https://dileepkumar.dev/ Recent content on Dileep Kumar https://dileepkumar.dev/papermod-cover.png https://dileepkumar.dev/papermod-cover.png Hugo -- gohugo.io en Wed, 16 Apr 2025 00:24:48 +0530 https://dileepkumar.dev/tools/subnet-planner/ Wed, 08 Jan 2025 16:30:00 +0530 https://dileepkumar.dev/tools/subnet-planner/ Visual subnet planning tool with interactive tree visualization https://dileepkumar.dev/tools/cidr-calculator/ Wed, 08 Jan 2025 16:30:00 +0530 https://dileepkumar.dev/tools/cidr-calculator/ Calculate IP ranges, subnet masks, and visualize network topology https://dileepkumar.dev/tools/dns-checker/ Wed, 08 Jan 2025 16:30:00 +0530 https://dileepkumar.dev/tools/dns-checker/ Look up DNS records for any domain — A, AAAA, MX, CNAME, TXT, NS, and more https://dileepkumar.dev/post/setting-up-a-local-yum-repository-on-rhel-for-offline-or-controlled-environments/ Wed, 16 Apr 2025 00:24:48 +0530 https://dileepkumar.dev/post/setting-up-a-local-yum-repository-on-rhel-for-offline-or-controlled-environments/ In environments with limited or no internet access—like secure datacenters or air-gapped systems—managing software packages can be a hassle. That’s where setting up a local YUM repository on your RHEL machine becomes incredibly handy. In this guide, I’ll walk you through the step-by-step process to set up your own local repository server for RHEL 8 and RHEL 9 using httpd (Apache) and createrepo. Let’s dive in! 🏊‍♂️ 1: Download Necessary Packages on a Machine with Internet Before we begin, you’ll need access to a machine that can connect to the internet, just once. https://dileepkumar.dev/docker-guides/ Tue, 14 Jan 2025 00:10:00 +0530 https://dileepkumar.dev/docker-guides/ 🐳 Complete Docker Learning Path Welcome to the complete Docker guide series! This collection is designed to take you from a beginner to a proficient Docker user, covering everything from core concepts to orchestration. 📚 Learning Path 🎯 Fundamentals (Start Here) Docker Images and Containers - Complete Guide Master the absolute basics: build images and run containers. Docker Volumes and Bind Mounts Learn how to persist data in your Docker applications. https://dileepkumar.dev/post/docker-commands-cheatsheet/ Tue, 14 Jan 2025 00:08:00 +0530 https://dileepkumar.dev/post/docker-commands-cheatsheet/ Introduction This cheatsheet provides a quick reference for the most common Docker commands. Getting Started # Run a test image to verify installation docker run hello-world # Display system-wide information docker info # Display Docker version information docker version Image Management # List all images docker images ls # Pull an image from a registry (Docker Hub by default) docker image pull alpine # Push an image to a registry docker image push your-username/your-image # Build an image from a Dockerfile # -t tags the image with a name docker image build -t my-app . https://dileepkumar.dev/post/docker-configuration-and-security/ Tue, 14 Jan 2025 00:07:00 +0530 https://dileepkumar.dev/post/docker-configuration-and-security/ Introduction Properly configuring Docker is essential for both security and functionality, especially in enterprise and production environments. This comprehensive guide covers critical configuration scenarios, security hardening techniques, and best practices for running Docker safely in production. We’ll explore proxy configuration, registry trust management, security scanning, resource limits, and the principle of least privilege—all essential for production-ready Docker deployments. Part 1: Configuring Docker for Corporate Networks Understanding the Proxy Challenge In corporate environments, direct internet access is often restricted. https://dileepkumar.dev/post/dockerfile-best-practices/ Tue, 14 Jan 2025 00:06:00 +0530 https://dileepkumar.dev/post/dockerfile-best-practices/ Introduction A Dockerfile is the blueprint for building Docker images. It’s a text file containing a series of instructions that Docker reads from top to bottom to assemble an image. Understanding how to write efficient, secure, and maintainable Dockerfiles is fundamental to mastering Docker. This comprehensive guide takes you from Dockerfile basics to advanced optimization techniques, covering every instruction, when to use it, and best practices for production-ready images. https://dileepkumar.dev/post/docker-content-transfer-and-data-management/ Tue, 14 Jan 2025 00:05:00 +0530 https://dileepkumar.dev/post/docker-content-transfer-and-data-management/ Introduction While volumes and bind mounts are the primary methods for persistent data in Docker, there are times when you need to quickly copy files between your host machine and a running or stopped container. This is