303 lines
6.9 KiB
Markdown
Executable File
303 lines
6.9 KiB
Markdown
Executable File
Below is an enhanced version of your Kubernetes Command Reference. This revision further refines the structure, improves consistency, and adds a few extra sections for clarity and ease of use.
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---
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# Kubernetes Command Reference
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This guide provides a concise reference for common `kubectl` commands used to manage Kubernetes clusters. Whether you’re managing nodes, namespaces, pods, deployments, or autoscaling, the examples below will help you perform everyday tasks with confidence.
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---
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## Table of Contents
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- [Kubernetes Command Reference](#kubernetes-command-reference)
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- [Table of Contents](#table-of-contents)
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- [General Commands](#general-commands)
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- [Node Management](#node-management)
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- [Listing Nodes](#listing-nodes)
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- [Labeling Nodes](#labeling-nodes)
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- [Node Maintenance (Cordon/Drain)](#node-maintenance-cordondrain)
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- [Namespace Management](#namespace-management)
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- [Pod Management](#pod-management)
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- [Listing Pods](#listing-pods)
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- [Running a Pod](#running-a-pod)
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- [Deleting a Pod](#deleting-a-pod)
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- [API Resources \& Documentation](#api-resources--documentation)
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- [Logs \& Pod Information](#logs--pod-information)
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- [Applying YAML Files](#applying-yaml-files)
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- [Viewing Cluster Resources](#viewing-cluster-resources)
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- [ReplicaSet \& Deployment Management](#replicaset--deployment-management)
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- [Scaling and Rollouts](#scaling-and-rollouts)
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- [Autoscaling](#autoscaling)
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- [Port Forwarding](#port-forwarding)
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- [Additional Information](#additional-information)
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---
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## General Commands
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- **List API Resources**
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Display all available API resources along with their short names:
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```bash
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kubectl api-resources
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```
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---
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## Node Management
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### Listing Nodes
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- **Show All Nodes**
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```bash
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kubectl get nodes
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```
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### Labeling Nodes
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- **Set a Custom Label on a Node**
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```bash
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kubectl label node <node-name> kubernetes.io/<label-key>=<label-value>
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```
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> **Note:** Replace `<node-name>`, `<label-key>`, and `<label-value>` with your desired values.
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### Node Maintenance (Cordon/Drain)
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- **Cordon a Node**
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Prevent new pods from being scheduled on the node.
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```bash
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kubectl cordon <node-name>
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```
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- **Uncordon a Node**
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Mark the node as schedulable again.
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```bash
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kubectl uncordon <node-name>
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```
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- **Drain a Node**
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Evict all pods from the node (excluding those managed by DaemonSets).
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```bash
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kubectl drain <node-name> --ignore-daemonsets --delete-local-data
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```
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> **Warning:** Draining a node will evict running pods. Ensure that you plan this action to avoid service disruption.
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---
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## Namespace Management
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- **List All Namespaces**
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```bash
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kubectl get namespaces
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# Or the shorthand:
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kubectl get ns
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```
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- **Create a New Namespace**
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```bash
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kubectl create namespace <namespace-name>
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```
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---
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## Pod Management
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### Listing Pods
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- **List Pods in the Default Namespace**
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```bash
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kubectl get pods
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```
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- **List Pods with Detailed Information (Wide Output)**
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```bash
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kubectl get pods -o wide
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```
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- **List Pods in a Specific Namespace**
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```bash
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kubectl get pods -o wide -n <namespace-name>
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```
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### Running a Pod
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> **Note:** The `kubectl run` command is best suited for running single pods. For more complex deployments, consider using YAML manifests.
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- **Basic Example:**
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```bash
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kubectl run <pod-name> --image=<image-name> --port=<port-number> -n <namespace-name>
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```
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- **Advanced Example with Multiple Options:**
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```bash
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kubectl run mypod --image=nginx --port=80 -n mynamespace \
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--env="ENV_VAR_NAME=VALUE" --command -- nginx -g "daemon off;" \
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--restart=Always --dry-run=client \
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--labels="app=myapp,env=prod" \
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--limits=cpu=100m,memory=256Mi --requests=cpu=50m,memory=128Mi
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```
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**Common Options Explained:**
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- `--image`: Container image to use.
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- `--port`: Port exposed by the container.
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- `-n` or `--namespace`: Namespace in which to run the pod.
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- `--env`: Set environment variables.
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- `--command`: Treat the following arguments as the command to run.
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- `--restart`: Pod restart policy (`Always`, `OnFailure`, or `Never`).
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- `--labels`: Assign labels to the pod.
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- `--dry-run`: Validate the command without creating the pod.
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- `--limits` and `--requests`: Define resource limits and requests for the container.
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### Deleting a Pod
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- **Delete a Pod in a Specific Namespace**
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```bash
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kubectl delete pod <pod-name> -n <namespace-name>
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```
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---
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## API Resources & Documentation
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- **Get Detailed Documentation for an API Resource**
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```bash
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kubectl explain <api-resource-name>
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```
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*Example:*
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```bash
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kubectl explain pod
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```
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---
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## Logs & Pod Information
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- **Stream Logs for a Running Pod**
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```bash
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kubectl logs -f -n <namespace-name> <pod-name>
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```
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- **Get Detailed Information About a Pod**
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```bash
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kubectl describe pod <pod-name> -n <namespace-name>
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```
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---
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## Applying YAML Files
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- **Apply a Configuration from a YAML File**
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Apply a YAML configuration to a specific namespace:
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```bash
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kubectl apply -f <yaml-file> -n <namespace-name>
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```
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---
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## Viewing Cluster Resources
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- **Display All Resources in a Namespace**
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```bash
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kubectl get all -n <namespace-name>
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```
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- **Display ReplicaSets, Pods, and Deployments in a Specific Namespace**
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```bash
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kubectl get rs,pods,deployments -n <namespace-name>
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```
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---
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## ReplicaSet & Deployment Management
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### Scaling and Rollouts
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- **Scale a ReplicaSet**
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```bash
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kubectl scale rs <replicaset-name> --replicas=<count> -n <namespace-name>
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```
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- **View Rollout History of a Deployment**
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```bash
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kubectl rollout history deployment <deployment-name> -n <namespace-name>
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```
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- **View Details of a Specific Revision**
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```bash
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kubectl rollout history deployment <deployment-name> -n <namespace-name> --revision=<number>
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```
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- **Roll Back a Deployment to a Specific Revision**
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```bash
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kubectl rollout undo deployment <deployment-name> -n <namespace-name> --to-revision=<number>
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```
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### Autoscaling
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- **Autoscale a Deployment**
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Automatically scale a deployment based on CPU utilization:
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```bash
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kubectl autoscale deployment <deployment-name> -n <namespace-name> --cpu-percent=<target-cpu-percentage> --min=<min-pods> --max=<max-pods>
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```
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- **View Horizontal Pod Autoscalers (HPA)**
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```bash
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kubectl get hpa -n <namespace-name>
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```
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---
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## Port Forwarding
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Sometimes you need to access a service or pod directly from your local machine. Use the following command to forward a port:
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```bash
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kubectl port-forward -n <namespace-name> svc/<service-name> <local-port>:<target-port>
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```
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> **Example:** Forward local port 8080 to port 80 of the service named `my-service` in the `mynamespace` namespace:
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>
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> ```bash
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> kubectl port-forward -n mynamespace svc/my-service 8080:80
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> ```
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---
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## Additional Information
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- **Static Manifest Files**
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Any YAML files placed in `/etc/kubernetes/manifests/` are automatically loaded when the kubelet starts (for example, after a server reboot).
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