Couldn't you get nearly the same behavior using some basic Ansible playbooks? My impression was that the killer feature of k8s was scaling, automatic failover, etc., although to be fair it's been several years since I last looked into it.

Think of kubernetes as a cluster operating system. Instead of dealing with vms, you deal with your applications directly, without worrying about where they're running. It gives you a unified view and ability to manage a distributed system at the level of the application components.

Ansible can't give you anything like that. Even if you use Ansible to automate something like network setup, the commands and modules you use will be different between e.g. cloud providers. Kubernetes give you a consistent abstraction layer that's almost unchanged across providers, with the exception of annotations that are needed in some cases for integration with certain provider services.

For me k8s kinda extends what you can do with ansible.

For example, if you use just kubelet (the main daemon) without the api, drop some static yaml files (ala unit files) under /etc/kubernetes it will be something like systemd is. No big deal so far, but using the kubernetes api (just another daemon) it allows you to run the all the things anywhere.

I mean, you terminate one computer, k8s will figure out that the program should be running and it will be started in another computer. (Including moving detaching/attaching the block device from/into computers, this kind of things)

There is no much secret.

For me it really feels like an (well designed/integrated) API on top of standard Linux technology (ipvs, netfilter, mount, process mgmt, virtual ip, etc) via yaml running your stuff in 1..N computers but you manage it as one big computer :)

EDIT: added more context within "()"

I go in and out of development and ops and devops. 20 years.

To me as a developer heroku is the gold standard.

Docket-compose makes sense.

Kubernes and helm is a giant soul crushing wtf On getting anything done.

Now I’ll get it figure it out. Angular + exhaust+ typescript was a similar experience after I took a break from front end for a few years. A few months of pain, then it starts clicking.

but this just seems insane for a basic web app. So many different tools needed to get it going. Tutorials all have many steps that don’t apply, or use other odd pieces swapped in.

Many tutorials are unfortunately bad, they actually got worse over time.

Oooold presentations (think 2016 and older) tended to talk more about basic building blocks and how they interacted, especially the design involving resources and their controllers working in a loop of "check requested state, check real state, do changes to implement requested state", and how those loops went up from single pods, through ReplicationControllers (now ReplicaSets), then Deployments, etc.

This is the exact problem I ran into on rxjs. Every tutorial was badly out of date. Even ones written six months earlier.

You had to become a master of figuring out the direction of where community was going and stay on bleeding edge.

Some people found this fun. I have many times enjoyed this. When I want to get a boring feature built and hand off to the jr develops so I can spend some time with my kids. It’s frustrating

The most annoying thing, to me, is that Kubernetes doesn't even move fast enough!

The old presentations? Ones that remember K8s 1.0? There's one major change (move from Replication Controller to Deployment+ReplicaSet) that doesn't invalidate ~90% of the material, because the core stuff is about how controllers work!

Yet it seems more and more common to me that people don't learn the core mechanism of kubernetes unless per chance they got there writing CRDs :|

> Couldn't you get nearly the same behavior using some basic Ansible playbooks?

No. For starters, Ansible playbooks don't allow you to dynamically deploy and redeploy a set of containers in the node that at a given moment happens to have more available computational resources such as bandwidth, nor do teu respawn a container that just happened to crash.

Arguably Ansible only implementos a single feature of Kubernetes: deploy an application. Even so, while with Ansible you need to know and check all details about the underlying platform, with Kubernetes in essence you only need to say "please run x instantes of these containers".

Ansible gets you like 80% of the value of Kubernetes, yes. But you have to allocate applications to hosts manually, your configuration is less declarative, and what do you gain?