Helm-Based Operator Tutorial Part 1 - Build the Operator (Chart, CRD, watches.yaml)
A Helm-based operator wraps a Helm chart as a Kubernetes operator without you writing any Go code. The Operator SDK ships a generic reconciler that watches a CR, maps its `.spec` to Helm values, and runs `helm install` / …
Owner References and Garbage Collection in Kubernetes Operators
A complete guide to owner references and Kubernetes garbage collection for operators: the contract between an owner and its dependents, the difference between `SetControllerReference` and `SetOwnerReference`, three …
Install Operator-SDK on Linux: Complete Setup Guide (Go, kubectl, Helm 4, kind, ttl.sh registry)
A complete step-by-step guide to installing Operator-SDK on Linux (Ubuntu, RHEL, Fedora, Debian), including the prerequisite toolchain (Go 1.22+, kubectl, container runtime, Helm 4 CLI, kind), the three Operator-SDK …
Kubernetes Operator vs Controller vs CRD: What's the Difference?
A Custom Resource Definition (CRD) is the API contract, a Controller is the reconciler that watches and acts on it, and an Operator is the combination of a CRD plus a controller plus domain-specific knowledge about a …
What is a Kubernetes Operator?
A Kubernetes Operator is a custom controller paired with a Custom Resource Definition (CRD) that automates the day-2 operations of a complex application - install, upgrade, backup, failover, scaling - by continuously …
Git & GitHub Tutorial for Beginners (with examples)
Free, hands-on Git and GitHub tutorial that walks you from `git init` to advanced rebase, stash, and history rewriting in 14 chapters. 60+ examples tested on Linux, macOS, and Windows.
Ansible Tutorial for Beginners [RHCE EX294 Exam]
Free, hands-on Ansible tutorial for beginners that takes you from zero to RHCE EX294. Lab setup, playbooks, roles, vaults, AWS provisioning - 27 lessons across 8 chapters, every example tested on RHEL 8+.
Kubernetes SecurityContext Explained with Practical YAML Examples
Learn Kubernetes SecurityContext with practical YAML examples for runAsUser, fsGroup, Linux capabilities, privileged containers, readOnlyRootFilesystem, and Kubernetes security hardening best practices.
Kubernetes Sidecar Pattern Explained with Real Examples (Multi-Container Pod YAML)
Learn how Kubernetes sidecar containers work with practical multi-container Pod examples. Understand shared volumes, shared network namespaces, logging sidecars, YAML configuration, and common real-world sidecar use …
Parcel Management System Architecture (APIs, Database, Event-Driven Design)
Learn how to design a scalable parcel management system using APIs, database schema, event-driven architecture, queues, and cloud-native technologies like Kafka and Kubernetes.
Golang JWT Authentication (Gin + REST API + Middleware Examples)
Learn how to implement JWT authentication in Golang using Gin and PostgreSQL. This step-by-step guide covers user signup, login, JWT token generation, middleware validation, REST API usage, and common errors for building …
What Developers Should Know About the Hardware Their Code Runs On
Learn why understanding hardware fundamentals like CPU, memory, storage, and printed circuit boards is essential for developers to build high-performance, scalable, and reliable applications in modern computing …
How to Delete a Repository in GitHub (Step-by-Step Guide)
Learn how to delete a repository in GitHub using both the web interface and command line. This guide explains how to remove GitHub repositories, delete local Git repositories, remove files and folders, and safely clean …
How to Unstage Files in Git (Without Losing Changes)
Learn how to unstage files in Git using git restore, git reset, and git rm commands. This guide explains how to remove files from the staging area, undo git add, unstage all files, and keep changes safely without losing …
Git Switch vs Checkout Explained (How to Switch Branch in Git)
Learn how to use git switch to change branches in Git. This guide explains git switch vs git checkout, switching branches, creating new branches, commands, examples, and fixing common errors.
Git Show Command Explained (View Commit Details, Diff & Files with Examples)
Learn how to use git show to view commit details, file changes, and diffs. This guide explains git show command usage, examples, viewing specific commits, files, tags, and comparing git show vs git diff and git log.
Git Stash Explained (Save Local Changes Without Commit + Examples)
Learn how to use git stash to save local changes without committing. This guide covers git stash commands, examples, applying and popping stashes, listing stashes, fixing errors like no local changes to save, and …
Git Tag Explained (Create, Push, Delete & Best Practices)
Learn how to use git tag to create, list, push, delete, and manage tags in Git. This guide covers tagging concepts, version tagging, commands, examples, and best practices for release management.
How to Squash Commits in Git (Combine, Clean History, Before & After Push)
Learn how to squash commits in Git using rebase and merge. This guide covers combining commits, squashing last N commits, squashing all commits in a branch, before and after push workflows, fixing errors, and recovering …
Git Set Upstream Explained (origin vs upstream + Fix Errors + Examples)
Learn how to set upstream in Git with practical examples, fix common errors like no upstream branch, and understand origin vs upstream. This guide covers git push --set-upstream, git branch upstream setup, fork …
Git rm Command Explained (Remove Files, Undo & --cached Examples)
Learn how to use the git rm command with practical examples. This guide covers removing files and folders, git rm vs rm differences, git rm --cached usage, undoing git rm, and handling real-world scenarios safely without …
How to Rename File or Directory in Git (git mv Explained)
Learn how to rename a file or directory in Git using git mv and other methods. This guide covers renaming files, folders, and directories with practical examples, preserving history, handling case sensitivity issues, and …
Git Restore Explained with Examples (Files, Staged, Undo Changes)
Learn how to use git restore command with practical examples. Understand how to restore files, undo changes, unstage files using git restore --staged, and compare git restore vs reset vs checkout. Includes syntax, use …
Git Reset Explained (Soft vs Mixed vs Hard) with Examples
Learn Git reset with practical examples including soft, mixed, and hard reset. Understand the differences, use cases, and how git reset affects the working directory, staging area, and commit history. Fix common errors …
[SOLVED] Unable to Delete Docker Image (Image Has Dependent Child Images)
Learn how to fix the Docker error "unable to delete image (cannot be forced) - image has dependent child images". This guide explains why the error occurs, how Docker image dependencies work, and step-by-step solutions …
Docker Build Without Cache (docker build --no-cache Explained)
Learn how to build Docker images without using cache using the docker build --no-cache option. This guide explains when to disable cache, how Docker layer caching works, and provides practical examples for DevOps …
How to Find and Remove Unused Docker Containers (5 Safe Methods + Best Practices)
Learn how to find and remove unused Docker containers using safe and practical methods. Compare docker rm, docker container prune, filters, and automation techniques with real-world examples for production and …
Run Multiple Commands in Docker Compose (4 Methods + Examples & Best Practices)
Learn how to run multiple commands in Docker Compose using 4 practical methods including &&, multiline scripts, shell scripts, and Supervisor. Understand execution order, failure handling, and best practices with …
Stop All Docker Containers (4 Easy Methods + Examples & Best Practices)
Learn how to stop all Docker containers using multiple methods including docker stop, docker kill, and filtered commands. Understand differences, safe practices, and real-world use cases with examples.
Docker .dockerignore Explained (Best Practices + Examples to Optimize Builds)
Learn how to use .dockerignore to optimize Docker builds by excluding unnecessary files. Improve build speed, reduce image size, and follow best practices with real-world examples.