Petter Reinholdtsen

I am happy to announce that finally we managed today to wrap up and publish the third beta version of Debian Edu / Skolelinux based on Squeeze. If you want to test a LDAP backed Kerberos server with out of the box PXE configuration for running diskless machines and installing new machines, check it out. If you need a software solution for your school, check it out too. The full announcement is available on the project announcement list.

I am very happy to report these changes and improvements since beta2 (there are more, see announcement for full list):

• It is now possible to change the pre-configured IP subnet from 10.0.0.0/8 to something else by using the subnet-change tool after the installation.
• Too full partitions are now automatically extended on the Main Server, based on the rules specified in /etc/fsautoresizetab.
• The CUPS queues are now automatically flushed every night, and all disabled queues are restarted every hour. This should cut down on the amount of manual administration needed for printers.
• The set of initial users have been changed. Now a personal user for the local system administrator is created during installation instead of the previously created localadmin and super-admin users, and this user is granted administrative privileges using group membership. This reduces the number of passwords one need to keep up to date on the system.

The new main server seem to work so well that I am testing it as my private DNS/LDAP/Kerberos/PXE/LTSP server at home. I will use it look for issues we could fix to polish Debian Edu even further before the final Squeeze release is published.

Next weekend the project organise a developer gathering in Oslo. We will continue the work on the Squeeze version, and start initial planning for the Wheezy version. Perhaps I will see you there?

Since the Lenny version of Debian Edu / Skolelinux, a feature to save power have been included. It is as simple as it is practical: Shut down unused clients at night, and turn them on again in the morning. This is done using the shutdown-at-night Debian package.

To enable this feature on a client, the machine need to be added to the netgroup shutdown-at-night-hosts. For Debian Edu, this is done in LDAP, and once this is in place, the machine in question will check every hour from 16:00 until 06:00 to see if the machine is unused, and shut it down if it is. If the hardware in question is supported by the nvram-wakeup package, the BIOS is told to turn the machine back on around 07:00 +- 10 minutes. If this isn't working, one can configure wake-on-lan to try to turn on the client. The wake-on-lan option is only documented and not enabled by default in Debian Edu.

It is important to not turn all machines on at once, as this can blow a fuse if several computers are connected to the same fuse like the common setup for a classroom. The nvram-wakeup method only work for machines with a functioning hardware/BIOS clock. I've seen old machines where the BIOS battery were dead and the hardware clock were starting from 0 (or was it 1990?) every boot. If you have one of those, you have to turn on the computer manually.

The shutdown-at-night package is completely self contained, and can also be used outside the Debian Edu environment. For those without a central LDAP server with netgroups, one can instead touch the file /etc/shutdown-at-night/shutdown-at-night to enable it. Perhaps you too can use it to save some power?

I serien med intervjuer av folk i Skolelinux-miljøet har jeg fått en av oversetterne som har vært med siden starten i tale.

Hvem er du, og hva driver du med til daglig?

Jeg heter Axel Bojer og er datalærer, tysklærer, oversetter med mere.

Hvordan kom du i kontakt med Skolelinux-prosjektet?

Tror jeg så en annonsering på nettet i slutten av 2001 og ville være med som oversetter. Jeg kom med på en utviklersamling og prosjektet var da helt i starten. Det var spennende å være med mens prosjektet vokste til og utviklet seg.

Jeg har «alltid» vært språkinteressert og hadde nettopp startet med Linux og tror jeg tenkte det passet å bidra. Var også glad for å få en Debian-distribusjon, og ville gjerne bruke den selv. Til å begynne med brukte jeg først Mandrake og så Debian. Og siden jeg oppdaget at det ikke var noen mulighet for å bruke den som enkeltstående i lang tid, så gikk jeg etterhvert over til Kubuntu

Hva er fordelene med Skolelinux slik du ser det?

Løsningen er forholdsvis lett å sette opp, gratis, fri programvare og gjør det mulig å gjenbruke eldre maskiner. Det fine med Debian er at det er stabilt og har en veldig stor mengde programmer. Jeg liker også apt. :-) Jeg liker også friheten ved Linux og muligheten til å delta og forme sin egen datahverdag.

Hva er ulempene med Skolelinux slik du ser det?

Skolelinux er for lite kjent og for sent ute med å gi ut nye versjoner.

