chinaguy
Posts: 43
Joined: Sun May 10, 2015 5:27 am
Location: Shanghai

SOLVED PiServer in a School not finding 25 * RP3B+

Thu Jul 18, 2019 10:56 am

I have built a new computer room in a School with 26 RP3B+, a laptop running PiServer and here is the PROBLEM I think the SCHOOL LOCAL AREA NETWORK!

I used these instructions https://www.raspberrypi.org/blog/piserver/ but they appear to be out of date and no mention of how to Netwotk Boot the RP3B+, can the webpage be updated?

I can see 3 RP3B(MAC Address) in the Add Clients Window but none of the 20 RP3B+ I setup on the network.

So how do I configure the PiServer to PiggyBack onto the School Network, I am using a CISCO 48port managed switch connect to the school network to pick up the internet connection. I have permission from the School Principal to twist the Network Managers Arm to get this fixed but need some instructions to give the technical boys in the broomcupboard.


The Cisco can be replaced with a couple of "dumb switch" if required, a basic 16 port domestic unit.
Last edited by chinaguy on Tue Jul 23, 2019 8:48 am, edited 1 time in total.
My other computer is a VIC20.

incognitum
Posts: 307
Joined: Tue Oct 30, 2018 3:34 pm

Re: PiServer in a School not finding 25 * RP3B+

Thu Jul 18, 2019 11:07 am

I am using a CISCO
Cisco by default enables the Spanning-Tree-Protocol.
This means that after a network link goes up, it first spends +/- 30 seconds testing for network loops, before it moves to forwarding state which finally allows normal network traffic to pass.
Problem is that the Pi gives up network booting before that time is over.

Ask your network admin to enable portfast on the switch ports connecting end-user devices such as Pi. This allows traffic through straight away, while still testing for network loops.
(If you have more than one cable going from the Ethernet switch to other Ethernet switches, do NOT enable portfast on those network ports connecting switches).

I can see 3 RP3B(MAC Address)
Are those connected to Ethernet switch ports with different settings?
All do are in the same VLAN as Piserver?

ejolson
Posts: 3407
Joined: Tue Mar 18, 2014 11:47 am

Re: PiServer in a School not finding 25 * RP3B+

Thu Jul 18, 2019 2:14 pm

chinaguy wrote:
Thu Jul 18, 2019 10:56 am
I have built a new computer room in a School with 26 RP3B+, a laptop running PiServer and here is the PROBLEM I think the SCHOOL LOCAL AREA NETWORK!
Do you accidentally have multiple DHCP servers on the network?

Alternatively, use a tiny SD card on each machine to load the kernel and an initial RAM disk and then pivot root to the network under full control of how long to wait and how to setup the network. This is how PiNet works to avoid exactly the problem you have. The end result is the same--25 Pi computers running entirely from the network.

If you are worried about keeping the kernels up-to-date, use the kernel on the SD card to chain load the correct one from the network. Otherwise, pin the kernel using the package manager and don't change it until between semesters.

incognitum
Posts: 307
Joined: Tue Oct 30, 2018 3:34 pm

Re: PiServer in a School not finding 25 * RP3B+

Thu Jul 18, 2019 2:26 pm

ejolson wrote:
Thu Jul 18, 2019 2:14 pm
Do you accidentally have multiple DHCP servers on the network?
The TS mentions that Piserver is not able to detect the Pi at all.
That part should work regardless if there are other DHCP servers present on the network.

(When adding new Pi to Piserver it detects them by simply listening for DHCP discover requests on the network coming from Pi MAC addresses.
So no actual network boot is performed during detection.
If detection fails it means no DHCP requests are received, so switch is not letting through the packets from the Pi to Piserver.
Network boot is enabled by default on Pi 3+, so it should always be sending those DHCP packets if no SD card present)

chinaguy
Posts: 43
Joined: Sun May 10, 2015 5:27 am
Location: Shanghai

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Tue Jul 23, 2019 8:59 am

I connected a "Dumb" 16 port switch to the network and got 15 RP3B+ showing in Add Client Window and can login PiServer from the connected Pis. Our network manager did not want to start "Hacking" the network so they gave my a simple 48port switch that had been in the back of the cupboard.

