The declarative model is the core idea. Rather than issuing commands to start and stop processes, you describe what should be true — three replicas of this service, this much memory, this rollout strategy — and a control loop reconciles the cluster toward that description. Failures become self-healing rather than incidents requiring intervention.
The cost is operational complexity that is frequently underestimated. Kubernetes introduces its own networking, storage, permission and scheduling models, each of which needs to be understood before an outage rather than during one. For a handful of services, a managed container platform delivers most of the benefit at a fraction of the operational load. Adopting it because it is standard, rather than because a specific constraint demands it, is a common and expensive mistake.
Codazz builds this in production — Kubernetes & Docker.