--- title: "Arun (@Arun944) | Hashnode" description: "Devops Engineer. Read the latest articles by Arun on Hashnode." url: "https://hashnode.com/@Arun944" --- @Arun944 # Arun @Arun944 · Bangalore · Joined May 2023 Devops Engineer ### [CKA: Kubernetes Network Policy](https://arun944.hashnode.dev/cka-kubernetes-network-policy?utm_source=hashnode&utm_medium=feed) Introduction By default, In k8s all pods can communicate to others across all namespaces and we can restrict or control that using network policy. Network Policy (netpol) is a namespace-level component. Network policy can be applied to pod or namespa... 4 min read · [arun944.hashnode.dev](https://arun944.hashnode.dev/cka-kubernetes-network-policy?utm_source=hashnode&utm_medium=feed) [Aug 3, 2023](https://hashnode.com/posts/cka-kubernetes-network-policy/64cb06e5b6c50037a1cb541e) ### [CKA: Kubernetes Authentication Practical Guide](https://arun944.hashnode.dev/cka-kubernetes-authentication-practical-guide?utm_source=hashnode&utm_medium=feed) In this article, We will learn the k8s authentication mechanism using X509 Certificate. Authentication is the process of validating the user by k8s API-Server. In k8s, Users can be authenticated by the below strategy. X509 Certificate Bearer token... 2 min read · [arun944.hashnode.dev](https://arun944.hashnode.dev/cka-kubernetes-authentication-practical-guide?utm_source=hashnode&utm_medium=feed) [Jul 15, 2023](https://hashnode.com/posts/cka-kubernetes-authentication-practical-guide/64b24489df010cbe690cce11) ### [CKA: Kubernetes Multi Cluster Maintenance](https://arun944.hashnode.dev/cka-kubernetes-multi-cluster-maintenance?utm_source=hashnode&utm_medium=feed) Cluster Maintenance is required for the below scenarios: OS Upgrade for worker nodes. Reboot required for VM's due to hardware change. Pod Eviction Time: The controller manager will watch the replicas of the deployment or pod. If the node is do... 5 min read · [arun944.hashnode.dev](https://arun944.hashnode.dev/cka-kubernetes-multi-cluster-maintenance?utm_source=hashnode&utm_medium=feed) [Jul 8, 2023](https://hashnode.com/posts/cka-kubernetes-multi-cluster-maintenance/64a92fbdfb2bfcedd4049aef) ### [Linux: System Resource Commands](https://arun944.hashnode.dev/linux-system-resource-commands-5e7bc4bb9ae4?utm_source=hashnode&utm_medium=feed) In this article, We will discuss the most useful Linux system resource commands with real-time examples. Important Commands: df du free systemctl list-unit-files service ps kill top htop hostname ifconfig last w tee df The df command ... 5 min read · [arun944.hashnode.dev](https://arun944.hashnode.dev/linux-system-resource-commands-5e7bc4bb9ae4?utm_source=hashnode&utm_medium=feed) [Jun 3, 2023](https://hashnode.com/posts/linux-system-resource-commands-5e7bc4bb9ae4/647b6c80842ce90bbada511d) ### [Linux: Crontab Guide](https://arun944.hashnode.dev/linux-crontab-guide-bbeda7e3faa?utm_source=hashnode&utm_medium=feed) Crontab is a Linux utility that allows you to schedule commands or scripts to run automatically at specific times or intervals. It is a powerful tool that can be used for a variety of tasks, such as backing up data, sending email notifications, and r... 3 min read · [arun944.hashnode.dev](https://arun944.hashnode.dev/linux-crontab-guide-bbeda7e3faa?utm_source=hashnode&utm_medium=feed) [Jun 3, 2023](https://hashnode.com/posts/linux-crontab-guide-bbeda7e3faa/647b6abc3fd8e41ab177c979)