connecting-to-applications-port-forward.md

PLEASE NOTE: This document applies to the HEAD of the source tree

If you are using a released version of Kubernetes, you should refer to the docs that go with that version.

The latest 1.0.x release of this document can be found [here](http://releases.k8s.io/release-1.0/docs/user-guide/connecting-to-applications-port-forward.md).

Documentation for other releases can be found at releases.k8s.io.

Connecting to applications: kubectl port-forward

kubectl port-forward forwards connections to a local port to a port on a pod. Its man page is available here. Compared to kubectl proxy, kubectl port-forward is more generic as it can forward TCP traffic while kubectl proxy can only forward HTTP traffic. This guide demonstrates how to use kubectl port-forward to connect to a Redis database, which may be useful for database debugging.

Creating a Redis master

$ kubectl create examples/redis/redis-master.yaml
pods/redis-master

wait until the Redis master pod is Running and Ready,

$ kubectl get pods
NAME           READY     STATUS    RESTARTS   AGE
redis-master   2/2       Running   0          41s

Connecting to the Redis master[a]

The Redis master is listening on port 6397, to verify this,

$ kubectl get pods redis-master -t='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
6379

then we forward the port 6379 on the local workstation to the port 6379 of pod redis-master,

$ kubectl port-forward redis-master 6379:6379
I0710 14:43:38.274550    3655 portforward.go:225] Forwarding from 127.0.0.1:6379 -> 6379
I0710 14:43:38.274797    3655 portforward.go:225] Forwarding from [::1]:6379 -> 6379

To verify the connection is successful, we run a redis-cli on the local workstation,

$ redis-cli
127.0.0.1:6379> ping
PONG

Now one can debug the database from the local workstation.