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Let's Build a 28-Core Raspberry Pi Cluster

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

#41

Post by ikaruswill »

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…

I actually have had a cluster of Raspberry Pi 1Bs before this current cluster. Though the specs are very much similar to a Zero W, the performance wasn't great.

I agree that it would cost much less, but I would also get much less utility out of it. At this point, the cluster is doing quite a lot, even the site itself is hosted on it.

My point here is that having room for future utility at not much additional cost, would be best.

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

#42

Post by ikaruswill »

gchamonlive wrote: post #33
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

Thanks for reading! It's probably worth implementing it in the cloud using the free credits if hardware is prohibitively expensive, at least for the purposes of learning.

If you do intend to self-host some services in the longer term, the cost of running it on the cloud will catch up with the hardware cost in no time at all.

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

#43

Post by tra3 »

ArchD wrote: post #40

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…

The use case is tinkering. I think it’s pretty sweet to be able to build a super low cost cluster like this. Play with docker, k8s etc.

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

#44

Post by grep_it »

ArchD wrote: post #40

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…

I think Jeff Geerling answers this question succinctly in this video https://youtu.be/kgVz4-SEhbE?t=307 (starting at the 5min mark).

TL;DW - It's fun and you gain the added skills of managing bare metal with physical IO limitations.

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

#46

Post by rwallace »

ArchD wrote: post #40

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…

> Or a learning tool to make computer science & networking concepts concrete and tangible?

That seems like a perfectly good use case to me?

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

#47

Post by ikaruswill »

ArchD wrote: post #40

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…

The initial point was to build it just because, there was no real reason behind building it. But at this point, I've found quite a lot of use cases for it, specifically hosting web services for family and friends. In the process though, I've learnt to work under extreme resource/budget constraints and that alone has been invaluable imo.

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

#48

Post by ikaruswill »

justinclift wrote: post #39
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?

Thanks for the tip. I did consider Ebay, but at that point, I figured it was more trouble than it's worth if I bought them used. Ebay doesn't exactly have the best reputation.

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

#49

Post by ikaruswill »

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…

I used Ansible for the cluster in the article, PXE boot seems great but the learning curve is steep enough for me to put it off for the moment.

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

#50

Post by johntash »

pengaru wrote: post #20
daneel_w wrote: post #4

Neat setup. An alternative would perhaps be a Pine64 Clusterboard with 7 SOPINE modules: https://store.pine64.org/product/clusterboard-with-7-sopine-...

I cannot recommend doing business with pine64, their customer service is nonexistent. If you cancel your order, or need to get ahold of someone @ sales@pine64.org for any exception, in my experience you may as well shout at the nearest wall. - Someone out $165 spent on a cancelled pinephone order, no phone and no refund, complete radio silence.

> - Someone out $165 spent on a cancelled pinephone order, no phone and no refund, complete radio silence.

Hopefully you've asked your bank/creditcard to reverse the charge?

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