OpenSUSE's Kiwi-LTSP: Easy Thin Client Server
Linked by Nik Tripp on Mon 2nd Mar 2009 21:40 UTC
SuSE, openSUSE IT solutions companies have been generating lots of buzz regarding thin clients basically since the early 1990s, but have yet to really penetrate into many suitable environments. These relatively cheap computer appliances carry broad promises like energy efficiency, space efficiency, and centralized maintenance and data storage. These claims could sound like the computer industry equivalent of snake oil. Kiwi-LTSP, a combination of KIWI imaging technology and Linux Terminal Server Project, is one open source solution for thin client servers.
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phoenix
Member since:
2005-07-11

Ok, there are still some serious misunderstandings going on. Lets try to establish the definitions. As you start with in math.

""In a thin-client setup, 0 CPU, 0 RAM, 0 processing is done on the client. Everything is done on the server. The client is just an I/O hub: mouse and keyboard events are sent to the server, video is sent back to the client. That's it. The local CPU/RAM is only used to boot the client. Nothing else."


As I have understood it, a thin client processes all software on it's weak CPU with little RAM. A typical thin client has 1GHz CPU and 256 MB RAM, and boots from it's server and downloads all applications from the server and runs the all of the applications or parts of the applications, on it's 1GHz CPU. "

That's a diskless client, not a thin-client.

Whereas an ultra-thin-clients doesn't process any software at all, it just handles I/O. That is SunRay. The server processes all software. On the SunRay no software is processed at all, it just shows the bitmaps that the server transmits.


That's a thin-client.

You are telling me that this is wrong? You are telling me that any thin client act the way as the SunRay does. Every thin client just shows the picture from the server, and no processing is done on its 1GHz CPU and 256MB RAM? Everything is processed on the server?


Correct. The very definition of a "thin-client" is "no local processing". All applications run on the server, and just the display is sent back to the client. The "thin-client" is just an I/O hub. It sends keyboard and mouse events to the server, and receives graphical output from the server. They have a bit of RAM/ROM to boot, and to find the server, and to establish the network connection, but that's it. After they boot, they run applications on the server, and just show the display.

Is this so? Can you show me a link to a thin client that behaves like this? (Other than SunRay). I have never found any ultra-thin-client other than SunRay.


See below for the link to Wikipedia.

Either you or my understanding of thin-clients is very wrong. Who is correct? You or me? If you can show links on thin clients working as you described, then you are correct and I am wrong. If you can not show links, then you are wrong and I am correct.


See below for link to Wikipedia.

""I don't know how many times I can say this: a dual-P3 system with 4 GB of RAM **DOES SUPPORT** 30 thin-clients, where Firefox, Java, OpenOffice.org, and Flash, are all running on the server, with just the display being shot back to the client. WE DO THIS EVERY FRIGGING DAY!! WE HAVE BEEN DOING THIS FOR 7 YEARS ALREADY!!! THIS WORKS!! Get it yet?"


And you also say that a dual P3 system with 4GB does support 30 thin clients. Where the thin clients does not process any software at all. All software processing is done on the dual P3 cpus. You claim. "

It's not a claim. Organise a trip up to Kamloops, BC, Canada, and I can show you it in action in School District 73. We use this every single day, and have done so for 7 years now. Over that time, we have replaced a few servers (dual-AthlonMP with 4 GB RAM; dual-Opteron with 4 GB of RAM), and are in the process of migrating off the thin-client setup to a proper, diskless setup. But we still have 12 schools using the original dual-P3 server setup.

But, as I said before, we are using Linux and not Windows. So the user desktop is IceWM running a small handful of opensource applications like Firefox 2, OpenOffice.org 2, TenThumbs Typing Tutor, TuxPaint, TuxTyping, TuxMath, and the KDE 2 games. We have very few problems with this setup.

We're moving away from this setup, though, as we want to be able to put Linux computers into every classroom, into the library, into the office, into the LAT rooms, everywhere in the school (~100 per elem, up to 700 in the secondaries). And we want to centralise printing, give students more disk storage, and give them access to a full KDE 3 desktop, with more applications. We also want to support CAD, animation, video, 3D, audio, and so forth. Hence, we're moving off thin-client, and to a diskless setup.

I mean, for one user, at least a 1GHz P3 cpu and 512 MB RAM computer is necessary.


For a Windows desktop, probably. For a Linux desktop, a couple hundred MHz and a couple hundred MB of RAM is plenty.

