kitting out a classroom

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by morphy_richards » Mon Mar 25, 2013 3:45 pm
Thanks for that OtherCrashOverdrive,
It turns out the problem was with the "big switch with lots of ports" thats sitting up next to my server. In desperation I changed it to one of my newer 8 pport netgear switches and everything started working! (I think it was a managed switch trying to do more complicated things than I was prepared for)

New problem is that "the application Compiz" keeps "closing unexpectedly" and my keyboard settings dont seem to have been picked up in berryterminal so I'm using US settings on a GB keyboard @"@"@"@....

Anyway, the great news is that for the small year 10 group who are about to start Computer Science, (assuming I can sort out this Compiz issue, which may turn out to be nothing much)

By the way, does anyone know how to get up that curses xwindow manager selection tool up, the one that goes somehting like ...
[1]Gnome
[2]XDE
[3]LXDE
Please choose default windown manager_
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by morphy_richards » Mon Mar 25, 2013 4:12 pm
sudo update-alternatives --config x-session-manager
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by paulknewton » Mon Mar 25, 2013 5:54 pm
I have been trying out LTSP at home and I also had problems with Compiz crashing. Some of the posts I turned up on Google seemed to suggest that this is quite a common problem. The only solution is to use another desktop environment (I tried gnome-classic which worked quite well).

Since then, LTSP has been working well. The only problem I have now is that the sound doesn't play locally, but instead plays on the server. While this is a bit of a problem for me at home, perhaps it would actually be an advantage in the classroom. 30 kids playing the latest Gangnam Style might not be that conducive to learning...:)

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by morphy_richards » Tue Mar 26, 2013 12:56 pm
Sound works nicely - comes out of the headphones socket (as opposed to the server) which is good.

Weirdness...

Geany has a funny greenish background in the text editor window, although the rest of the colours in the application (menu's etc) are normal.
Terminal window has black text on a black background :?

edit - terminal colours just a case of changing config however weird geany colours seems to be a different matter.

Little bit laggy - I should have spent a little bit more money and bought a higher spec motherboard and multi core processor. No matter though I can do that in due course and use the current set up as parts for lessons on building hardware.
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by paulknewton » Tue Mar 26, 2013 2:19 pm
Did you have to do anything special on the client or server side to get the sound working? I tried 'Sound=True' on the cmdline.txt setup but that didn't work. I'm running an Edubuntu installation on the server with the ltsp-server-standalone packages installed.

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by morphy_richards » Tue Mar 26, 2013 3:17 pm
Did you have to do anything special on the client or server side to get the sound working?
All I am doing is running Edubuntu 12.04 with 2 NIC's - pretty much out of the box as it were. I think berry terminal at one point didn't support sound but now it does... bearing in mind recent events it causes me utmost embarrassment to ask if you are using the latest version of berryterminal :oops: :P
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by morphy_richards » Tue Mar 26, 2013 4:50 pm
I'm pleased I've got this working, however the goal is to have this system implemented in each room but with each teaching room ltsp server looking to a central server for login and home directory.

I know next to nothing about networks but this is what I've cobbled together as ideas as to how I should proceed.

First I will start with a raspberry pi with dnsmasque installed. When this is configured properly it will provide me with fully qualified look up able and reverse look up able domain names for each section of my network.

Configure my main server. My main server has 2 network interfaces. One to the school network and internet and the other to my "computing.lan"
First, get the internet connection shared from school network on eth0 to computing.lan on eth1
(masquerading?)
Next, configure ldap and kerberus on the main server. (this relies on DNS and dhcpd working properly)
As each ltsp server has 2 network cards, it acts as its own router, so thats one less thing to worry about.
Finally, get a big sd card and configure a second raspberry pi to be a mail server (because email is useful if used constructively)
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by paulknewton » Tue Mar 26, 2013 8:49 pm
At the risk of looking like an idiot...I didn't have the latest version of BerryTerminal. I'm running BerryTerminal using the BerryBoot loader which downloads images of the various OS's from a remote server. I thought that the BerryBoot installer would always retrieve the latest version of BerryTerminal - it looks like I was wrong. Oh well...only a few hours wasted :)

Anyway, I'm now happy that sound does work locally. Really great work on this whole LTSP environment - it really is very impressive.

