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Let's Build a 28-Core Raspberry Pi Cluster

ikarus.sg

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Re: Let's Build a 28-Core Raspberry Pi Cluster

#31

Post by justinclift »

magicalhippo wrote: post #7

So I was toying with the idea of something similar. I'm a programmer and not a sysadmin, but I've dabbled with Docker and had a specific use-case. But so far I've not come further than this: how to deal with the host OS? Like, I don't want to log into N computers and manually run "sudo apt update" etc. I want them to run the same OS but with slightly different configurations. Network booting via PXE seems to be the b…

The "Self Hosted" list on awesome-baremetal would probably be interesting to look over for this:

https://github.com/alexellis/awesome-baremetal#self-hosted

Re: Let's Build a 28-Core Raspberry Pi Cluster

#33

Post by gchamonlive »

ikaruswill wrote: post #23

Hello, original author here. I saw a bunch of traffic from Hacker News and decided to drop by. Thanks for sharing it here! I'd be happy to answer any questions.

Hey there. Thanks for the article!

I wanted to ask you if it is worth it implementing something similar in the cloud to learn kubernetes. The hardware is prohibitively expensive on Brazil, so maybe a cluster of t2.micro on AWS running for the total amount of 750 hours could serve the learning purpose for free

Re: Let's Build a 28-Core Raspberry Pi Cluster

#35

Post by numpad0 »

sxp wrote: post #24

A slightly cheaper option would be to get a bunch of Pi Zero W devices. They're $10 + SDcards. They would rely on WiFi which might be acceptable if the use case allows having a few dozen radios chattering next to each other. If not, then a $5 Pi Zero + $5-10 ethernet adapter might work. Since the goal isn't to achieve maximum performance, the slow CPU & RAM (comparable to a 20th century desktop) might not be an issue…

Zero/Zero W at $5/$10 are promotional price, for first unit per person only. For second unit and after you have to order case kits or other high(positive) margin options.

Re: Let's Build a 28-Core Raspberry Pi Cluster

#36

Post by dehrmann »

jvilalta wrote: post #12
magicalhippo wrote: post #7

So I was toying with the idea of something similar. I'm a programmer and not a sysadmin, but I've dabbled with Docker and had a specific use-case. But so far I've not come further than this: how to deal with the host OS? Like, I don't want to log into N computers and manually run "sudo apt update" etc. I want them to run the same OS but with slightly different configurations. Network booting via PXE seems to be the b…

Ansible works great on PIs

Yeah, if you're concern is managing a lot of machines, Salt, Puppet, Ansible, or Chef are the right tool; this isn't really a Docker thing. The PXE boot idea is interesting, and you can even do that diskless.

Re: Let's Build a 28-Core Raspberry Pi Cluster

#37

Post by numpad0 »

mdoms wrote: post #5

Am I understanding that he is storing web data on the SD cards of the Pis? Is that normal? SD storage is notoriously unreliable, especially in write-heavy applications.

People who complain about SD card "reliability" is just writing to it way too often.

Longevity of NAND flash is measured in TBW(total bytes written, in terabytes) but they have 4MB or so minimum size for write access, so people easily end up writing effectively gigabytes over weeks or months thinking it's just kilobytes averaged and use up all its life in just few months to years.

You don't need "better quality SD cards", you stop issuing writes. As for why Raspbian isn't built that way so you don't have to be Linux storage experts just to run it correctly, I don't know.

Re: Let's Build a 28-Core Raspberry Pi Cluster

#39

Post by justinclift »

ikaruswill wrote: post #23

Hello, original author here. I saw a bunch of traffic from Hacker News and decided to drop by. Thanks for sharing it here! I'd be happy to answer any questions.

> An alternative was to use commercial-grade network switches with 16 ports but that was obviously was out of the question (and budget).

Ebay?

Re: Let's Build a 28-Core Raspberry Pi Cluster

#40

Post by ArchD »

What's the actual use case for rpi clusters like this? If the goal is to learn docker or k8s using a realistic setup involving multiple machines, can't it be achieved by using multiple VMs on one physical desktop instead of using the cluster? The 7-node cluster has only 7GB RAM in total, which is not too much to ask on a desktop.

I don't know what people do with rpi clusters and I'm honestly puzzled why people bother building them. If you get a beefy expensive server, I can understand -- you care about performance. If you get a single rpi to serve files & media in a home LAN it makes sense too -- low footprint, low power and low cost. But I don't know what a rpi cluster excels at. Is it just a toy? Or a learning tool to make computer science & networking concepts concrete and tangible? Or just to get a computer system on a shoestring budget, much cheaper than even a single desktop or laptop?

BTW, computer hardware in Singapore is overpriced. $140 for a switch in Singapore vs $73 for a similarly-capable switch on Amazon. https://www.amazon.com/TP-Link-Ethernet-Unmanaged-Rackmount-...

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