# Mastering kubectl: The Guide to Kubernetes CLI Commands Whether you’re just stepping into Kubernetes or you're managing large-scale production clusters, `kubectl` is your essential Swiss Army knife. It’s the command-line tool used to interact with your Kubernetes cluster, allowing you to deploy apps, inspect resources, troubleshoot issues, and automate workflows. In this comprehensive guide, we’ll walk through `kubectl` command, grouped by purpose, with clear explanations of what each one does. --- ## 1\. Cluster Configuration and Context Management These commands help you connect to, configure, and switch between Kubernetes clusters. * `kubectl version` Shows the version of `kubectl` and the connected Kubernetes API server. * `kubectl config view` Displays the kubeconfig file details (clusters, contexts, users). * `kubectl config use-context ` Switches the current context to a different cluster. * `kubectl config get-contexts` Lists all available contexts in your kubeconfig. * `kubectl config current-context` Prints the name of the current context. * `kubectl cluster-info` Displays addresses of the Kubernetes control plane and services. * `kubectl config set-context ` Sets a named context in your kubeconfig. --- ## 2\. Listing and Describing Resources Used for inspecting the current state of your cluster’s resources. * `kubectl get ` Lists one or more resources (e.g., `pods`, `services`, `deployments`). * `kubectl get -o wide` Adds more detail to the output (IP, node name, etc.). * `kubectl get -A` Shows resources across all namespaces. * `kubectl get all` Lists all standard resources (pods, services, deployments, etc.) in the current namespace. * `kubectl describe ` Shows detailed information about a resource, including events and configuration. * `kubectl explain ` Displays the API documentation for the resource type and fields. * `kubectl get events` Lists cluster events in chronological order. * `kubectl get componentstatuses` *(deprecated)* Shows the health of cluster components (controller manager, scheduler, etc.). --- ## 3\. Creating, Applying, and Deleting Resources For managing resource lifecycles from YAML or JSON files. * `kubectl create -f .yaml` Creates resources defined in a manifest file. * `kubectl apply -f .yaml` Creates or updates resources declaratively. * `kubectl delete -f .yaml` Deletes resources defined in the file. * `kubectl replace -f .yaml` Replaces the live resource with a new one from a file. * `kubectl create deployment --image=` Imperatively creates a deployment. * `kubectl delete ` Deletes a specific resource by name. * `kubectl delete --all` Deletes all resources of a type in the current namespace. --- ## 4\. Editing and Patching Resources For quick changes to live resources. * `kubectl edit ` Opens the resource definition in your editor for inline editing. * `kubectl patch -p ''` Applies a strategic merge patch to a resource. --- ## 5\. Working with Pods Manage and troubleshoot pods with these commands. * `kubectl get pods` Lists pods in the current namespace. * `kubectl logs ` Displays logs from a pod's main container. * `kubectl logs -c ` Shows logs from a specific container in the pod. * `kubectl exec -- ` Runs a command inside the pod (e.g., `kubectl exec pod-name -- ls /`). * `kubectl exec -it -- bash` Opens an interactive terminal session inside the container. * `kubectl port-forward 8080:80` Forwards a local port to a port on the pod. * `kubectl cp : ` Copies files from a pod to the local machine or vice versa. * `kubectl delete pod ` Deletes a specific pod. * `kubectl delete pod --all` Deletes all pods in the current namespace. --- ## 6\. Deployments and Rollouts Commands for managing application rollouts. * `kubectl rollout status deployment/` Monitors the rollout status of a deployment. * `kubectl rollout history deployment/` Shows the history of a deployment. * `kubectl rollout undo deployment/` Rolls back to the previous deployment. * `kubectl rollout restart deployment/` Triggers a new rollout by restarting the deployment. * `kubectl scale deployment --replicas=` Changes the number of pod replicas in a deployment. --- ## 7\. Services and Exposing Pods Use these to expose pods and create services. * `kubectl expose pod --port=80 --target-port=8080` Exposes a pod as a service. * `kubectl expose deployment --port=80 --type=NodePort` Exposes a deployment through a service. --- ## 8\. Namespaces Commands for managing namespaces. * `kubectl get namespaces` Lists all namespaces. * `kubectl create namespace ` Creates a new namespace. * `kubectl delete namespace ` Deletes the specified namespace. * `kubectl get pods --namespace ` Lists pods in a specific namespace. --- ## 9\. Labels and Annotations Used to organize and identify Kubernetes resources. * `kubectl label key=value` Adds or updates a label on a resource. * `kubectl annotate key=value` Adds or updates an annotation. --- ## 10\. Resource Usage Check CPU and memory consumption. * `kubectl top pod` Shows CPU and memory usage of pods. * `kubectl top node` Shows CPU and memory usage of nodes. *(Requires metrics server to be installed.)* --- ## 11\. Access Control and Security (RBAC) Useful for debugging permissions and managing roles. * `kubectl auth can-i ` Checks whether the current user is allowed to perform an action. * `kubectl describe role ` Describes a Role's permissions. * `kubectl describe clusterrole ` Describes a ClusterRole's permissions. * `kubectl get roles` / `kubectl get clusterroles` Lists roles and cluster-wide roles. --- ## 12\. Output Customization and Sorting Get more detailed or structured output. * `kubectl get -o yaml` Outputs the resource definition in YAML format. * `kubectl get -o json` Outputs the resource definition in JSON format. * `kubectl get --sort-by=.`[`metadata.name`](http://metadata.name) Sorts the resource list by a field. * `kubectl get -l key=value` Filters by label selector. --- `kubectl` is powerful because it abstracts Kubernetes operations into a unified CLI. From basic pod management to advanced rollout strategies and RBAC validation, mastering `kubectl` is essential for efficient Kubernetes operations. As Kubernetes evolves, keep an eye on updates and new flags, but this foundation will always serve you well.