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by paulknewton » Tue Mar 26, 2013 8:51 pm
And by the way, I've been reading this thread with interest. If your enthusiasm in the classroom is anything the enthusiasm you have on this forum then I am sure the kids have a great time in your lessons.

You say that "I know next to nothing about networks..." and yet I only understand half of what you are posting. I guess that says more about me...:)

Anyway, good luck with the ongoing project. I'm only using LTSP to serve a few terminals around the house so I don't think I can give you much help with your questions I am afraid. It may be worth cross-posting on the LTSP forums for more specialised advice.

regards,
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by morphy_richards » Wed Mar 27, 2013 9:32 am
paulknewton wrote:good luck

Thanks!

Slight change in plans in terms of network configuration. I'm going to (try to) move a few of the jobs such as dhcp over to the main server instead of on a seperate raspberry pi server (I still intend to use a r-pi as dns in due course however)

I am going to work through this tutorial
http://ubuntuforums.org/showthread.php?t=926001

One health warning however,
the package referenced for install "libmd5-perl" is deprecated and not supported. You should use Digest::MD5 instead
sudo apt-get install libdigest-md5-perl
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by morphy_richards » Wed Mar 27, 2013 9:55 am
There is a bit of trickyness installing webmin

I tried wget and dkpg from the website, it failed
I tried apt-get install webmin which also failed

"The following packages have unmet dependencies.
webmin : Depends: apt-show-versions but it is not going to be installed
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution)."

So I tried
sudo apt-get -f install

All by itself, which installed webmin! (not entirely sure what happened there ... anyway, moving on)
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by morphy_richards » Wed Mar 27, 2013 12:04 pm
Accessing DHCP from webmin is problematic. It's no longer dhcp3-server, it's now isc-dhcp-server, and it doesnt show up because webmin wants to use older dhcp3 settings...

Solution is to look for dhcp under "unused modules" in webmin and edit the settings below

DHCP server config file /etc/dhcp/dhcpd.conf
DHCP server executable /usr/sbin/dhcpd
Command to start DHCP server /etc/init.d/isc-dhcp-server start
Command to apply configuration /etc/init.d/isc-dhcp-server restart
Command to stop DHCP server /etc/init.d/isc-dhcp-server stop
Path to DHCP server PID file /var/run/dhcp-server/dhcpd.pid
DHCP server lease file /var/lib/dhcp/dhcpd.leases

From this thread on ubuntu forums
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by morphy_richards » Thu Mar 28, 2013 3:28 pm
In trying to make a network for this as shown below there seems to be a catch 22...
Image[/url]

(for now) I've set the ltsp server eth1 to use dhcp to be assigned an ip address by the main server...
And I have not assigned anything for eth0 (eth0 serves the berryterminals)

On the ltsp server itself I can then successfully access the internet.

The berrterminals themselves just get "error obtaining ip address from ltsp server"

If I statically assign an ip address to the berryterminals... say ... 192.168.0.220
The internet stops working but the berryterminals are able to boot!

What might be causing this?

It could be a dhcp conflict. There is a dhcp server on the "main server" and there is another dhcp server built into the ltsp server.
I *think* I have told the ltsp dhcp server to only act on eth0 (the part that's serving the berryterminals)

It could be a firewall issue...
Disabled firewall on main server with Gufw

Still no internet and working berryterminals OR internet and no working berryterminals
Will look into this https://help.ubuntu.com/community/Ubunt ... SPFirewall when I get a chance.

Why is nothing ever easy?

Is there a less complicated solution to making it so that I will have capacity to have 30 ltsp clients in three rooms (90 in total) with a single login solution so that they can Bobby can log in in room 1 and access his helloworld.py and then go to room 2 at lunchtime, sign on with the same credentials and carry on working on helloworld.py?
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by dsmwookie » Tue Apr 09, 2013 1:58 pm
Fantastic to see a fellow educator working with such fervor. I am brainstorming a similar idea for my school and how to raise funds privately. I d eventually like the children to take owner ship of each Pi and be able to use them at home. Our area is a mixture of affluent and poor rural students, it would be a huge to provide these children with computers at their own home.

