Desktop Guerrilla Tactics: a Portable Thin Client Approach

Roll out a desktop Linux pilot project quickly without disturbing the legacy desktop OS.
Conclusion

We strongly feel that the possibility of a graceful exit from the pilot positively affected the outlook of both management and users. So far, they have opted not to use that exit. End-user response has been positive, and some have even offered usability suggestions.

An unexpected side benefit has surfaced: it has allowed the company to observe and document the speed, ease and costs of deployment and support of this approach. This, in turn, provided management with the option of considering its use as a critical component in an enterprise-wide, disaster-ready infrastructure. Thus, without irrevocably committing the company to large-scale migration, prototype systems have been seeded across the organization and are being nurtured by champions.

The current strategy options include continuing deployment of these terminals to increase and improve both support skills and user familiarity. We are confident that this diffusion of skill sets and attitudes across the enterprise will enhance the future decision-making calculus and further bolster Linux as a practical and superior alternative.

William Yu takes charge of information planning and security at SVI Technologies, Inc., a Manila-based IT outsourcing company. His fields of interest include high-performance computing, network security and information systems planning. He also is a faculty member at the Ateneo de Manila University.

Dominique Cimafranca is a Linux IT specialist for IBM Philippines. He has implemented Linux in the whole range of hardware platforms from IBM for several enterprise customers. He has been writing about Linux and technology issues for the past three years.

______________________

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Client hardware underutilized

Sammy's picture

It seems like an interesting solution. Issues I have with it, VNC does not encrypt it's traffic. Solution to that, SSH tunneling - hard part would be setting up the session (each user has to log in with a password and username first?). The next issue is the fact the thin clients hardware is entirely unused, this seems like a waste and pushes more load onto the server. Why not use something like Xubuntu on the clients (designed to be thin) and handle the home directories on the fat server? I am sure you can get the client to ask for updates if needed, although this does require the use of a hard drive.

At the very least I would add the SSH tunneling to ensure some measure of security.

At SSH would be great. After

PC Remote Support Software's picture

At SSH would be great. After all these years, developers of vnce could have added at least some basic form of encryption. It's understood that it's a free project althiough they do have a purchase version now. But the software would reach even more widespread use if there was at least some encryption. Maybe they were saving this for the paid version and never added it to the free version on purpose. There are other flavors of vnce avaialable that do have encryption but I hear the data stream slows down greatly though. It's a trade-off.

FYI

Evosys's picture

Thin clients are very useful, and I haven't found LTSP difficult to set up in the past.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

Diskettes ? Are you kidding ?
Try a real thin client: http://pxes.sf.net

Easy

Evosys's picture

Disks are easy to use for a demonstration set up.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

actually, there is nothing stopping us from installing this system on a bootable CDROM or flash storage device.

another solution would be to save the image in the server and configure systems with bootable PXE LAN cards. we just configure the PXE server to serve both the kernel and the filesystem (ramdisk) separately.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

We at our installation are trying to use Openoffice solution over thin clients running off RedHat 9 servers (low end/midrange). We are using xdcmp and find speeds terribly slow. After reading about your VNC experiment I have some queries :
a) Through VNC how can separate user logins be handled ? VNC only allows using the console X Screen isnt it. So wont there be a situation wherein every user views each other's work ?

Kindly reply. If not difficult email to mohan@hcbom.bom.nic.in

Thanks in advance..
- Mohan

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

that's the thing about this solution. it does support multiple session logins. this is done by using a combination of xdm/gdm/kdm , vnc and xinetd. try it out. good luck!

Important aspect: Sound

Anonymous's picture

Although there is generally not a business case for having sound on a workstation, how was sound addressed? I don't just mean the odd beep here and there, I mean full multimedia and such.