Not sure what the network issue we had but using "Dumb" switches seems to be the best solution, maybe this should be made clear in the How to Build instructions.

Can't wait to try a 25*RP4 on the network, the principal has promised to buy 25 RP4 as soon as the premium price drops here in Shanghai!
My other computer is a VIC20.

ejolson
Posts: 3407
Joined: Tue Mar 18, 2014 11:47 am

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Tue Jul 23, 2019 5:25 pm

chinaguy wrote:
Tue Jul 23, 2019 8:59 am
I connected a "Dumb" 16 port switch to the network and got 15 RP3B+ showing in Add Client Window and can login PiServer from the connected Pis. Our network manager did not want to start "Hacking" the network so they gave my a simple 48port switch that had been in the back of the cupboard.

Not sure what the network issue we had but using "Dumb" switches seems to be the best solution, maybe this should be made clear in the How to Build instructions.

Can't wait to try a 25*RP4 on the network, the principal has promised to buy 25 RP4 as soon as the premium price drops here in Shanghai!
Thanks for reporting back. Congratulations on solving the problems with PiServer.

Some new Pi 4B computers sound like a good plan moving forward. Since the 48-port switch you are now using was found in the back of the closet, it may not support gigabit Ethernet. While limiting speeds to 100 Mbit does not make much difference for the Pi 3, the Pi 4 can definitely benefit from a gigabit switch. If you don't already have one, I would recommend including a suitable gigabit switch as part of the Pi 4 upgrade.

andrum99
Posts: 772
Joined: Fri Jul 20, 2012 2:41 pm

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Thu Jul 25, 2019 10:57 pm

ejolson wrote:
Tue Jul 23, 2019 5:25 pm
If you don't already have one, I would recommend including a suitable gigabit switch as part of the Pi 4 upgrade.

But only if you actually need the faster speed. Also bear in mind that the Pi 4 does not yet support network boot. Support for network boot is planned soon though.

incognitum
Posts: 307
Joined: Tue Oct 30, 2018 3:34 pm

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Fri Jul 26, 2019 11:25 am

andrum99 wrote:
Thu Jul 25, 2019 10:57 pm
Also bear in mind that the Pi 4 does not yet support network boot. Support for network boot is planned soon though.
Do hope the new code takes issues like this in mind...

STP (which is enabled by default on Cisco switches) would not be a problem if the bootcode simply tried network boot long enough, and did not give up so easily.
PXE compliant gear tries for a minute (specification requires 4 DHCP requests with 4, 8, 16 and 32 second timeouts in between).

andrum99
Posts: 772
Joined: Fri Jul 20, 2012 2:41 pm

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Fri Jul 26, 2019 8:50 pm

incognitum wrote:
Fri Jul 26, 2019 11:25 am
andrum99 wrote:
Thu Jul 25, 2019 10:57 pm
Also bear in mind that the Pi 4 does not yet support network boot. Support for network boot is planned soon though.
Do hope the new code takes issues like this in mind...

STP (which is enabled by default on Cisco switches) would not be a problem if the bootcode simply tried network boot long enough, and did not give up so easily.
PXE compliant gear tries for a minute (specification requires 4 DHCP requests with 4, 8, 16 and 32 second timeouts in between).

I'm sure there are lots of rough edges that will be smoothed off with the new EEPROM-based network boot.

The problem we have here regarding PXE is that some people, including some at Raspberry Pi, call the Pi network boot PXE, when it is not PXE. I certainly think that particular part of the PXE spec would be a good one to follow. (It's called binary exponential backoff).

chinaguy
Posts: 43
Joined: Sun May 10, 2015 5:27 am
Location: Shanghai

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Thu Aug 01, 2019 10:12 am

I will be back in the classroom in 3 weeks and will be using the new PiServer so can someone make the setup instructions simple. For every teacher with my skill set with computers there are 99 who haven't got a clue about Computer Science, electronics, circuits, resistors or even tying knots in string.

For the majority of teachers they require two things from technology to use it in the classroom.

