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Archive for the ‘Distribution’ Category

Making different openSUSE liveCDs

December 29th, 2012 by

In my last post I explored the various liveCD creation methods out there, and I really wanted to try one of the others for openSUSE.
Thus I did so today in less than two hours.
I used Debian’s liveCD as basis and replaced the userspace with an openSUSE-11.4-GNOME-liveCD one (later ones likely do not work as systemd is not compatible with old 2.6.32 kernels).
And it worked like a charm. If you want to try it yourself, you need openSUSE and an empty directory with 5GB free space. Then you do as root:

zypper -n in clicfs squashfs cdrkit-cdrtools-compat
wget -O Makefile http://lsmod.de/bootcd/Makefile.aufslive.11.4
make

This will take a while to download the two isos and then at least another 3 minutes for the processing.
If that seems too hard for you, you can just download the finished iso and try it with qemu-kvm -m 1000 -cdrom xxx.iso

Do not let the debian logo in the bootloader confuse you. Just press enter there.
When running in KVM from RAM, this boots up in 18 seconds, while the original iso took 33 (measured from pressing enter in bootloader to the time the CPU load goes down). However, with physical media the difference will be less pronounced. Some of the difference comes from the faster gzip decompression. Unfortunately debian’s kernel does not support squashfs-xz, so I could not try that.

I hope in the future, we will have aufs patches in our normal openSUSE kernels and add an aufs-live mode to kiwi. That would help with the problems we hit with clicfs when memory runs out (and it can not be freed by deleting files either).

LiveCDs

December 27th, 2012 by

As few of you might know, I made my own SUSE-based LiveCDs a while ago, using (like Knoppix) cloop compression with iso9660 and my own kernel code for file-based overlay to make it writeable. You might be amazed at how fast it runs in KVM. However, the kernel part has bit-rotten and there are other techniques out there today, so I took a look around at how others do their LiveCDs.

But first some broader overview. To make a LiveCD, the biggest problem is that CDs are not writeable (and even modern Flash devices do not want to be written too much). Embedded devices using flash had the same problem. Various approaches have been used in the past to solve this:

  • adapt all software to write into ram-disks e.g. by having symlinks (hard to create and maintain)
  • load all software into RAM (only for small distributions)
  • use file-based overlaying such as unionfs or aufs to have software write into RAM (lsof, pwd, and hardlinks can be tricky)
  • use block-based overlaying (problem: can not easily free disk space again)

Also compression is used to fit more onto a CD. And interestingly, this usually also speeds up booting because it is faster to read 10MB off a CD and decompress it into the original 30MB than to read 30MB from such a slow medium.

Now, to the distributions.

  • openSUSE has the classic DVD installs that use special installation-images and run in RAM and then there are the real LiveCDs that are created by our kiwi tool, use block-based overlaying and LZMA compression of a ext3 by means of our FUSE-based clicfs.
  • All of the other distributions use squashfs for compression. Mageia employs dracut for initrd and unionfs for file-based overlaying
  • Debian uses aufs for file-based overlaying
  • Ubuntu uses overlayfs for file-based overlaying
  • Fedora uses an ext4 filesystem image contained in a squashfs with dm-snapshot for block-based overlaying, thus being most similar to openSUSE

I also spent some time benchmarking (on my AMD A10-5800K) the various technologies with a simple script using Debians uncompressed rootfs of 495132 KiB as data.
squashfs supports three different compression methods: lzo, gzip and xz (aka LZMA).

  • squashfs-lzo: size:220992 compression:11.1MB/s decompression:134.4MB/s
  • squashfs-gzip: size:203328 compression:15.5MB/s decompression:88.9MB/s
  • squashfs-xz: size:176064 compression:6.5MB/s decompression:22.5MB/s
  • cloop(gzip): size:213348 compression:16.2MB/s decompression:49.6MB/s
  • clicfs(xz): size:185300 compression:16.7MB/s decompression:18.2MB/s

This has some surprises: even when using the same compression method, sizes can differ by 5% and speed can differ even more.

If you want to compare numbers on your system, memory throughput is also interesting:
# dd if=/dev/zero of=/dev/null bs=1M count=100000
104857600000 bytes (105 GB) copied, 12.4499 s, 8.4 GB/s

Overall, clicfs is performing OK, considering that it already takes care of the overlaying, but for my own LiveCD I would prefer Debian’s method and I am wondering how it would work.

Run X2go thin-client using kiwi-ltsp

September 27th, 2012 by

Recently, came across x2go packages maintained by Jan Engelhardt for openSUSE and other distributions on open build service. As openSUSE Education Li-f-e has great LTSP integration thanks to KIWI-LTSP, I decided to check out how x2go can fit in with this existing thin-client computing solution.