Da jeg selv i hovedsak bruker Kubuntu, så kan jeg egentlig ikke svare så detaljert rundt ulempene med Skolelinux. Hovedårsaken til at jeg bruker Kubuntu er nok at da vi begynte med det mener jeg det ikke var noen annen løsning. «Vandrende arbeidsstasjon» mener jeg ikke fantes da. Dessuten ville jeg ha siste versjon, da den KDE-versjonen som var i Skolelinux den gangen var en god del enklere (tror det var KDE 2) var dårligere i mine øyne enn versjon 3.

Hvilken fri programvare bruker du til daglig?

Jeg bruker blant annet Kubuntu, LibreOffice, Thunderbird, Firefox, Kate, Comix og Konsole. Og en hel haug andre ved behov :-)

Har oversatt Comix selv, men det er jo ikke skjedd noe med Comix siden 2009, så den er det nok bare jeg som har. Om andre vil ha den gir jeg den gjerne videre. Ser at noen har startet på MComix siden jeg så på så på dette sist, så nå er jeg igang med å teste og oversette den også.

Hvilken strategi tror du er den rette å bruke for å få skoler til å ta i bruk fri programvare?

Det viktigste er å forankre beslutningen i kollegiet og med de som er ansvarlige for å vedlikeholde og bruke datamaskinene. Flest mulig bør være med på å holde det (sosialt) vedlike, kjenne og støtte prinsippene. Som enkeltmannsprosjekt blir det lett veldig sårbart, særlig når (Skole)linux ennå i stor grad er en motkultur og ikke noe en stor nok andel av beslutningstakere, brukere osv kjenner til og bruker.

Jeg tror det viktigste er å fortsette å holde fri programvare godt, oppdatert, minimere antall feil, ha en god kontakt med brukerne og attraktivt og spennende programmer. Beholde alt som er bra og ha det tilgjengelig samtidig som man tilbyr det nyeste og rareste for de som vil ha det.

New in the Squeeze version of Debian Edu / Skolelinux is the ability for clients to automatically configure their proxy settings based on their environment. We want all systems on the client to use the WPAD based proxy definition fetched from http://wpad/wpad.dat, to allow sites to control the proxy setting from a central place and make sure clients do not have hard coded proxy settings. The schools can change the global proxy setting by editing tjener:/etc/debian-edu/www/wpad.dat and the change propagate to all Debian Edu clients in the network.

The problem is that some systems do not understand the WPAD system. In other words, how do one get from a WPAD file like this (this is a simple one, they can run arbitrary code):

function FindProxyForURL(url, host)
{
   if (!isResolvable(host) ||
       isPlainHostName(host) ||
       dnsDomainIs(host, ".intern"))
      return "DIRECT";
   else
      return "PROXY webcache:3128; DIRECT";
}

to a proxy setting in the process environment looking like this:

http_proxy=http://webcache:3128/
ftp_proxy=http://webcache:3128/

To do this conversion I developed a perl script that will execute the javascript fragment in the WPAD file and return the proxy that would be used for http://www.debian.org/, and insert this extracted proxy URL in /etc/environment and /etc/apt/apt.conf. The perl script wpad-extract work just fine in Squeeze, but in Wheezy the library it need to run the javascript code is no longer able to build because the C library it depended on is now a C++ library. I hope someone find a solution to that problem before Wheezy is frozen. An alternative would be for us to rewrite wpad-extract to use some other javascript library currently working in Wheezy, but no known alternative is known at the moment.

This automatic proxy system allow the roaming workstation (aka laptop) setup in Debian Edu/Squeeze to use the proxy when the laptop is connected to the backbone network in a Debian Edu setup, and to automatically use any proxy present and announced using the WPAD feature when it is connected to other networks. And if no proxy is announced, direct connections will be used instead.

Silently using a proxy announced on the network might be a privacy or security problem. But those controlling DHCP and DNS on a network could just as easily set up a transparent proxy, and force all HTTP and FTP connections to use a proxy anyway, so I consider that distinction to be academic. If you are afraid of using the wrong proxy, you should avoid connecting to the network in question in the first place. In Debian Edu, the proxy setup is updated using dhcp and ifupdown hooks, to make sure the configuration is updated every time the network setup changes.

The WPAD system is documented in a IETF draft and a Wikipedia page for those that want to learn more.