Hi all! I'm extremally new to Kubernetes and learning a lot.. But my plan is to build a K3s cluster with selfheal (3 VM's on same host to start trying stuff out) and Rancher and Longhorn, Prometheus, Grafana and maybe lot's more when i learn more. But my question to you because I'm also new to databases. "MySQL or PostgreSQL?" I have never dealt with SQL before and it would be installed on my NAS in a docker. This is just for setup at home.

all of those things are going to put a ton of IO load on your underlying storage. LH and Prometheus are both quite IO intensive. Especially if you’re running 3 LH replicas against the same physical disk. I wouldn’t be surprised if you end up having reliability problems due to that.

I've only tried Kubernetes for a week or two so everything is brand new! I saw that you can use "metrics server" or Prometheus/Grafana in OpenLens but maybe I don't even need to think about it in Rancher?

generally you don’t take them down for upgrades… you just drop a new binary on the host and restart the service

Oh! So maybe just even a single node would work for me then.. Haha! As you can see. still learning!