seem
Posts: 1
Joined: Tue Dec 12, 2017 1:09 pm

Student folders located on server that are password protected (PiNet?)

Sun Dec 31, 2017 8:16 am

Hello everyone,

This coming February my students and I will be installing 2 solar powered computer labs in 2 Cambodian public schools. Each lab will have 20 RPI3 student computers, and the server computer will be an ODROID HC-1 http://www.hardkernel.com/main/products ... 0229074080. One of the schools has 100 students using the lab, the other will have about 300 students using the lab (not all at the same time).

As part of the requirements for the project, the computers need to be running FreeCAD as well as a locally produced english-learning program that requires the capability to watch videos in the browser. For these 2 requirements, the RPis need to have the openGL enabled as well as the ability to play videos in the browser using the video card on the RPi (Chromium/omxplayer).

I would love to use PiNet, but I don't think the current versions of Raspbian that PiNet uses enables both openGL and video playback in the browser using the video card.

What I am thinking of doing is having an easy way of creating a folder on the network for each student, so that they can store their personal files there. On the student side they would be able to access the folder with a username and/or password. Then if there was a way that the RPi could be restored to a desired fresh system state every time it reboots, I won't have to worry about the SD card on the RPi getting full or corrupted. Would SAMBA work in this case? Is there anyway of doing this easily?

Your help is greatly appreciated!

ejolson
Posts: 1572
Joined: Tue Mar 18, 2014 11:47 am

Re: Student folders located on server that are password protected (PiNet?)

Sun Dec 31, 2017 10:29 pm

seem wrote:
Sun Dec 31, 2017 8:16 am
This coming February my students and I will be installing 2 solar powered computer labs in 2 Cambodian public schools. Each lab will have 20 RPI3 student computers, and the server computer will be an ODROID HC-1 http://www.hardkernel.com/main/products ... 0229074080. One of the schools has 100 students using the lab, the other will have about 300 students using the lab (not all at the same time).

As part of the requirements for the project, the computers need to be running FreeCAD as well as a locally produced english-learning program that requires the capability to watch videos in the browser. For these 2 requirements, the RPis need to have the openGL enabled as well as the ability to play videos in the browser using the video card on the RPi (Chromium/omxplayer).

I would love to use PiNet, but I don't think the current versions of Raspbian that PiNet uses enables both openGL and video playback in the browser using the video card.

What I am thinking of doing is having an easy way of creating a folder on the network for each student, so that they can store their personal files there. On the student side they would be able to access the folder with a username and/or password. Then if there was a way that the RPi could be restored to a desired fresh system state every time it reboots, I won't have to worry about the SD card on the RPi getting full or corrupted. Would SAMBA work in this case? Is there anyway of doing this easily?
The hardware configuration is interesting, especially the choice of a low-power ARM based server to host the shared file system. It is good that it has 1GB Ethernet. Have you found suitably low-powered monitors for the Pi video displays? What are you using for the monitors?

I would definitely recommend PiNet or a PiNet-like system instead of maintaining 40 separate installations of Raspbian on 40 different SD cards. In my opinion, the main reasons not to use PiNet are if you are teaching the students to install and configure the operating system themselves or if you want them to use the Pi's at home disconnected from the school server. In particular, if you can get OpenGL and omxplayer working from an SD card, then this software should also work in a networked configuration. Having said this, SAMBA is pretty good to use for home directories and slightly lighter weight than sshfs, which I think is used by PiNet. With SAMBA make sure to enable "Unix Extensions" on the server side; otherwise, strange file-locking issues may arise with certain software.

A PiNet-like approach would mount the root file system read-only with a writable overlay. I think PiNet currently uses a shared network block device for the read-only root file system and separate network block devices for the writable overlays, though someone else here may help clarify that. Mounting a squashfs read only over NFS also works for the root file system. For the writable overlay, a RAM file system would be easier, but while this works great on 64-bit x86 systems, it does not work so well on Pi's due to the already limited RAM available. One could alternatively store the writable overlay locally on each Pi's SD card instead of using a separate network block device. This would reduce network traffic to the server, which may be important in your case.

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