architecture

A design question with a clear answer at this scale, and the reasoning is what scores. The three options solve different problems and peering and Transit Gateway connect networks while PrivateLink exposes services.

Most candidates can sell serverless. The question asks you to argue against it, which needs a real understanding of the execution model rather than the marketing.

Spreading instances across availability zones is not the same as surviving an AZ failure. What makes the difference is being able to name the four coupling points that quietly re-unify a blast radius you thought you had split.

The services-and-enterprise interview staple. There is a defensible answer and it is not 'always re-platform': the decision is a function of change tolerance, deadline reality and what the workload is worth.

DNS failover is a blunt instrument with three delays stacked on top of each other: detection, propagation and client caching. Knowing their sizes tells you when DNS is the right layer at all.

Residency is not a checkbox on the primary datastore. Where bytes sit, who holds keys, and where logs, backups and analytics quietly replicate decide whether the deal signs.

Data transfer is charged in several unrelated ways and reported as one line, so the first job is decomposition. Most surprises are cross-zone chatter between services that never needed to be on different nodes.

Follow a Deployment change through the API server, controllers, scheduler and kubelet. Each handoff gives you a different place to investigate when a pod never starts.

Follow scheduling eligibility, job isolation and artifact transfer, then diagnose a queued job whose available runners cannot satisfy its requirements.

The pull model is the famous part and explains none of the operational pain. The storage engine is where Prometheus hurts in production: crash recovery, cold queries, disk death.

Agent per node, gateway per cluster, and one decision that shapes everything else: tail sampling needs every span of a trace in one place, which is why the topology has a tier that looks redundant until you need it.

The default answer is 'horizontal' because interviews reward it. The correct answer names the constraint that makes distribution expensive and knows when one big machine is the engineering choice.

A mandatory gateway can centralize limits and filtering, while applications authorize business actions. Neither a prompt nor a PII classifier guarantees that sensitive data stays private.