where the docker cp command becomes invaluable. This comprehensive guide covers everything about transferring content with Docker, from basic file copying to advanced data management strategies, troubleshooting, and best practices. Why You Need docker cp Common Use Cases: https://dileepkumar.dev/post/docker-registry-setup-and-management/ Tue, 14 Jan 2025 00:04:00 +0530 https://dileepkumar.dev/post/docker-registry-setup-and-management/ Introduction While Docker Hub is excellent for public images, production environments require private registries for proprietary applications. A private Docker registry gives you complete control over your container images, their storage location, access permissions, and distribution. This comprehensive guide covers everything from running a basic local registry to implementing production-grade solutions with authentication, TLS encryption, and high availability. Why Run a Private Docker Registry? Security and Compliance: Keep proprietary code and sensitive applications off public registries Meet regulatory requirements for data sovereignty Control who can access your images with fine-grained permissions Scan images for vulnerabilities before deployment Performance and Reliability: https://dileepkumar.dev/post/docker-swarm-and-services/ Tue, 14 Jan 2025 00:03:00 +0530 https://dileepkumar.dev/post/docker-swarm-and-services/ Introduction You’ve mastered single containers with docker run and multi-container applications on a single host with Docker Compose. But what happens when your application needs to scale beyond one machine? What if you need high availability, automatic failover, and load balancing across multiple servers? This is where container orchestration comes in, and Docker Swarm is Docker’s native solution. Swarm transforms a pool of Docker hosts into a single, virtual Docker host, allowing you to deploy and manage containerized applications at scale. https://dileepkumar.dev/post/docker-compose-mastery/ Tue, 14 Jan 2025 00:02:00 +0530 https://dileepkumar.dev/post/docker-compose-mastery/ Introduction So far, we’ve dealt with single containers. But real-world applications are rarely that simple. They are often composed of multiple, interconnected services: a web server, a database, a caching layer, a message queue, and more. Managing the lifecycle, networking, and data for all these separate containers with individual docker run commands would be a nightmare. This is the problem that Docker Compose solves. It is an essential tool for defining and running multi-container Docker applications. https://dileepkumar.dev/post/docker-volumes-and-bind-mounts/ Tue, 14 Jan 2025 00:01:00 +0530 https://dileepkumar.dev/post/docker-volumes-and-bind-mounts/ Introduction A core principle of Docker is that containers should be ephemeral and stateless. This means that any data created inside a container’s writable layer is lost forever when the container is removed. While this is great for creating predictable and clean environments, it poses a significant challenge for any application that needs to save data—like databases, user uploads, or logs. To solve this, Docker provides three primary mechanisms for getting data into and out of containers: Volumes, Bind Mounts, and tmpfs mounts. https://dileepkumar.dev/post/docker-images-and-containers-complete-guide/ Tue, 14 Jan 2025 00:00:00 +0530 https://dileepkumar.dev/post/docker-images-and-containers-complete-guide/ Introduction Welcome to the world of Docker! This comprehensive guide is your first step into containerization. We will explore the absolute fundamentals: Dockerfiles, Images, and Containers. Understanding these three core components is the key to mastering Docker. By the end of this guide, you will not only have built and run your first containerized application but also grasped the “why” behind each step. We’ll build a simple Python Flask web application from scratch, package it into a portable Docker image, and run it as an isolated container on your local machine. https://dileepkumar.dev/post/kubernetes-kind-cluster-setup/ Mon, 13 Jan 2025 01:00:00 +0530 https://dileepkumar.dev/post/kubernetes-kind-cluster-setup/ Introduction Kind (Kubernetes IN Docker) is a tool for running local Kubernetes clusters using Docker containers as nodes. It’s perfect for local development, testing, and CI/CD pipelines. In this comprehensive guide, I’ll show you how to set up and use Kind for your Kubernetes development workflow. What is Kind? Kind is a tool designed to run Kubernetes clusters locally using Docker container “nodes”. Originally designed for testing Kubernetes itself, it’s now widely used for: https://dileepkumar.dev/post/kubernetes-commands-cheatsheet/ Mon, 13 Jan 2025 00:40:00 +0530 https://dileepkumar.dev/post/kubernetes-commands-cheatsheet/ Introduction This comprehensive cheatsheet covers essential kubectl commands for daily Kubernetes operations. Bookmark this for quick reference! Cluster Info kubectl version kubectl cluster-info kubectl get nodes kubectl get componentstatuses kubectl config view kubectl config current-context kubectl config use-context <context-name> Pods # List kubectl get pods kubectl get pods -o wide kubectl get pods --all-namespaces kubectl get pods -n <namespace> kubectl get pods --show-labels kubectl get pods -l app=nginx # Create kubectl run nginx --image=nginx kubectl run nginx --image=nginx --dry-run=client -o yaml > pod. https://dileepkumar.dev/post/kubernetes-health-probes/ Mon, 13 Jan 2025 00:35:00 +0530 https://dileepkumar.dev/post/kubernetes-health-probes/ Introduction Kubernetes needs to know when your applications are healthy and ready to serve traffic. Health Probes enable Kubernetes to automatically detect and recover from application failures, ensuring high availability. Understanding Health Probes The Problem Without Probes: Crashed applications continue receiving traffic Deadlocked processes never recover Slow-starting apps receive traffic too early Failed containers remain in “Running” state The Solution: Health probes provide automated health monitoring and recovery: Automatic restart of failed containers Traffic routing only to healthy pods Graceful startup for slow applications Self-healing without manual intervention Types of Probes - Complete Comparison Probe Type Purpose Action on Failure When to Use Liveness Is container alive? https://dileepkumar.dev/post/kubernetes-production-cluster-setup/ Mon, 13 Jan 2025 00:30:00 +0530 https://dileepkumar.dev/post/kubernetes-production-cluster-setup/ Introduction Setting up a production-ready Kubernetes cluster requires careful planning and configuration. This guide walks you through creating a multi-node cluster using kubeadm and containerd as the container runtime. Prerequisites Minimum Requirements: 2 GB RAM per machine 2 CPUs per machine Network connectivity between machines Unique hostname, MAC address, product_uuid Swap disabled Recommended for Production: 3+ control plane nodes (HA) 3+ worker nodes 4 GB+ RAM per node Load balancer for control plane Architecture Load Balancer (Optional for HA) ↓ Control Plane Nodes (3) ↓ Worker Nodes (3+) Step 1: Prepare All Nodes On all nodes (control plane + workers): https://dileepkumar.dev/post/kubernetes-monitoring-prometheus-grafana/ Mon, 13 Jan 2025 00:25:00 +0530 https://dileepkumar.dev/post/kubernetes-monitoring-prometheus-grafana/ Introduction Production Kubernetes clusters require robust monitoring. Prometheus collects metrics, while Grafana visualizes them, providing complete observability into your cluster’s health and performance. Architecture Kubernetes Cluster ↓ Prometheus (Metrics Collection) ↓ Grafana (Visualization) ↓ Dashboards & Alerts Installing with Helm Add Prometheus Community Helm repo: helm repo add prometheus-community https://prometheus-community.github.io/helm-charts helm repo update Install kube-prometheus-stack: helm install prometheus prometheus-community/kube-prometheus-stack \ --namespace monitoring \ --create-namespace Verify installation: kubectl get pods -n monitoring kubectl get svc -n monitoring Accessing Grafana Port forward: https://dileepkumar.dev/post/kubernetes-helm-package-manager/ Mon, 13 Jan 2025 00:20:00 +0530 https://dileepkumar.dev/post/kubernetes-helm-package-manager/ Introduction Managing multiple Kubernetes YAML files becomes complex quickly. Helm is the package manager for Kubernetes, simplifying deployment and management of applications through reusable templates called Charts. What is Helm? Helm packages Kubernetes resources into Charts - reusable, versioned, and shareable packages. Key Concepts: Chart: Package of Kubernetes resources Release: Instance of a Chart running in cluster Repository: Collection of Charts Installing Helm # macOS brew install helm # Linux curl https://raw. https://dileepkumar.dev/post/kubernetes-ingress-guide/ Mon, 13 Jan 2025 00:15:00 +0530 https://dileepkumar.dev/post/kubernetes-ingress-guide/ Introduction Exposing multiple services with LoadBalancer creates multiple cloud load balancers (expensive!). Ingress provides HTTP/HTTPS routing to multiple services using a single load balancer, with features like path-based routing, SSL termination, and virtual hosting. Understanding Kubernetes Ingress The Problem Without Ingress: Service 1 → LoadBalancer ($$$) Service 2 → LoadBalancer ($$$) Service 3 → LoadBalancer ($$$) Total: 3 load balancers, high cost! The Solution