Kubernetes Port Forward Command (2024)

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.

Skills Graph

%%%%{init: {'theme':'neutral'}}%%%%flowchart RL kubernetes(("`Kubernetes`")) -.-> kubernetes/TroubleshootingandDebuggingCommandsGroup(["`Troubleshooting and Debugging Commands`"]) kubernetes(("`Kubernetes`")) -.-> kubernetes/BasicCommandsGroup(["`Basic Commands`"]) kubernetes(("`Kubernetes`")) -.-> kubernetes/AdvancedCommandsGroup(["`Advanced Commands`"]) kubernetes/TroubleshootingandDebuggingCommandsGroup -.-> kubernetes/port_forward("`Port-Forward`") kubernetes/BasicCommandsGroup -.-> kubernetes/create("`Create`") kubernetes/BasicCommandsGroup -.-> kubernetes/expose("`Expose`") kubernetes/AdvancedCommandsGroup -.-> kubernetes/apply("`Apply`") subgraph Lab Skills kubernetes/port_forward -.-> lab-18494{{"`Kubernetes Port Forward Command`"}} kubernetes/create -.-> lab-18494{{"`Kubernetes Port Forward Command`"}} kubernetes/expose -.-> lab-18494{{"`Kubernetes Port Forward Command`"}} kubernetes/apply -.-> lab-18494{{"`Kubernetes Port Forward Command`"}} end

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

2. Wait for the pod to become ready:

   kubectl wait --for=condition=Ready pod -l app=nginx

3. Use the kubectl port-forward command to forward a local port to the pod:

   kubectl port-forward < pod_name > 19000:80

   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.

4. 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

   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.

2. 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: v1kind: Podmetadata: name: nginx-busyboxspec: containers: - name: nginx image: nginx - name: busybox image: busybox command: - sleep - "3600"EOF

2. Wait for the pod to become ready:

   kubectl wait --for=condition=Ready pod nginx

3. Use the kubectl port-forward command to forward a local port to the Nginx container:

   kubectl port-forward nginx-busybox 19001:80

4. 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

2. Use the kubectl port-forward command to forward a local port to the service:

   kubectl port-forward service/nginx 20000:80

3. 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.