I have borg experience and I think Kubernetes is great. Before borg, I would basically never touch production -- I would let someone else handle all that because it was always a pain. When I left Google, I had to start releasing software (because every other developer is also in that "let someone else handle it" mindset), and Kubernetes removed a lot of the pain. Write a manifest. Change the version. Apply. Your new shit is running. If it crashes, traffic is still directed to the working replicas. Everyone on my team can release their code to any environment with a single click. Nobody has ever ssh'd to production. It just works.

I do understand people's complaints, however.

Setting up "the rest" of the system involves making a lot of decisions. Observability requires application support, and you have to set up the infrastructure yourself. People generally aren't willing to do that, and so are upset when their favorite application doesn't work their favorite observability stack. (I remember being upset that my traces didn't propagate from Envoy to Grafana, because Envoy uses the Zipkin propagation protocol and Grafana uses Jaeger. However, Grafana is open source and I just added that feature. Took about 15 minutes and they released it a few days later, so... the option is available to people that demand perfection.)

Auth is another issue that has been punted on. Maybe your cloud provider has something. Maybe you bought something. Maybe the app you want to run supports OIDC. To me, the dream of the container world is that applications don't have to focus on these things -- there is just persistent authentication intrinsic to the environment, and your app can collect signals and make a decision if absolutely necessary. But that's not the way it worked out -- BeyondCorp style authentication proxies lost to OIDC. So if you write an application, your team will be spending the first month wiring that in, and the second month documenting all the quirks with Okta, Auth0, Google, Github, Gitlab, Bitbucket, and whatever other OIDC upstreams exist. Big disaster. (I wrote https://github.com/jrockway/jsso2 and so this isn't a problem for me personally. I can run any service I want in my Kubernetes cluster, and authenticate to it with my FaceID on my phone, or a touch of my Yubikey on my desktop. Applications that want my identity can read the signed header with extra information and verify it against a public key. But, self-hosting auth is not a moneymaking business, so OIDC is here to stay, wasting thousands of hours of software engineering time a day.)

Ingress is the worst of Kubernetes' APIs. My customers run into Ingress problems every day, because we use gRPC and keeping HTTP/2 streams intact from client to backend is not something it handles well. I have completely written it off -- it is underspecified to the point of causing harm, and I'm shocked when I hear about people using it in production. I just use Envoy and have an xDS layer to integrate with Kubernetes, and it does exactly what it should do, and no more. (I would like some DNS IaC though.)

Many things associated with Kubernetes are imperfect, like Gitops. A lot of people have trouble with the stack that pushes software to production, and there should be some sort of standard here. (I use ShipIt, a Go program to edit manifests https://github.com/pachyderm/version-bump, and ArgoCD, and am very happy. But it was real engineering work to set that up, and releasing new versions of in-house code is a big problem that there should be a simple solution to.)

Most of these things are not problems brought about by Kubernetes, of course. If you just have a Linux box, you still have to configure auth and observability. But also, your website goes down when the power supply in the computer dies. So I think Kubernetes is an improvement.

The thing that will kill Kubernetes, though, is Helm. I'm out of time to write this comment but I promise a thorough analysis and rant in the future ;)