I will be actively following this thread! Keep us updated, maybe some photos once the classroom is setup.
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by R61zt » Thu Apr 11, 2013 3:31 pm
DVI and vga are bad news for rPi.
One way of getting around it would be to set up one raspberry pi with one usb keyboard usb mouse and one hdmi expensive monitor as far as getting it to accept ssh keyboard mouse and video connections from a pc. That's something I've not done, so please could others comment. Once you have one rPi working by ssh then it is straightforward to take out the sd card, dd it onto a base copy on any linux PC, and dd more copies to all your sd cards. From there your existing classroom can continue to use its existing stock of keyboards, mice and monitors for anything which can be done via ssh on a raspberry pi.

I'd been thinking that the ATX power supplies in a computer usually can spare an Amp at 5 volts. If you have a metalwork teacher who wants to get kids to solder a wire onto something, five sensible kids could solder on 1 Amp rated power supply wires to 15 raspberry pi's in a lunchtime. Or as a CDT mini-project they could have a think about any better way to supply 5V to every rPi in the classroom.
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by rurwin » Thu Apr 11, 2013 5:09 pm
R61zt wrote:DVI and vga are bad news for rPi.

VGA, yes, but DVI is just HDMI in another form. That's how I use it, on a VGA/DVI monitor. My Linux PC plugs in with VGA and the RaspPi plugs in with DVI. That way I just have to switch to the other signal source to see the other machine. If I remember correctly the cable cost £1.99.
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by morphy_richards » Mon Apr 15, 2013 10:29 am
rurwin wrote:
R61zt wrote:DVI and vga are bad news for rPi.

VGA, yes, but DVI is just HDMI in another form. That's how I use it, on a VGA/DVI monitor. My Linux PC plugs in with VGA and the RaspPi plugs in with DVI. That way I just have to switch to the other signal source to see the other machine. If I remember correctly the cable cost £1.99.


Yep.

Although some schools (like mine) have problems buying from cheaper suppliers like ebay for invoicing reasons this cable works well and is still pretty cheap.

If you look on the back of your monitors you should see something like this below. The blue port is the VGA that everyone is familiar with but the white one is DVI. Most flatscreen monitors made since about year 2000 have one of these as standard. (There are a few older monitors still in use in my rooms that don't have DVI ports, but the majority do have them, and there are more DVI ones around the school in various places. Once I can demonstrate the soundness of this to the powers that be I should be able to get permission to swap my older non DVI monitors in my rooms for other newer DVI enabled ones in, lets say, the English IT suite (as they are just connected to standard Windows PC's and so it makes no difference what kind of monitor they are connected to)

Image
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by morphy_richards » Tue Apr 16, 2013 2:58 pm
Tried updating the configuration of ltsp server to this (one NIC version) as suggested here
Image
Where, in my case the router/firewall/internet part in the diagram would actaully be main server/ school network (+ internet)

Still it only works when the main server is not plugged in... i.e. it doesn't work.

However, my main server has ip address 192.168.0.254
And my LTSP server has ip address 192.168.0.254
Which is odd because the "main server" should be assigning ip addresses and so that shouldn't happen. I have no time to spend hours investigating, work is mental.

I've now got a copy of the Linux Networking Cookbook so I will totally wipe "main server" and begin again by saving those clever year 10's from idleness and get them to work through the chapter on making a gateway. See if we can actually get a simple ltsp server with internet up and running.

I think ...

First, establish a gateway
Then check it works with ltsp
From there it's Single Sign on and then Centralised Network Directory ...

(Do I need to do make a router first? After all the school network and our computing network are totally separate entities.)

Bummer for me though, they get to have fun and learn about it and I get to do some admin and then try to work out what the hell they did afterwards.
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by morphy_richards » Tue May 21, 2013 1:45 pm
I (think I) have this cracked.

