Kubernetes Pod Pause Container

(The invisible glue holding a Pod together)

If you SSH into a worker node and run docker ps (or crictl ps), you will see many containers you didn’t create named pause.

What is a Pod really? We say a Pod is “one or more containers sharing a network.” But how do they share it? If Container A dies and restarts, it gets a new ID. How does it keep the same IP address?

The Solution: The Pause Container

1. When you schedule a Pod, Kubernetes starts a tiny, empty container called the Pause Container first.
2. This container reserves the Network Namespace (IP Address) and keeps it “open.”
3. Your actual app (e.g., Nginx) joins this namespace.
4. If Nginx crashes and restarts, the Pause container stays alive, holding onto the IP address.
5. The new Nginx joins the same Pause container, keeping the same IP.

💡 Summary: The Pause container is the “parent” that holds the network resources so the “children” (your apps) can die and restart without losing their network identity.