With Ingress: ┌─→ Service 1 Ingress Controller ─┼─→ Service 2 (Single LB) └─→ Service 3 Total: 1 load balancer, low cost! https://dileepkumar.dev/post/kubernetes-daemonsets-jobs/ Mon, 13 Jan 2025 00:10:00 +0530 https://dileepkumar.dev/post/kubernetes-daemonsets-jobs/ Introduction Not all workloads need to run continuously or be replicated across nodes. DaemonSets ensure one Pod per node (perfect for logging agents), while Jobs and CronJobs handle batch processing and scheduled tasks. Understanding Different Workload Types Kubernetes Workload Controllers: Controller Purpose Replicas Lifecycle Use Case Deployment Stateless apps Multiple Continuous Web servers, APIs StatefulSet Stateful apps Multiple Continuous Databases, queues DaemonSet Node services One per node Continuous Logging, monitoring Job Batch tasks Configurable Run to completion Data processing CronJob Scheduled tasks Configurable Scheduled Backups, reports Why Different Controllers? https://dileepkumar.dev/post/kubernetes-advanced-scheduling/ Mon, 13 Jan 2025 00:05:00 +0530 https://dileepkumar.dev/post/kubernetes-advanced-scheduling/ Introduction By default, Kubernetes scheduler automatically places Pods on available nodes. But what if you need more control? Perhaps you want GPU-intensive workloads on specific nodes, or need to isolate production from development workloads. Node Affinity, Taints, and Tolerations give you fine-grained control over Pod placement. Understanding Kubernetes Scheduling Default Scheduler Behavior: The Kubernetes scheduler automatically assigns Pods to nodes based on: Available resources (CPU, memory) Node conditions (ready, disk pressure, memory pressure) Pod resource requests and limits Quality of Service (QoS) class Why Advanced Scheduling? https://dileepkumar.dev/kubernetes-guides/ Mon, 13 Jan 2025 00:00:00 +0530 https://dileepkumar.dev/kubernetes-guides/ 🚀 Complete Kubernetes Learning Path Welcome to my comprehensive Kubernetes guide series! This collection covers everything from basics to production-ready deployments. Follow the guides in order for a structured learning path, or jump to specific topics as needed. 📚 Learning Path 🎯 Fundamentals (Start Here) Kubernetes Pods - Complete Guide Master the fundamental building blocks of Kubernetes Creating pods (imperative & declarative) Pod lifecycle and troubleshooting Best practices for production Kubernetes Deployments Mastery https://dileepkumar.dev/post/kubernetes-storage-mastery/ Mon, 13 Jan 2025 00:00:00 +0530 https://dileepkumar.dev/post/kubernetes-storage-mastery/ Introduction Containers are ephemeral by nature - when they restart, all data is lost. For stateful applications like databases, this is unacceptable. Kubernetes provides a robust storage abstraction through Persistent Volumes (PV), Persistent Volume Claims (PVC), and Storage Classes to solve this challenge. In this guide, I’ll show you how to implement persistent storage in Kubernetes, from basic concepts to production-ready StatefulSets. Understanding Kubernetes Storage The Problem: # Without persistent storage - data lost on restart! https://dileepkumar.dev/guides/ Mon, 13 Jan 2025 00:00:00 +0530 https://dileepkumar.dev/guides/ 📚 Complete Learning Guides Welcome to my collection of comprehensive technical guides! Each guide series is designed to take you from basics to production-ready expertise. 🚀 Available Guide Series 🐳 Docker - Complete Learning Path 9 Comprehensive Guides | Beginner to Advanced Master Docker from the ground up. This series covers everything from creating your first container to orchestration with Swarm. Topics Covered: Images, Containers, and Volumes Dockerfile Best Practices Docker Compose for multi-container apps Private Registry Management Introduction to Docker Swarm 📖 Start Docker Learning Path 🚀 Kubernetes - Complete Learning Path 13 Comprehensive Guides | Beginner to Advanced https://dileepkumar.dev/post/kubernetes-configuration-management/ Sun, 12 Jan 2025 23:45:00 +0530 https://dileepkumar.dev/post/kubernetes-configuration-management/ Introduction Hardcoding configuration values and sensitive data directly into your application code is a recipe for disaster. It makes your applications inflexible, insecure, and difficult to manage across different environments. Kubernetes provides two powerful objects to solve this problem: ConfigMaps for configuration data and Secrets for sensitive information. In this comprehensive guide, I’ll show you how to effectively manage application configuration and secrets in Kubernetes, following security best practices and production patterns. https://dileepkumar.dev/post/kubernetes-services-deep-dive/ Sun, 12 Jan 2025 23:40:00 +0530 