Hi all, I've been venturing for months in this amazing self-hosted hobby and for the last couple of days I'm reading and trying to understand kubernetes a bit more, I've followed this article :
that helps you set up the lightweight Kubernetes version (K3s) and use Portainer as your management dashboard, and it works flawlessly, as you guys can see I'm just using two nodes at the moment.
And I'm using "helm" to install packages and the site ArtifactHUB to get ready to use repository to add into portainer Helm section (still in beta) but works flawlessly, I've installed some packages and the apps works just as I expected, but there's seem to be a shortage of ready to use repository as it's the case with docker alone, like with Plex the only way I got plex running in K3s is with KubeSail with offers an unofficial apps section that includes plex and tons of other well known apps, but strangely enough there are labeled unofficial but still works perfect when installed, but portainer would label all apps installed from KubeSail as external.
Now I think I get the use of kubernetes, it's to have several nodes to use as recourses for your apps and also like a load balance if one node fails your services/apps can keep on running? (like raid for harddisks?)
All tough it was fun learning atleast the basic of Kubernetes with my two nodes, is it really necessary to go full blown out with only kubernetes? Or is Docker just fine for the majority of us homelad self hosted folks?
And is what I'm learning here the same in enterprise environments? Atleast the basics?
10+ years at Google as an SRE. While borg =!= k8s, I've seen my fair share of platforms come and go. The trend seems to reward shifts towards declarative automation rather than imperative orchestration models. In the programming world, you'll hear the term idempotent, similar idea. There is no substitute or wrapper that can take imperative and make it declarative without tons of work. Ansible is imperative where if something goes wrong it is easiest to nuke then try again. K8s is the culmination of various imperative-based automation systems at Google, attempts at replacing them with declarative, then try again, then finally start afresh with an open-source version of borg.
Not many companies need the scale of Google, with thousands of engineers trying to modify production with hardened interfaces that force developers to write their applications in such an opinionated way (stateful applications must use StatefulSet, dynamic configuration should go into a ConfigMap, separate your command line arguments from the command being executed from the environment variables, LoadBalancers are distinct from and are an implementation detail of Services....).
But with the good foundation that k8s provides and imposes, you set yourself up for letting the infrastructure team not care about what is running on what hardware. They can focus on doing hardware, networking, disk swapouts... Ops can focus on service uptime, readiness+liveness probers, standardized monitoring/logging, traffic routing and rollouts. Devs can focus on writing code. These standards reduce the leakage that often happens between these 3 groups.
Taking declarative to the next level, you build CICD pipelines that can take your yaml files in a github repo and automatically push them. To the next level you want to account for importing templates and standard libraries, so you look to Kustomize till you realize that it doesn't give you the building blocks you need. You then start to adopt more declarative models where the source code (both java and json/yaml config files) can be built and the artifacts of that build step are what are fed into k8s, making your github repo the source of truth. Then all production fiddling is done with PRs rather than clicking buttons in an imperative way on some UI.
The more you see automation tools, the more you realize that declarative offers a more robust interface that can be glued to other declarative systems, albiet adding yet another layer of abstraction. This complexity is often not streamlined enough for people on this subreddit, as well as for lots of people writing self-hosted apps. Helm is about as both streamlined and exhaustive as you're going to get.
I agree with many here that learning k8s is best if you're needing to learn it for your job, or you have hopes of getting into the DevOps field.
I am currently setting up my home server using Ansible and I'd say 50% of my time/energy is trying to make it as idempotent as possible. Things like ok I want my service started but I want to restart it if it changed etc.
Although the main downside with k8s is that I don't think you can do much low level/privileged stuff. Like setting up a VPN for a single container, accessing devices for monitoring etc.