⭐ Scenario #6: Auto-Update ConfigMap Without Restarting the Pod (Using Volume Mount)

November 9, 2025

This content originally appeared on DEV Community and was authored by Latchu@DevOps

This scenario demonstrates:

ConfigMap mounted as a file
Pod picks up changes automatically without restart
Application reads updated data from the file in real time
You verify live updates

This is how apps like Nginx, Prometheus, and Spring Boot use dynamic config reloads.

Step 1 — Create a ConfigMap

Create dynamic-configmap.yaml:

apiVersion: v1
kind: ConfigMap
metadata:
  name: dynamic-config
data:
  message: "Hello from ConfigMap v1"

Apply it:

kubectl apply -f dynamic-configmap.yaml

Step 2 — Create a Pod That Mounts the ConfigMap as a File

Create pod-dynamic-config.yaml:

apiVersion: v1
kind: Pod
metadata:
  name: dynamic-config-pod
spec:
  containers:
    - name: demo-container
      image: busybox
      command: ["sh", "-c", "while true; do echo \"Message: $(cat /config/message)\"; sleep 3; done"]
      volumeMounts:
        - name: config-volume
          mountPath: /config
  volumes:
    - name: config-volume
      configMap:
        name: dynamic-config

Apply it:

kubectl apply -f pod-dynamic-config.yaml

Wait for ready:

kubectl wait --for=condition=Ready pod/dynamic-config-pod --timeout=60s

Step 3 — View Live Output From the Pod

Open logs:

kubectl logs -f dynamic-config-pod

You will see:

Message: Hello from ConfigMap v1
Message: Hello from ConfigMap v1
...

Keep this logs window open.

Step 4 — Update the ConfigMap Without Restarting the Pod

Edit the ConfigMap:

kubectl edit configmap dynamic-config

Change the value:

message: "Hello from ConfigMap v2 - UPDATED LIVE"

Save & exit.

Step 5 — Watch the Pod Update Automatically (NO Restart Needed)

Your logs will automatically switch:

Message: Hello from ConfigMap v1
Message: Hello from ConfigMap v1
Message: Hello from ConfigMap v2 - UPDATED LIVE
Message: Hello from ConfigMap v2 - UPDATED LIVE

No pod restart
No rollout
No manual intervention

WHY does this work?

Method	Auto-Update?	Reason
ConfigMap → env variables	No	Env vars are fixed at Pod startup
ConfigMap → mounted volume	Yes	Kubelet updates file symlink every ~1–2 seconds