Good day Linux Gurus!!

I work at a spa as a maintenance guy and man has it been an adventure! I had a huge post where I asked for help some time back and got a ton of great advice and assistance.

What I wish to ask about now is the following (and I'll try my best to keep it short and organized!):

How to set up thin clients to connect via Ethernet LAN to a central server running x64 Debian Stretch.

Here is the dream:

No wireless connectivity of any kind.

Lenovo x3100 M5 with 32gb ram, 256gb SSD, 3x mechanical storage/backup drives running Debian Stretch x64 with KDE (I've got this already and KDE was the only desktop environment I could get the rest of the team to use).

Connected to:

Linux based wired router (that I would like to build myself - don't have it yet)

Which will be connected directly to and through managed switches depending on location in the building:

13 Raspberry Pis with the smallest possible OS that will only display ONE graphical application - which is a remote desktop. I.e. (I think anyway) a display adapter like xorg, no window manager, just the remote desktop. I would like to stick with rdesktop if possible for two reasons: 1. Because I will have to use it to interface with one piece of cloud based software that I can't seem to find any kind of opensource or even paid replacement for. (Yet..) 2. I can plug printers/scanners/card readers into them and forward all of that to the server so they'll work as though each thin client where it's own stand alone PC (and look the same with the full desktop environment). I would like for these things to automatically power on (probably a cron job here) at a certain time, connect to the server and automatically log in and be ready to roll, then log out and power off automatically at a certain time.

The dream would to launch rdesktop with this string of things:
rdesktop -u client# -p password# -f -x l -P -r (sound going to clients, stuff attached to client going to server) ###.###.###.###:####

And

18 Raspberry Pis with the smallest possible OS like the others, but they will only display a media player for music (all the digital music and licenses where purchased years ago) and connect via a HAT to speakers in the rooms they're in.

I've drawn up an illustration of what this will look like-ish (sorry for my shaky hand. I moved a ton of really heavy stuff right before sitting down to do this post).

http://funkyimg.com/i/2EK2G.jpeg

What I have right now (for testing purposes):
1x FriendlyArm A64
1x Raspberry Pi 3 B
2x Raspberry Pi W (worthless since I don't have an Ethernet dongle for them)

What I've got clearance to order once I've got a plan (funds are available now):
Raspberry Pi 3 B+'s and all the fixings.
Managed switches.
Tons of Ethernet cable.
Parts for a wired router.

What I've tried:
1. KRFB/KRDC
2. XRDP/rdesktop (and with many different shell scripts)
I installed xorg and every dependency I could find that it might need.

With KRFB and KRDC I've been able to get the screen to load, but it simply won't connect no matter what I do. With XRDP/rdesktop I can't get it to load at all. Trouble shot my way through more logs than I can count and just can't seem to get it right.

Any and all suggestions, advice, instructions would be greatly appreciated as always.

I'll note what I have to stick with (CEO's decision):
1. Raspberry Pi for thin clients
2. No wireless of any kind.
3. KDE

What I would like to stick with if possible, but I'll deal with it if I can't:
1. rdesktop (for forwarding printers, scanners, credit card readers, etc.. plugged into the clients to the server)
2. Debian (most stable thing I've tried yet – plus I've got the most practice with it)

Attached Thumbnails

 

As far as I know the Pi does not have any Wake on LAN capability so the only way to automatically turn them on is via a smart outlet or ethernet powered relay switch.

While the model 3s have higher power USB capability the bus is still shared with the ethernet port so I would prefer to use printers/scanners that are wired ethernet versus USB. You might need a powered hub depending on what other stuff requires USB i.e credit card reader, touch screen etc.

The following link might provide some ideas. Although it is uses Ubuntu as the server which is based upon debian so not a real big learning curve.
http://rpitc.blogspot.co.uk/

I found some hardware a while back that attached to the bottom of the pi via the GPIO pins. Which was cool as I would have been able to use it with just about any case with a little drilling. I remember reading that entire article and playing with it a bit. It was a promising project! However, I lacked the techy prowess at the time to make good use of it. As in the newest post I made, I decided to stick to something I could handle and just used rdesktop.

Thanks for the article though! At a later time, the inspiration I drew from it gave me an idea for a Linux from Scratch project. No idea how much later of a time that will be though..

I read some where that the next version of Pi is capable of power over ethernet (POE) so by controlling power to the POE switches or power injectors you can automatically power on all the Pis at the same time and a cron job could be used for shutdown.

That's awesome! I've not been able to keep up with the Jones' lately. Last thing I saw was the unveiling of the 3B+. Got one. Powered it on once. Now it's covered in dust..

POE would be pimp. And you're right, it could then be shutdown with cron. The server waking them all up the next morning would be killer too.

It is actually an add on board.

https://www.pcmag.com/news/363308/ra...r-ethernet-hat

That, is killer. And so low profile!!