Re: Important aspect: Sound

Anonymous's picture

The MuNAS solves the problem that the X Window system does not support the transformation of audio data. It makes the thin-client/server computing model in Linux be capable of executing multimedia applications. The audio data generated by Open Sound System (OSS/Free ) compatible audio applications which are executed in the terminal server can be transferred to X-terminals. The MuNAS is designed and developed for the thin-client system. With MuNAS installed, you can execute multimedia applications in the terminal server and listen for the sound from your X-terminal. Otherwise, these applications must be executed mutely in the thin-client architecture of Unix.

you can get more information on this web site
http://www.advancedthintech.com

Regards,

howie
Innovation Group
Advanced Thin-client Technology Inc.

Re: Important aspect: Sound

Anonymous's picture

At first blush, I find it hard to trust any Linux software whose extremely ugly web page was written under Windows -- with Frontpage, no less!

Re: Important aspect: Sound

Anonymous's picture

Maybe you can check again ,We have change that~@@

Re: Important aspect: Sound

hip2b2's picture

in this version, no sound. just your usual beeps.

a possible solution would be to grab what LTSP does for sound. that would be a good start. but, a topic for another article ;-)

Re: Important aspect: Sound

Anonymous's picture

There are sound packages that stream the sound to the clients. Look at the LTSP site for some info.

Re: Desktop Guerrilla Tactics:Bandwidth requirements

Anonymous's picture

You would be shocked at how little bandwidth is required to do such a thing. For efficiency disable all screen savers and set the desktop background to a neutral wallpaper with no fancy stuff. I run on machine with 120 users on it and the bandwidth used is about 200k average. X is incredibly efficient as long as you can keep the necessary screen refresh rates down by not running too much eye candy.

I do something similar for test rollouts and even production

Anonymous's picture

When setting up a thin client environment I generally use a straight x setup running xdmp. I do not run the LTSP package but I do use their sound utilities. The problem with LTSP I feel is the complexity and the lack of configuration flexibility. I also cannot have 200 people logging into a box and pulling a kernel across the network all
at the same time in the morning.That being said one thing I use alot is a slax cd distro that I did one little hack to. I added a line at the bottom of rc.local that uses wget to grab a shell script
from a internal web server and execute it. The wget command passes the mac address of the nic eth0 to a php page on the internal web server. This php page either will pass a default shell script that contains the flollowing.
/usr/X11R6/bin --query linuxserver.mydomain.com
Or it can pass any other configuration based on the mac address that it needs to. The beauty in it is that you never have to remaster a cd yet you have full control over of the client configurations. Say a month from now you wish to move some clients to a new server. I just point the script the get from the web server to a different server and bingo they are instantly migrated. Or If your server gets to loaded you can you can just push half of the clients to a new server. It also allows you to do
automated network mounts, printer configs, network settings,sound etc. I am willing to bet that using this method I can bring up a 500 workstation enterprise in a single day. It is also safe that if for some reason I wish to revert back I just remove the client cd.

Re: I do something similar for test rollouts and even production

hip2b2's picture

actually, that is not such a bad idea. the current version of the floppy system does contain wget. it shouldn't be very hard to grab the VNC server settings from a web server within the network.

this is will definitely try out. thanks for the idea.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

If you want a simple thin-client system, try pilotlinux. (www.pillotlinux.nl). It is a Morphix based cd that transforms the pc into a thinclient.

  • Download the iso
  • Burn it to cd
  • boot PC from cd
  • Connect to a server

The current beta (version 2.0 beta3) supports RDP (microsoft Terminal Server). The next beta (available at the end of the week) also supports VNC and X.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

cool. what does this CDROM distro contain aside from the RDP client (rdesktop, i suppose)? it is meant for regular end-users like knoppix or is it for high performance computing dudes?

as a matter of fact, i have a single floppy system that does RDP too. you can complile rdesktop with svgalib too. as a matter of fact, it can still fit on the vnc floppy in this article. email me if you are interested.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

It's meant for ease of use :-)
Currently we are running PilotLinux on a Pentium 166 with 64 MB ram (no HDD, just a cdrom-drive).

PilotLinux contains:

  • the knoppix hardware detection software
  • A complete X-windows system
  • Special software to make it possible to connect to the server without user intervention
  • Special GUI software to make the cd easy to use

A new beta is being tested and almost ready for upload. It contains also support for VNC (4.0) and the X-protocol.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

oh and one more benefit.... CDROMs last longer than floppies!

cheers!

