kubectl port-forward and proxy

Services and Networking / Guide 38 of 44 / Beginner

• Kubernetes1.36.4
• Cluster4 nodes
• Runtimecontainerd 2.2.6
• CNICalico v3.32.1
• TimeAbout 14 min

A forward to svc/name resolves the Service to ONE of its Pods and tunnels to that Pod for the lifetime of the connection. It does not load-balance, and if that Pod is deleted the forward dies rather than moving - which is why a forward that stops working during a rollout is expected behaviour.

This guide includes

Use this when you need to reach something in the cluster without changing how it is exposed. This matters because port-forward tunnels through the API server for you alone - it is a debugging tool, not a way to publish an application.

• forwarding a local port to a Service, and understanding that it resolves to one Pod
• forwarding to a Pod and to a Deployment, and seeing how those differ
• using kubectl proxy to reach the API server itself
• seeing plainly what port-forward is not, and what to reach for instead

Before you start

• kubectl with access to the cluster. No cluster changes are needed for the forwarding part.
• The session creates namespace ckad-fwd, a two-replica Deployment behind a ClusterIP Service, and starts and stops four forwards.

1. 1

   Something to reach

2. 2

   port-forward to a Service

3. 3

   To a Pod, and to a Deployment

4. 4

   The API itself, through a proxy

5. 5

   What port-forward is not

Official sources

• Use Port Forwarding to Access Applications in a Cluster
• Access Clusters Using the Kubernetes API
• Service - NodePort