https://DevOpsCloud.io -- Cloud Monk Losang Jinpa, Ph.D., MCSE/MCT, GitOps DevOps Engineer

kubernetes-cli provides the kubectl command-line tool that allows users to interact with Kubernetes clusters. Kubectl enables developers and administrators to manage containerized applications, deploy services, and monitor cluster resources directly from the command line.

https://formulae.brew.sh/formula/kubernetes-cli

• Definition: The Kubernetes Command-Line Interface (CLI), commonly known as `kubectl`, is a command-line tool used to interact with Kubernetes clusters. It allows users to deploy applications, inspect and manage cluster resources, and view logs.
• Function: Provides a powerful interface for managing Kubernetes clusters, enabling the execution of commands against Kubernetes clusters to perform a variety of tasks, including deploying applications, managing resources, and troubleshooting issues.
• Components:

   * '''kubectl Executable''': The main command-line tool used to interact with Kubernetes clusters.
   * '''Configuration Files''': Typically stored in `~/.kube/config`, these files contain information about cluster endpoints, authentication methods, and context settings.

• Features:

   * '''Resource Management''': Create, update, delete, and get information about resources in the cluster.
   * '''Namespace Support''': Manage resources within specific namespaces for better organization and isolation.
   * '''Label and Selector Queries''': Use labels and selectors to filter and manage resources.
   * '''Rolling Updates and Rollbacks''': Perform rolling updates and rollbacks for deployments.
   * '''Logs and Debugging''': Retrieve logs, describe resources, and troubleshoot issues in the cluster.
   * '''Extensions''': Supports custom plugins and extensions to enhance functionality.

• Usage: Essential for Kubernetes administrators and developers to manage and interact with Kubernetes clusters efficiently.

• Setting up `kubectl` with a configuration file:

   ```bash
   kubectl config set-cluster my-cluster --server=https://my-cluster.example.com --certificate-authority=ca.crt
   kubectl config set-credentials my-user --client-certificate=admin.crt --client-key=admin.key
   kubectl config set-context my-context --cluster=my-cluster --namespace=default --user=my-user
   kubectl config use-context my-context
   ```

• Deploying an application using a YAML configuration file:

   ```bash
   kubectl apply -f deployment.yaml
   ```

• Getting information about pods in a namespace:

   ```bash
   kubectl get pods -n my-namespace
   ```

• Describing a specific pod:

   ```bash
   kubectl describe pod my-pod
   ```

• Retrieving logs from a pod:

   ```bash
   kubectl logs my-pod
   ```

• Executing a command in a running pod:

   ```bash
   kubectl exec -it my-pod -- /bin/bash
   ```

• Scaling a deployment:

   ```bash
   kubectl scale deployment my-deployment --replicas=3
   ```

• Performing a rolling update:

   ```bash
   kubectl set image deployment/my-deployment my-container=my-image:v2
   ```

• kubernetes-cli (kubectl): A command-line tool for interacting with Kubernetes clusters. It enables users to deploy applications, manage cluster resources, view logs, and troubleshoot issues. With features like resource management, namespace support, and rolling updates, `kubectl` is an essential tool for Kubernetes administrators and developers.