There's no restart command for a Pod. You updated a config value your app reads only at startup, so you typed kubectl restart pod, and got an unknown command error. A Pod, remember, is just one running copy of your app.

Kubernetes doesn't restart a Pod. It replaces it. A Deployment, the controller that manages your Pods, starts from three old Pods, swaps one for a new Pod, then another, until all three are new. By default, the remaining Pods keep serving traffic throughout.

Run kubectl rollout restart, then deployment slash your-app. You're not touching a Pod. You're telling the Deployment to swap its Pods for fresh ones, gradually. The new Pods read your updated startup data, and the app stays up while it happens.

To refresh your Pods, ask the Deployment with rollout restart. Kubernetes doesn't restart your app. It replaces it.