How to Access a Pod Using Its IP Address?

How to Access a Pod Using Its IP Address?

Each Pod in Kubernetes gets an internal IP within the cluster. You can find the IP using:

kubectl get pods -o wide

Example output:

NAME           READY   STATUS    IP           NODE
easy-recipes   1/1     Running   10.244.1.12  worker-node-1

Here, the Pod's IP is 10.244.1.12.

To access it:

curl http://10.244.1.12:80

This works only within the cluster because Pod IPs are assigned by Kubernetes' internal network.

Limitations of Accessing Pods via IP

1. Pods are ephemeral – If a Pod is restarted or rescheduled, its IP changes.
2. Pod IPs are not accessible externally – You can’t access Pod IPs from outside the cluster.
3. Networking policies may block access – Some clusters restrict direct Pod-to-Pod communication.

Better Ways to Access Pods

Use a Service (Recommended)

Instead of using the Pod’s IP, expose it using a Service:

kubectl expose pod easy-recipes --type=ClusterIP --port=80 --name=easy-recipes-service

Then, access it within the cluster:

curl http://easy-recipes-service:80

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Use Port Forwarding (For Debugging)

If you need direct access to a Pod from your local machine:

kubectl port-forward pod/easy-recipes 8080:80

Now, open:

http://localhost:8080

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Use a NodePort or LoadBalancer Service

If you need external access, expose the Pod using a NodePort or LoadBalancer:

kubectl expose pod easy-recipes --type=NodePort --port=80
kubectl get svc easy-recipes

Look for the NodePort and access:

http://<NODE-IP>:<NODE-PORT>

Can One Pod Access Another in Kubernetes?

Yes! One Pod can communicate with another Pod in Kubernetes, but it depends on how networking is set up. Here’s how you can achieve inter-pod communication.

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Accessing Another Pod Using Its IP (Not Recommended)

Every Pod gets an IP address assigned by Kubernetes. You can find it with:

kubectl get pods -o wide

Example output:

NAME             READY   STATUS    IP           NODE
app-pod         1/1     Running   10.244.1.12  worker-node-1
db-pod          1/1     Running   10.244.1.15  worker-node-1

You can then curl the other Pod (inside the cluster):

kubectl exec -it app-pod -- curl http://10.244.1.15:80

Limitations:

• Pod IPs change when restarted.
• Not a stable way to communicate.
• Works only inside the cluster.

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** Accessing Another Pod Using a Service (Recommended)**

A Kubernetes Service provides a stable way for Pods to communicate. Instead of using Pod IPs, we use the Service name.

Create a Deployment for an App (Example: Frontend)

kubectl create deployment frontend --image=nginx

Create a Deployment for Another App (Example: Backend)

kubectl create deployment backend --image=ram1uj/easy-recipes

Expose the Backend as a Service

kubectl expose deployment backend --port=80 --name=backend-service

This creates a ClusterIP Service, allowing internal access.

Access Backend from Frontend Pod

Now, inside the frontend pod, we can access backend-service by name:

kubectl exec -it $(kubectl get pods -l app=frontend -o jsonpath='{.items[0].metadata.name}') -- curl http://backend-service:80

Pods can now communicate using the stable service name instead of changing Pod IPs.

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Using Environment Variables for Service Discovery

When a Service is created, Kubernetes automatically adds environment variables in Pods that match the Service name.

Example:

kubectl exec -it frontend-pod -- env | grep BACKEND_SERVICE

You will see environment variables like:

BACKEND_SERVICE_SERVICE_HOST=10.96.0.10
BACKEND_SERVICE_SERVICE_PORT=80

You can use these variables in your application to connect to the backend.

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** Using DNS for Pod-to-Pod Communication**

Kubernetes has an internal DNS service that allows Pods to communicate using service names.

If a Service is called backend-service, it is reachable at:

http://backend-service.default.svc.cluster.local

You can test this inside any Pod:

kubectl exec -it frontend-pod -- curl http://backend-service.default.svc.cluster.local