On-call problems are mostly just a result of Kubernetes' "cattle not pets" brainrot ideology where people throw local simulate-ability out the window because the Rube-Goldberg web of pods and operators and cluster state gets too complex to simulate locally or keep in your head (esp. if code is located in 50+ microservice repos).

Machines (esp. Virtual Machines) are ultimately predictable and crashes don't "just randomly happen". But it's what this entire "enterprise cloud" culture has brought in, the idea that it's impossible to simulate all possible failure conditions of a cluster locally and therefore we shouldn't even try doing it. Maybe that's true at Google scale, but most companies are simply not, not, not Google-scale.

As a counter-example, I recently built a simple "cloud storage" system with a minimal Linux ISO: everything is stripped down to the absolute minimum to just boot, start a minimal S3 server and pull (encrypted and signed) update commands from an SQL "control plane" database. The entire userspace is ~50k lines of Rust (minus 10k init system) and I can simulate the entire VM locally and play with the "cluster" of VMs locally. The ISO is ~20 megabytes large and I can simulate entire datacenters "burning down", virtually, locally, before it happens for real. I can simulate everything: network failures, disk failures, slowdowns, latency, try getting Fable to hack it, etc.

But in the kubernetes "enterprise" world, I can't do any of this. First I need 10.000 values.yaml files, 10 add-ons for logging and metrics (because pushing metrics to some collection endpoint over HTTP is clearly PhD level complexity) and on top you need a service mesh to restrict random containers talking to each other because nobody knows anymore what services can talk to which other services. The results are constant outages because of misconfigurations and someone having to be on-call at all time.

Needing on-call at all (except for maybe security alerts, but those are usually not part of DevOps) is the result of this Google-influenced "crashes just happen" nonsense where "manager" culture is preferred over results (aka uptime).