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

True. But remember, the article states that not all of the clients have CD drives.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

true. but, don't you think we should start worrying about the day when floppy drives will be phased out? ;-)

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

I have a very very ancient PowerPC which runs MacOS 8.x and cannot be upgraded to MacOS X :-( ... so I wanted to know if I can make a floppy such as described in the article for it? Or am I just trying to raise the dead?

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

yup. can you install Linux PPC on that mac and install the necessary software. but, i would not be able to do much.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

to the Mac user: probably not, as there would be extra steps involved in recompiling a PowerPC-based Linux kernel. An easier approach may be to re-partition the Mac hard drive to give yourself a little room for a PowerPC-based Linux-distribution, such as YellowDog Linux. Properly set up, you could use yellowdog as a "slightly-thicker" client to access the main Linux server.

jimm@digitalmouse.org

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

We've used Quantian (a Knoppix-based bootable CD distro) to very quickly set up such a fat-server, thin-client environment. It's incredibly easy because Quantian comes with both LTSP and openMosix (for clustering). The steps are trivial:

1. Download Quantian.
2. Burn ISO to CD.
3. Determine NIC types on thin clients.
4. Go to BusyBox and create boot floppies.
5. Boot Quantian on fat-server.
6. Start terminal server and clustering apps.
7. Input IP address range for clients.
8. Boot clients from floppies.

Our server wasn't particularly fat (1GHz AMD Duron with 1GB RAM on a 100MBPS ethernet) and we only went up to 3 clients, but there was no drag on the server with that set up. The "downside" to Quantian is that it is a math/stats distro and lacks OpenOffice (uses Koffice by default).

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

More recent versions of Quantian include OpenOffice.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

I believe Quantian has put back OpenOffice, so it may have it now.

There is also ClusterKnoppix as well. And don't forget that once installed to disk, the lack of OpenOffice or any other app is easily solved with Apt-get. The client-server setup makes it easier to install to disk, since you are only installing the server, the clients still boot from the floppy or cd (or ethernet card).

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

thanks for pointing this out. as a matter of fact, the Knoppix people have already placed in "terminal server" functionality into the base knoppix distribution.

quantian does add the novelty of being about to "farm" out processes to other machines in the quantian cluster. i presume using openmosix. very nice!

i am just curious what does quantian and knoppix use for its terminal server functionality? i haven't actually tried it myself yet. it is vanilla X-windows or VNC?

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

It's X. The thin-client looks just like you've booted the Knoppix CD.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

shucks. now that would be bandwidth heavy. well, can't have everything. hahaha.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

There's an option to VNC that places a lower burden on the server: run X on all the workstations with a display manager (gdm or xdm) running on the server. Performance is quite good over 10MHz ethernet.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

qed's picture

This is an interesting approach, I am dubious about the responsiveness of a straight vnc client server approach based on personal experience with vnc.
Does anyone have any other first hand experience with vnc?

q

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

if you are using a LAN the performance is spectacular. the sluggishness typically noticable in thin client solutions is hardly noticable.

for a low bandwidth links like VPN over unrealiable internet or a 28.8kbps dial-up which we used in our tests, there is some sluggishness.

generally, our users find the performance acceptable in both scenarios. in the LAN scenario, they hardly notice it is a thin client. i would like to note that we are using tightVNC for this with the low-bandwidth optimized tight encoding.

however, in our setup, the resources limits were configured on a per user basis effectively limiting the amount of RSS and CPU time per user. this prevents the scenario were one user hogs the resources.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

this was actually one of the original proposal. however, the goal of the project was to have a "bandwidth"-friendly system.

currently, the system uses tightVNC and works pretty well on a 28.8kbps dial-up line. i have not tested it on anything lower since i do not have a slower modem lying around.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

Its good to know that you got good results from your approach. I have tested VNC before on a 100Mbps LAN but I thought it was not that good. I encountered some minor screen redraw problems but I admt it was a usable system. Maybe its time to revisit VNC again (using tightVNC).

