I think that there are a lot of use cases of Pis for which online cloud providers might be a better option.
Where does it become a better idea to just rent a few instances in Azure/EC2/Google Cloud?
Let's Build a 28-Core Raspberry Pi Cluster
51–60 of 158 posts
Re: Let's Build a 28-Core Raspberry Pi Cluster
#52Hello, 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.
Fascinating, pardon my ignorance but I’m new to this home brew clustering thing. How is the coordination between the nodes handled for a use case like serving a wordpress blog? Or are we talking about n-1 nodes behind a load balancing master node?
Re: Let's Build a 28-Core Raspberry Pi Cluster
#53"I started noticing the performance bottlenecks started when I tried to run Wordpress on it, where a single page load of a newly installed Wordpress blog takes about 10 seconds!" 10 seconds is probably not bad for an uncached wordpress page.
10 seconds is terrible, a WordPress page should render in under 2 seconds.
Re: Let's Build a 28-Core Raspberry Pi Cluster
#54Personally I would not use pi's for this. Massive waste of money, the experience is worth it but other than that..
What would you use then?
600$ buys you a considerable amount of time in a cloud vendor. For example you can have a 1vCPU instance in Hetzner for 3€/month, which means 600$ can buy you about a year's worth of 20 instances running 24/7.
If you don't need 99.9999 availability of your cluster and are only interested in firing up the cluster from time to time then those same 600$ can buy you a few years of cluster time
Re: Let's Build a 28-Core Raspberry Pi Cluster
#55So 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…
Last time i checked ipxe was still not supported on pi boards that I think have a very convoluted boot process. Maybe someone with more time and passion than me can eventually figure it out =)
Re: Let's Build a 28-Core Raspberry Pi Cluster
#56What'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…
This could be very handy for running integration tests of cluster-management software!
Re: Let's Build a 28-Core Raspberry Pi Cluster
#57Hello, 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
If you have a PC, then just run it on VM(s) on that. That's what AWS is giving you anyway.
Here's an example: https://kubernetes.io/blog/2019/03/28/running-kubernetes-loc...
Re: Let's Build a 28-Core Raspberry Pi Cluster
#58Earlier quoted context omitted.
> 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.
Ahhh. I guess it depends on what you're looking for.
Mellanox cards and related cabling is generally still pretty good (in UK and Australia anyway).
A few years ago I obtained a few 24 port HP Procurve switches (3400cl-24G), with 10GbE (CX4 connectors) on the back.
Those worked pretty well, though turned out to be slightly too noisy for use as desktop switches. ;)
Taking a quick look on US Ebay now, something like this (US$39) might have been workable:
https://www.ebay.com/itm/HP-J9145A-ProCurve-2910al-24G-Ether...
I don't know that seller at all, but ex-enterprise HP Procurve gear should generally be pretty safe. From reputable vendors anyway. :)
For Singapore, I'm not sure. Might have needed to get something from the US shipped over. This one seems like it'd be ~US$80 including shipping, which was probably too much:
https://www.ebay.com/itm/HP-ProCurve-Switch-1800-24G-switch-...
Re: Let's Build a 28-Core Raspberry Pi Cluster
#59Am 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.
Brand SD cards are quite reliable. If you configure your SW to avoid sources of needless constant write churn (eg. like postgresql stats collector), and use good power supply, they will last years.
If you use Postgres as a single master on any storage device, you will also want to disable the slave writes, which seem to be enabled by default. If your device crashes with those enabled, Postgres may not start up again without manual intervention.
Also, use the most current version since Postgres has had a brutal number of CVEs in the past few years which are in metasploit.
Re: Let's Build a 28-Core Raspberry Pi Cluster
#60I have to admire someone who spends their first paycheck on a pi cluster: > The total damage my wallet sustained from Kraken was S$626.63 or in $449.73 USD, which was virtually all I had left for the month after subtracting expenses and education loan repayments.
All power to him.
Nobody got successful by playing it safe.