https://dileepkumar.dev/post/kubernetes-services-deep-dive/ Introduction In Kubernetes, Pods are ephemeral - they can be created, destroyed, and replaced at any time. This creates a challenge: how do you reliably connect to your applications when Pod IP addresses constantly change? The answer is Kubernetes Services. Services provide stable networking endpoints for your Pods, enabling reliable communication both within your cluster and from external clients. In this comprehensive guide, I’ll walk you through the three main Service types - ClusterIP, NodePort, and LoadBalancer - with practical examples and production best practices. https://dileepkumar.dev/post/kubernetes-deployments-mastery/ Sun, 12 Jan 2025 23:35:00 +0530 https://dileepkumar.dev/post/kubernetes-deployments-mastery/ Introduction While Pods are the fundamental units in Kubernetes, you’ll rarely create them directly in production. Instead, you’ll use Deployments - a higher-level abstraction that provides declarative updates, scaling, and self-healing capabilities for your applications. In this comprehensive guide, I’ll walk you through everything you need to know about Kubernetes Deployments, from basic creation to advanced rollout strategies and rollback procedures. This is essential knowledge for anyone managing production Kubernetes workloads. https://dileepkumar.dev/post/kubernetes-pods-complete-guide/ Sun, 12 Jan 2025 23:30:00 +0530 https://dileepkumar.dev/post/kubernetes-pods-complete-guide/ Introduction Pods are the fundamental building blocks of Kubernetes. Understanding how to create, manage, and troubleshoot pods is essential for anyone working with Kubernetes. In this comprehensive guide, I’ll walk you through everything you need to know about Kubernetes pods, from basic creation to advanced troubleshooting techniques. Whether you’re just starting with Kubernetes or looking to deepen your understanding, this guide covers both imperative (command-line) and declarative (YAML-based) approaches to pod management. https://dileepkumar.dev/post/syncing-obsidian-notes-with-syncthing/ Fri, 29 Nov 2024 00:24:48 +0530 https://dileepkumar.dev/post/syncing-obsidian-notes-with-syncthing/ Background If you’re someone who loves taking notes, organizing your ideas, or documenting your work, you’ve probably come across Obsidian. It’s an amazing note-taking app that’s packed with features. I recently started using it and was impressed by how well it works across platforms like macOS, Windows, Android, and iOS. In Obsidian, your notes are stored in a Vault, which is essentially a folder where you can create files and organize them with subfolders. https://dileepkumar.dev/post/multi-node-cluster-kind/ Sat, 16 Dec 2023 00:24:48 +0530 https://dileepkumar.dev/post/multi-node-cluster-kind/ Background If you are like me who wants to try out new tools or test something on Kubernetes, then I have something for you. Yes, you can create a Kubernetes cluster locally using Minikube and Docker, but we’ll be limited to a single-node cluster, which might not suffice for many use cases like testing multi-node scenarios, HA configurations, or distributed applications. In this article, I’ll guide you on how you can create a multi-node local Kubernetes cluster using Kind (Kubernetes in Docker). https://dileepkumar.dev/about/ Wed, 29 Nov 2023 17:32:53 +0530 https://dileepkumar.dev/about/ Hello, I’m Dileep Kumar. I’m from Mysore, India 🇮🇳 You can learn more about my professional experience on my LinkedIn profile. I am always looking for new opportunities to collaborate with others, and I am always eager to learn new things. If you have any questions or suggestions, please do not hesitate to get in touch with me on email dileepkumarxdev@gmail.com This website is personal blog which I use to document my learning journey and share my work with the world. https://dileepkumar.dev/education/ Wed, 29 Nov 2023 17:32:53 +0530 https://dileepkumar.dev/education/ Education Bachelor of Technology Electronics and Communication Engineering Government Engineering College 2016 - 2020 Focused on electronics, communication systems, and engineering fundamentals. Verify → Certifications Associate Cloud Engineer Google Issued: December 2024 View Credential → Solutions Architect – Associate AWS Issued: March 2023 View Credential → Azure Fundamentals Microsoft Issued: May 2022 View Credential → Azure Data Fundamentals Microsoft Issued: June 2022 View Credential → Security, Compliance, and Identity Fundamentals Microsoft https://dileepkumar.dev/resume/ Wed, 29 Nov 2023 17:32:53 +0530 https://dileepkumar.dev/resume/ {a{< ppt src=“https://docs.google.com/spreadsheets/d/1QVJrXHt6AtUBFNTbk0i_213cCSfmTDb2rRQ1C_fvVIs/edit?usp=drive_link" >}}