“x2go is an open (GPL/AGPL) source “server based computing” project. Combining the advantages of existing systems it features ease of use, performance and scalability. x2go provides you with access to your desktop – from within your own network and via the internet. x2go is not limited to particular hardware, it supports a variety of devices and architectures.” -from their website.

Some of the features/benefits of x2go that are not available on LTSP are:

* Remote login from within local lan and internet from any OS
* Session persistence, you can disconnect session from one client and continue where you left off from any other client
* Low bandwidth usage
* Session sharing with other users
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How kiwi can help to cleanup your system

September 25th, 2012 by

After some iterations of updating the system with zypper dup or yast and some years of service with the system you will find out that there is a lot of dust which is obsolete or has been forgotten. Recently I had the problem that I need to move my 32bit system to a 64bit system and thus the way to go was to migrate the running system into an image description, build a 64bit image from it and install that on the 64bit machine. But the most important part was to cleanup the running system and find out what it really contains. The report kiwi migrate created here was helpful and so I think it might be helpful for others too. Just call:

kiwi –migrate mySystem

It will end up with some data below /tmp/mySystem which of course can be removed at any time without any risk. Most interesting is the html report generated which you can view with any browser. So far kiwi collects the following information:

  • kernel version and kernel specific kmp packages
  • hardware dependent packages
  • installed gem packages
  • repository checkouts
  • rpm packages installed multiple times
  • rpm packages which could not be found according to the current repo setup including version and repo information
  • tree of modified files, packaged but changed
  • tree of custom files, those which doesn’t belong to any package or other part of the bullet list

basically the use case of kiwi migrate is to migrate the running system into an appliance description but I’m not there yet. There is still room for improvement but I think it still can help to cleanup the system and to see what is installed on the system and not managed by a package manager

I have tested this since openSUSE 11.4

Remember to have fun 🙂

Updates for openSUSE Edu Li-f-e

September 15th, 2012 by

With the release of openSUSE Edu Li-f-e 12.2, we also have new KDE waiting in the official update repository. To resolve a couple of conflicts you will need to add Education:update repository before running yast2 online_update.

Follow these steps:

- Add Education:update repository by using this 1-click install, remain subscribed to the suggested repositories or via command line:
  zypper ar obs://Education:update/openSUSE_12.2 Education:update then run yast2 online-update.
 - select replacement for kioaudiocd
 - select deinstallation of yast2-qt-branding-life
 - Proceed with the update

Announcing the release of openSUSE Edu Li-f-e 12.2

September 14th, 2012 by

openSUSE Education team once again presents Li-f-e (Linux for Education) built on hot new openSUSE 12.2 including all the post release updates. As always this edition of Li-f-e comes bundled with a lot of softwares useful for students, teachers, as well as IT admins of educational institutions. Apart from stable versions of KDE and Gnome, Cinnamon is also available.Sugar desktop suite makes a comeback thanks to the work of Xin Wang packaging it. Li-f-e also give full multimedia experience right out of the box without having to install anything extra. The live installable DVD iso stands at 3.3G as an incredible array of softwares from open source world are available on it, we have not just bundled them in, but have tried to integrate it with the distribution to give everything a seamless feel.

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live-fat-stick

September 13th, 2012 by

So you got a bunch of different openSUSE 12.2 live isos downloaded, to test them on a real machine you have to either burn them to CD/DVD or create live USB stick. Creating CD/DVD is a total waste after booting it once or twice. Creating bootable USB stick is a better thing to do, however openSUSE Hybrid iso creates USB stick that is not usable for any other purpose and the remaining space is locked till you make another partition, and even then the partition is not available on windows(tm).

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Testing LTSP on openSUSE 12.2

August 23rd, 2012 by

With openSUSE 12.2 almost here, we have been working hard to get LTSP experience on this release better than ever. Thanks to the power of KIWI and some great scripting by Alex Savin, KIWI-LTSP has a lot of new features and improvements.

Here is how to get started:

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Repository GNOME:Contrib is dead

June 29th, 2012 by

An announcement for GNOME users in openSUSE: the repository GNOME:Contrib is now dead. This used to be the development branch of GNOME packages living in Contrib. Packages previously in this repository have all been pushed to Factory. If this is in the list of your subscribed repositories, please remove it now (using zypper rr <reponame> or from YaST, etc.), because the repository itself will be deleted from the download.opensuse.org server shortly.

A New Font Repository

May 21st, 2012 by

what do you need when you write some text? Content, of course. Apart from your content you need an additional part to make it a shiny contribution: fonts! If you don’t know already: we have now a new repository dedicated just to fonts.

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