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Kubernetes Port Forward Command: A Comprehensive Guide

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Introduction

In this lab, you will learn how to use the Kubernetes port-forward command to forward a local port to a port on a pod. You will start with simple examples and gradually progress to more complex scenarios.

Forwarding a Local Port to a Pod

In this step, you will learn how to forward a local port to a port on a pod.

  1. Start by creating a deployment with one replica and an Nginx container: 
 kubectl create deployment nginx --image=nginx --replicas=1
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  1. Wait for the pod to become ready: 
 kubectl wait --for=condition=Ready pod -l app=nginx
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  1. Use the kubectl port-forward command to forward a local port to the pod: 
 kubectl port-forward < pod_name > 19000:80
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Replace <pod_name> with the name of the pod created in step 1, and you can get the <pod_name> with the kubectl get pod -l app=nginx command.

  1. Open a web browser and go to http://localhost:19000 to view the Nginx welcome page.

Forwarding Multiple Local Ports to a Pod

In this step, you will learn how to forward multiple local ports to a pod.

  1. Use the kubectl port-forward command to forward multiple local ports to the pod: 
 kubectl port-forward 19443:443 < pod_name > 19080:80
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Replace <pod_name> with the name of the pod created in step 1, and you can get the <pod_name> with the kubectl get pod -l app=nginx command.

  1. Open another terminal and use the ss command at the Linux command line to see if ports 19080 and 19443 are on the host.

Forwarding a Local Port to a Pod with Multiple Containers

In this step, you will learn how to forward a local port to a specific container in a pod with multiple containers.

  1. Create a pod with two containers: Nginx and BusyBox: 
 cat << EOF | kubectl apply -f - apiVersion: v1 kind: Pod metadata: name: nginx-busybox spec: containers: - name: nginx image: nginx - name: busybox image: busybox command: - sleep - "3600"  EOF
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  1. Wait for the pod to become ready: 
 kubectl wait --for=condition=Ready pod nginx
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  1. Use the kubectl port-forward command to forward a local port to the Nginx container: 
 kubectl port-forward nginx-busybox 19001:80
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  1. Open a web browser and go to http://localhost:19001 to view the Nginx welcome page.

Using Port-Forward with Kubernetes Services

In this step, you will learn how to use the kubectl port-forward command with Kubernetes services.

  1. Create a service for the Nginx deployment: 
 kubectl expose deployment nginx --port=80 --type=ClusterIP
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  1. Use the kubectl port-forward command to forward a local port to the service: 
 kubectl port-forward service/nginx 20000:80
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  1. Open a web browser and go to http://localhost:20000 to view the Nginx welcome page.

Summary

Congratulations, you have successfully completed the Kubernetes port-forward command lab! In this lab, you learned how to forward a local port to a pod, forward multiple local ports to a pod, forward a pod port to a local port, forward a local port to a specific container in a pod with multiple containers, and use the kubectl port-forward command with Kubernetes services. These skills are essential for debugging issues in a Kubernetes cluster.

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Top comments (1)

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Alex Pliutau •

Great write-up, we also have a bunch of articles on Kubernetes, check it out here - packagemain.tech