Understanding Kubernetes: Part 33 Startup Probe

📢 If you’ve been following our Kubernetes series 2025, welcome back! For new readers, check out Part 32 Vertical Pod Autoscaler (VPA)

📖 Not a Medium member? No worries! Here’s the free link: Part 33 — Startup Probe

What is a Startup Probe in Kubernetes?

A Startup Probe in Kubernetes is a type of probe designed to determine if a container within a pod has started successfully. It is useful for applications that have long startup times or require significant initialization before they are ready to handle requests. Unlike the Liveness Probe or Readiness Probe, which are designed to check the health and readiness of a pod once it is already running, the Startup Probe helps ensure that Kubernetes doesn’t prematurely consider a container as unhealthy during the startup process.

If the startup probe fails, Kubernetes will kill and restart the pod. However, if the startup probe is successful, Kubernetes assumes that the container is running properly and will then rely on the readiness probe (if configured) to check whether the pod is ready to handle traffic.

For example:

Consider an application that needs to load a large dataset into memory at startup. This could take several minutes, and during this time, the…