Pete's Log: I Miss My Pi Cluster
Entry #2708, (Coding, Hacking, & CS stuff, Home Automation)(posted when I was 46 years old.)
It's been nearly a year since I retired the pi Kubernetes cluster and I miss it. I've set up some applications like FreshRSS directly on some of the pis and I don't like it as much as I liked the cluster.
The fundamental problem with the pi cluster was that it was easily perturbed into an unstable state and as best I can tell this was because I wasn't using fast enough storage on the pis hosting etcd. etcd doesn't like latency and will quickly bail on a node if it isn't storing values fast enough. And once etcd started switching up nodes, latency generally went up everywhere and the system could spend a long time moving around etcd nodes until it lucked into a state where latency was acceptable.
At least that's my novice interpretation, filtered through a year of my own memory degradation. So I'm thinking of setting up a new Kubernetes cluster. I was at Micro Center today and they had a ton of Raspberry Pi 5 gear, which was cool. But all my Pis are Pi 4s. The bit of kit that most spoke to me was the SSD hats they had for the Pi 5. And I wish they had the same thing for the Pi 4 in stock.
So if I decide to be crazy enough to recreate a home Kubernetes cluster, I see a few options:
- Buy three Pi 5s to host the etcd cluster and outfit them with SSD hats
- Buy SSD hats for three (or more) of my Pi 4s
- Buy some proper computers and run Kubernetes on those
I like option 1 because I can buy everything I need at Micro Center. But it seems excessive. Option 2 requires sourcing things online and I don't want to give any money to the obvious online place. Option 3 is the obvious option if I'm going to spend money and want this to just work. But then I lose the charming conversation starter of telling people about my home Raspberry Pi Kubernetes cluster.
Guess I'll sleep on it.