1.Take it out of the Box
2.Turn it On

Anything more forget it, it will never be used!
My other computer is a VIC20.

ejolson
Posts: 3407
Joined: Tue Mar 18, 2014 11:47 am

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Fri Aug 02, 2019 1:11 pm

chinaguy wrote:
Thu Aug 01, 2019 10:12 am
1.Take it out of the Box
2.Turn it On

Anything more forget it, it will never be used!
If a teacher doesn't have a clue about English, should that teacher teach English? If a teacher doesn't have a clue about mathematics, should that teacher teach mathematics? Why should teaching about computers be any different?

Until the students who have been taught computers grow up to become teachers, there are teacher training courses available for the Pi. Though not available in all locations, even where available, some teachers may have trouble learning computers well enough to teach about them. I suspect this is because some teachers are not actually very good learners. Thus, it would be a significant act of kindness for those teachers who know to help those who don't.

incognitum
Posts: 307
Joined: Tue Oct 30, 2018 3:34 pm

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Fri Aug 02, 2019 4:32 pm

ejolson wrote:
Fri Aug 02, 2019 1:11 pm
If a teacher doesn't have a clue about English, should that teacher teach English?
OTOH setting up Piserver is not something the average teacher is expected to teach...

Apart from the Cisco switch problem (don't have any quick solution for that).
Is there anything else in the Piserver setup procedure that you had problems with, or found hard to understand, and that should be improved?

chinaguy
Posts: 43
Joined: Sun May 10, 2015 5:27 am
Location: Shanghai

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Tue Aug 06, 2019 5:36 am

incognitum wrote: Is there anything else in the Piserver setup procedure that you had problems with, or found hard to understand, and that should be improved?
Everything basically, you have lost 99.9% of teachers by using MAC address.

Having some video tutorials that go through every fine detail of setting up a PiServer. If you think taking a PC with Windows7/10 installed and then attempting to install Debian onto the system is easy for the average person then you need to think again! Any Documentation needs to have pictures of what you see exactly on screen as any differences will confuse people building the network.

I am having the same conversation with Synology about making their NAS drives more school setup friendly for student's/staff to use in a BYOD environment.

Maybe you can get together with the Computer At Schools organization and run some weekend training on building a PiServer/Raspberry Pi Network from scratch. Then setting up User Accounts and Shared Folders as in a Monkey See Monkey Do type environment.

and some simple instructions on how to install a Network Printer would be nice and useful.

Having just got my hands on a RP4 4GB, I can see that replacing Windows PCs is a real possibility at considerably saving in costs for software and server hardware.
My other computer is a VIC20.

incognitum
Posts: 307
Joined: Tue Oct 30, 2018 3:34 pm

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Tue Aug 06, 2019 1:18 pm

chinaguy wrote:
Tue Aug 06, 2019 5:36 am
I am having the same conversation with Synology about making their NAS drives more school setup friendly for student's/staff to use in a BYOD environment.
Are Synology NAS devices popular in schools?

Technically, it is also possible to run Debian/piserver on those...
(Provided it is one of the more advanced models with Intel CPU/Virtual Machine Manager, and not an entry level model).
So seeing if it could be made easier to use those (e.g. offering a ready made .ovf VM image to import), could perhaps also be considered.

chinaguy
Posts: 43
Joined: Sun May 10, 2015 5:27 am
Location: Shanghai

Re: SOLVED PiServer in a School not finding 25 * RP3B+

Thu Aug 08, 2019 3:06 am

incognitum wrote:Are Synology NAS devices popular in schools?
Synology/QNAP NAS drives are very popular in schools, mostly run in a Department. The Music and Arts Department tend to run cross platform Windows/Apple computers so sharing resources and files across this type of setup is easy with a NAS. You just have to beat a Static IP address out of the network manager.

The school I have just set a NAS drive up in has no server access for students to save their work but they have internet access from the school s wifi. The Synology NAS can allows the setup of a managed storage area for students(USERNAME/PASSWORD) and a shared resource folder for Handouts/Documents, it also has a HandIn folder for staff to collect work off students. The NAS drives offer RAID 1 backed up onto a portable Hard drive once a week to safeguard IGCSE/IB project work.

So students bring in their own laptops, access the school wifi and then have connect to the internet, NAS and Printers.
My other computer is a VIC20.

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