Tasks

Step-by-step instructions for performing operations with Kubernetes.

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Use Port Forwarding to Access Applications in a Cluster

This page shows how to use kubectl port-forward to connect to a Redis server running in a Kubernetes cluster. This type of connection can be useful for database debugging.

Before you begin

To check the version, enter kubectl version.

Creating a pod to run a Redis server

  1. Create a pod:

    kubectl create -f https://k8s.io/docs/tasks/access-application-cluster/redis-master.yaml
    

    The output of a successful command verifies that the pod was created:

     pod "redis-master" created
    
  2. Check to see whether the pod is running and ready:

    kubectl get pods
    

    When the pod is ready, the output displays a STATUS of Running:

     NAME           READY     STATUS    RESTARTS   AGE
     redis-master   2/2       Running   0          41s
    
  3. Verify that the Redis server is running in the pod and listening on port 6379:

    kubectl get pods redis-master --template='{{(index (index .spec.containers 0).ports 0).containerPort}}{{"\n"}}'
    

    The output displays the port:

     6379
    

Forward a local port to a port on the pod

  1. Forward port 6379 on the local workstation to port 6379 of redis-master pod:

    kubectl port-forward redis-master 6379:6379
    

    The output is similar to this:

     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
    
  2. Start the Redis command line interface:

    redis-cli
    
  3. At the Redis command line prompt, enter the ping command:

    127.0.0.1:6379>ping
    

    A successful ping request returns PONG.

Discussion

Connections made to local port 6379 are forwarded to port 6379 of the pod that is running the Redis server. With this connection in place you can use your local workstation to debug the database that is running in the pod.

Warning: Due to known limitations, port forward today only works for TCP protocol. The support to UDP protocol is being tracked in issue 47862.

What’s next

Learn more about kubectl port-forward.

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