Application Development Myths

Most application development best practices were formed in a world of virtual machines and long-running processes. Kubernetes fundamentally changes those runtime guarantees—applications can restart anytime, lose local state, and run behind multiple layers of abstraction. Many production issues on Kubernetes are not caused by bad code, but by assumptions that no longer hold true. These application development myths highlight where traditional thinking breaks when applications are deployed on Kubernetes. Understanding these myths is essential to building resilient, cloud-native applications.

📄️ Myth: Applications Don’t Need Readiness or Liveness Probes

A team deployed a microservice without readiness or liveness probes. In production, Pods started receiving traffic before fully initializing, causing immediate 500 errors. One Pod even hung during startup, but Kubernetes didn’t restart it because there was no liveness probe.

📄️ Myth: Kubernetes Supports In-Place Application Upgrades

In traditional server- or VM-based environments, upgrading an application usually meant updating binaries or packages on the same machine and restarting the process. The application instance remained the same; only its version changed.