We can settle this out, if you post some links to thin-clients. Then I can read about them myself. And study the datasheets. And then I can tell if I have misunderstood the thin client concept.


A very simple, easy read through the Wikipedia article on thin-client computing (http://en.wikipedia.org/wiki/Thin_client) would suffice. ;) Here's an excerpt from the first paragraph:

A thin client (sometimes also called a lean or slim client) is a client computer or client software in client-server architecture networks which depends primarily on the central server for processing activities, and mainly focuses on conveying input and output between the user and the remote server. In contrast, a thick or fat client does as much processing as possible and passes only data for communications and storage to the server.


There's even a list of manufacturers and devices. That all act like the SunRay.

And here's the article on diskless computing: http://en.wikipedia.org/wiki/Diskless_client

Goes into detail on the differences between the two.

Edited 2009-03-05 16:55 UTC

Reply Parent Score: 2

Kebabbert Member since:
2007-07-27

Ok, Ive read your article and it seems interesting. Something is strange in my understanding though. I will check my other source up. It messes with me.

A question, you suggest diskless PCs. Is a user session tied to a specifik PC, or can you login to another PC and continue. Or do you have to restart your work?

Another question. All PCs, they can be different models and brands? You just create a Linux account that any PC can access. Some PCs might be faster or slower, so you will have different performance depending on which PC you login to?

The administration, is it easy or complicated?

This solution sounds interesting. But as we need to run Windows, I dont think Linux would suit. But it seems that you have found a near optimal solution.

So your solution consists of diskless PCs, and not thin clients. And everything works fine? Have you written more information on your solution, somewhere on the web? I would like to learn more. (Too bad we need windows)

Reply Parent Score: 2

phoenix Member since:
2005-07-11

A question, you suggest diskless PCs. Is a user session tied to a specifik PC, or can you login to another PC and continue. Or do you have to restart your work?


Yes, a logged in user is tied to that PC. They have to logout, move to another PC, and login again, in order to move around.

Think of a diskless PC that same way you would a normal PC. The only difference is that no software is installed locally, it's all installed on the server.

The one exception is when they login using the NX Client. You can suspend the connection, close the client, move to another PC, connect using the NX client, and pick up exactly where you left of. However, the NX Client login session is separate from a local PC login session. It's really only useful for access the desktop when outside of the school.

Another question. All PCs, they can be different models and brands? You just create a Linux account that any PC can access. Some PCs might be faster or slower, so you will have different performance depending on which PC you login to?


Correct. Since the OS and applications run locally, performance depends on the local hardware. This is why we have standardised the hardware for all installs, so that there isn't the whole "this station is faster than that station" issue.

However, at least with Unix, you can configure applications to run on the server and shoot the display back to the client, thus allowing you to run specific software on the server. This allows you to use 600 MHz PCs as the diskless client, but still run complex software that requires powerful CPUs. Gotta love the network transparency features of X11. ;)

The administration, is it easy or complicated?


At least for Unix setups, it's very easy. Everything is done on the server. Install software on the server, and all clients have instant access to it (NFS mounts). Add user accounts to the server, they can instantly login to any workstation (NIS). Need to swap out a dead PC? Just update dhcpd.conf to allow the new one to boot, swap in the new hardware, boot, done. Need to add a new printer or change defaults? Login to CUPS to tweak as needed. Need backups? Run an automated rsync script from a remote server every night. Once things are setup, there's very little to it.

This solution sounds interesting. But as we need to run Windows, I don't think Linux would suit. But it seems that you have found a near optimal solution.


Yes, using Windows complicates things, and is one area where thin-client/remote desktop works better.

However, you can use diskless Linux stations that just load rdesktop or krdc or any other RDP client, and have a hybrid setup. ;) That's pretty much what all the HP, WySE, and similar thin-client boxes do. They load a stripped-down WinCE or Windows XP Embedded and run the Terminal Services Client as the shell.

So your solution consists of diskless PCs, and not thin clients.


Correct.

And everything works fine?


Correct.

Have you written more information on your solution, somewhere on the web? I would like to learn more. (Too bad we need windows)


I don't think we have anything that's publically accessible, but we have a tonne of information on this setup in our internal wiki. We keep getting asked to make something available, but just haven't had the time to do so. Our IT department is under 20 people, including managers, to look after a district that spans an area 60 KM West, 60 KM East, 60 KM South-East, and 200 KM North of Kamloops, BC. ;) We manage just fine, but don't have a lot of time for extra/side projects.

Reply Parent Score: 2

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