There is a relatively painless way of making a budget Linux general purpose and thin client network for teaching computer science.

You can have a single server which acts as an internet gateway, login and file manager. Seperate servers in each classroom which provide an ltsp thin client network for students who are working in that room.

For the internet / login / file server you need a computer. I happened to get hold of an old legacy HP Proliant server but you could probably press any old PC into use for this.

You need to install a second network card in this “server”. One network card plugs into your school network and provides internet. The other network card creates your own “computing.lan” network.

Install something called “Zentyal Community” on this. Zentyal is the open source equivalent of Windows Server and it’s been made to be easy to configure in the same way as Windows server is.

Setup the gateway, DNS, DHCP and “office” (it’s not office as in office apps (Word etc.) but office as in an office network)

Configure Users and Groups, make sure you select “PAM” and default shell as “Bash”

Make your classroom(‘s)Edubuntu LTSP servers It’s best if you have 2 network cards in this too, one for your wider “computing.lan” and one to make a seperate sub-net for the thin clients in the classroom.

Follow this guide to set up the Edubuntu LTSP server to authenticate and use home directorys that are on the “Zentyal” gateway / login / file server.

BUT!!!

When you come to configuring the PAM_Mount config file /etc/security/pam_mount.conf.xml

You need to add two new instructions (not one as the guide states)

Code: Select all
 <!-- Volume definitions -->
<volume user="*" fstype="cifs" server="x.x.x.x" path="%(DOMAIN_USER)" mountpoint="/home/%(DOMAIN_USER)" options="sec=ntlm,nodev,nosuid" />
<volume user="*" fstype="cifs" server="x.x.x.x" path="temp" mountpoint="/home/%(DOMAIN_USER)/SRV/temp" options="sec=ntlm,nodev,nosuid" />


Change x.x.x.x for the ip of your zentyal gateway / sso server.

NB.

This isn't exactly how I have my network setup. DNS and DHCP is provided by dnsmasq running on a raspberry pi and my gateway/firewall is a separate box running something called "clearos". I'm only using Zentyal for "users and groups".

However theoretically you should be able to do all these jobs on zentyal.
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by johndough » Wed Jun 05, 2013 9:13 am
Hi

Well ideally you could have a wireless mouse and keyboard, and the little dongle put in each machine as and when appropriate.

Although I expect they would be lost.

Remember for network cabling the requirement for 100mbs is 1, 2, 3 and 6, leaving 4 conductors.
So carefully thought out and connected, a single cat5 cable could do 2 machines/ports. Less expensive copper.
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by johndough » Wed Jun 05, 2013 9:45 am
Hi

Just something for future reference.

There is no password on the 7zip file. it is a word document.
Attachments
NIC wires.7z
no password used
(6.79 KiB) Downloaded 121 times
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by johndough » Wed Jun 05, 2013 9:53 am
Hi

Give anything fixed, like a server a fixed IP address.

This may sound a bit off, but maybe you have a local college in your area that does Cisco as an evening course, and maybe they would help out a fellow educator.

Who knows they may have old kit to donate.
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by morphy_richards » Thu Jun 06, 2013 8:18 pm
Each raspberry pi can be dual booted into either berryterminal or raspbian. Raspbian has network connectivity, internet etc via a slightly reconfigured ltsp subnet but getting it to take ldap login and mount a home directory is a little tricky at the moment
Have got high hopes though as this will give the best of both worlds once It's all fully working.
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by morphy_richards » Tue Jun 11, 2013 3:08 pm
Aftermath of CS Lesson 1
Image
Image

My brain hurts!

30 kids just made a cat6 network. Installed berryboot, set everything up. Logged in via their own details to "Lovelace" and authenticated by "Athena" And it all ... worked!

That went really ... well!
:)
Last edited by morphy_richards on Tue Jun 11, 2013 3:12 pm, edited 1 time in total.
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by rpdom » Tue Jun 11, 2013 3:12 pm
Fantastic!

It is great to see the Pi being used for what it was ultimately designed for! :)

What will the naysayers say to that?
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