desktop manager:


univention-lightdm (Integration of lightDM login manager into UCC)
indicator-session (Session management, status and user switching)
indicator-power (Power state)

X window system (and input drivers)


Drivers for some video card families


Audio server:


Tools: (no sessions are installed in this step)

openssh-server (Remote secure shell (SSH) server)
ntpdate (client for NTP time servers)

Integration with the UCC domain, always required:

univention-ucc-theme (Univention theme)
univention-corporate-client (Metapackage for client systems)

This packages will be installed :

# Kernel
linux-image-generic (Linux kernel image)
# Grub
univention-ucc-grub (Grub2 configuration)

Partition scheme

/boot is set to 45MB. This is usually enough for one kernel, meaning that kernel updates should be performed by generating the image once again.

partition2_name: boot
partition2_size: 45
partition2_fs: ext4
partition2_mountpoint: /boot

The slash partition (/) will take all the available space.

partition3_name: root
partition3_size: expand
partition3_fs: ext4
partition3_mountpoint: /

The GPT would start at 2MB for alignment, and it will use 10MB of space. No "swap" partition is considered.

Now, after calling ucc-image -c thinclient-image-1G.cfg we will get the initial image

let's say in /tmp/tmprUgkUj/ucc-1.0-rev2-thinclient-image-1G.img*

2 Step - Manual installation of extra packages

The idea is to first free some space in used by apt-get and then temporarily mount additional disks so we get enough cache for packages.

That is to delete the cache of packages in

var/cache/apt/ (be sure the 'archives/partial' directory is there)

and the lists in

/var/lib/apt/lists/ (there should remain a 'partial directory in here' as well)

for that we will create two temporary filesystems

dd if=/dev/zero of=/tmp/cache-apt bs=1M count=500 && mkfs.ext4 -F /tmp/cache-apt
dd if=/dev/zero of=/tmp/apt-lists bs=1M count=500 && mkfs.ext4 -F /tmp/apt-lists

Now they can be mounted First let us mount the image in /mnt/img/

mkdir /mnt/img
mount -o loop /tmp/tmprUgkUj/ucc-1.0-rev2-thinclient-image-1G.img /mnt/img/

and free some space:

apt-get clean
rm /var/lib/apt/lists/appcenter*
rm /var/lib/apt/lists/univention*

Second, let us mount the extra filesystems

mount -o loop /tmp/cache-apt /mnt/img/var/cache/apt/
mkdir -p /mnt/img/var/cache/apt/archives/partial
mount -o loop /tmp/apt-lists /mnt/img/var/lib/apt/lists/
mkdir /mnt/img/var/lib/apt/lists/partial

with all ready, we can go into the image

chroot /mnt/img/

Once inside we can install xenapp session (~200MB in this case)

apt-get install --no-install-recommends univention-ucc-session-xenapp
apt-get clean

Now the image is full


umount /mnt/img/var/cache/apt/
umount /mnt/img/var/lib/apt/lists/
umoun /mnt/img

Thanks to the 50MB buffer that the image has other utilities as flash player, the xen package can later be added for the user itself. This is also necesary since the user has to agree with the respective licenses of these programs.

Further Info

  • 794MB image configuration file
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