I downloaded your disk image and will try it out myself.

Good luck to your project. Maybe we can share user expereinces as I also have a project here in Davao where I helped an NGO migrate to an LTSP system. It has been running since December 2003.

Holden

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

Yes, the compression on TightVNC is much better. I use it regularly to
move my desktop (applications humming along intact) from work, to
my home office, to the coffee shop and from machine to machine at work.

Those are all lan or broadband class connections, but i run a graphics rich
desktop.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

hip2b2's picture

thanks for show of support.

you know how to contact me if you need some tips. i currently have one production system (mainly for mainframe support, lotus notes and web browsing) and a new one being deployed.

we are having wine/SMP problems on the newer system. grrr.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

I think that forgot some details about the test. For example, server configuracion (memory, processor speed, hardisk, etc), network topology, how many clients connected to the server, network performance, etc. Without that information, the test have little value for a third party.

Re: Desktop Guerrilla Tactics: a Portable Thin Client Approach

Anonymous's picture

I think the article was more focused on the human user side of the project. with some technical details thrown in.

Machine Specifications [was Re: Desktop Guerrilla ...]

hip2b2's picture

i apologize for leaving out the details on the machine specification. as somebody already mentioned, this is mainly focusing on the "human" aspect of the project. but i understand the need.

the "fat" server is actually a Intel Pentium III 733MHz with 512MB RAM. it is not quite as beefy as i would like it to be. during the tests i was able to cram 10 users into the system mainly using their web browsers, x3270 emulators and Lotus Notes (on Wine). however, running openoffice will not allow me to run that many users.

the "thin" clients tests were are low as a Pentium classic 75Mhz with 8MB RAM. i suppose we can even go lower.

hope this helps.

Machine Specifications [was Re: Desktop Guerrilla ...]

Anonymous's picture

Thanks for the additional info.

That sounds like a reasonable setup, fitting the intended budget here. Judging by your tests, what would you consider the bottleneck? CPU load, hard disk performance or memory usage?

Thanks again,

Blaze

Machine Specifications [was Re: Desktop Guerrilla ...]

hip2b2's picture

the main bottleneck is memory. the only cases were my CPU maxes out are cases when there is not enough memory and the system starts to page. however, particular applications need more CPU than others.

another note is that i use system limits per user on my system. this way each user is limited to a particular number of processes, RSS and CPU time.

Machine Specifications [was Re: Desktop Guerrilla ...]

Anonymous's picture

Can you provide a little more infoon the system limits per user? How is this done? What utilities should I study to enable this type of control? I'm aware of disk quotas, but can you provide a few utility names/tips for the others, processes, RSS, CPU time?

Thanks!

Machine Specifications [was Re: Desktop Guerrilla ...]

Anonymous's picture

system limits are configured in limits.conf. just make sure that you /etc/pam.d/system-auth has the pam_limits.so session module loaded.

Machine Specifications [was Re: Desktop Guerrilla ...]

Anonymous's picture

From real world experience I can tell you that the bottleneck you are most likely to hit is memory. I run a similar setup with about 200 clients connected to it, the server is a dual zeon 1.4 ghz machine which is not that much processor but the machine does have 4 GIG of ram and if I could put in more I would.

Numbers, numbers, numbers ...

Anonymous's picture

Nonetheless, it would be really interesting to get some numbers.
I'm considering a similar solution for a small CyberCafe (10 - 20 stations), but small here also means extremely cash strapped. So any information on how "fat" such a server actually needs to be (and thus how expensive) would be most appreciated.

Anyway, thanks for the article.

Blaze

Re: Numbers, numbers, numbers ...

Anonymous's picture

Although not the same setup as this, the article at http://linux.dbw.org/articles/linux_nt_what_the_tests_prove.html might give you some ideas on how to come up with the answer your self.

Re: Numbers, numbers, numbers ...

Anonymous's picture

> http://linux.dbw.org/articles/linux_nt_what_the_tests_prove.html

Seems unreachable at the moment but I'll try again. Thanks anyway!

Blaze

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