Flagship #1 · PublishedLinux Internals
How Linux decides who can open a file
Tracing process credentials from task_struct to struct cred, the six-step newgrp syscall sequence, and in-memory inode resolution.
#linux#kernel#devops#security
Flagship publications
Technical deep-dives
Twelve flagship engineering stories, syndicated across Hashnode as the primary blog, Medium for reach, and this interactive reader.
Flagship #2 · PublishedSecurity & Exploitation
Your code is clean. Attackers still got a shell.
PHP2Shell and Node2Shell attack flow: request-to-shell traversal, runtime boundaries, and where defensive controls actually belong.
#security#rce#php#nodejs
Flagship #3 · PublishedCloud Networking
Port 443 is open in the security group. Why does it still time out?
NACLs versus security groups on AWS: packet path, stateful versus stateless return traffic, and ephemeral port drop rules.
#aws#networking#vpc#security
Flagship #4 · PublishedIncident Drills
I broke two servers on purpose and gave myself an hour to fix them
A production incident drill end to end: alert, decoy, root cause, fix timeline, and the undo-daemon trap.
#linux#sre#troubleshooting#incidents
Flagship #5 · PublishedLinux & Virtualization
A RHEL lab you can wreck and reset in seconds
Base image to thin qcow2 overlays to a snapshot tree, with instant cloud-init bootstrap on KVM.
#rhel#kvm#cloud-init#virtualization
Flagship #6 · PublishedRed Hat Certification
My 60-day plan from RHCSA to RHCE
A week-by-week roadmap and hands-on milestones for Linux administration and Ansible automation.
#rhcsa#rhce#ansible#certification
Flagship #7 · PublishedAnsible & RHCE
Every RHCSA task, translated to Ansible
The definitive matrix: manual command, Ansible module, collection, and idempotency verification.
#ansible#rhcsa#automation#devops
Flagship #8 · PublishedAnsible & RHCE
The no-SSH rule: automating a whole exam set with Ansible
Automating complete RHCSA topologies without manual SSH, through a revert, run and verify loop.
#ansible#rhce#ex294#automation
Flagship #9 · PublishedAnsible & RHCE
Ansible variable precedence, drawn
The 22-level precedence ladder showing which variable wins, with a worked breakdown of surprising overrides.
#ansible#yaml#architecture
Flagship #10 · PublishedAnsible & RHCE
Ansible Vault with two vault IDs, without typing a password
Mapping multiple vault IDs to files, with automated password scripts for unattended execution.
#ansible#security#vault#ci-cd
Flagship #11 · PublishedCloud & Identity
The mobile access runbook: Company Portal, work profile and the copy-paste block
Enroll phones in Intune first, gate Microsoft 365 on compliance with report-only Conditional Access, then lock copy-paste inside the work profile and Office apps.
#intune#entra-id#mdm#security
Flagship #12 · PublishedRed Hat Certification
Mastering enterprise storage, advanced security and SELinux in RHEL 10
LVM provisioning, SUID/SGID/sticky semantics, POSIX ACLs and persistent SELinux policy — an end-to-end hands-on lab with exact commands for EX200 and EX294.
#rhel#rhcsa#rhce#lvm#selinux
Archive
Everything else I've written
Mirrored word for word from Hashnode and Medium by npm run sync:cross-platform. Weekly issues live under the newsletter.
Hashnode
How a 732-Byte Python Script Can Escape Your Kubernetes Cluster — Copy Fail, Explained
Learn how the kubectl cp command can be weaponised using path traversal to escape Kubernetes clusters. Covers CVE-2019-11246, real exploit code, and…
Hashnode
How to Extract (Unzip) tar.xz File: A Complete Beginner's Guide
Learn how to extract a tar.xz file easily on Linux, Windows, and macOS. A complete beginner-to-intermediate guide with real-world examples, commands.
Hashnode
How to Allow SSH Root Login on Linux (Securely): Real-World Use Cases & Best Practices
How to Enable SSH Root Login (Ubuntu/Debian/Rocky) — Secure Steps Stepwise instructions to enable root SSH on Ubuntu/Debian/Rocky Linux with security
Hashnode
Beginner's Guide to Building a Professional CI/CD Pipeline from Scratch
Learn the fundamentals of building a CI/CD pipeline using GitHub Actions, Docker, and AWS for Node.js apps in this comprehensive beginner's guide
Hashnode
Boost LinkedIn Automation: Creating Content with n8n and Google Gemini
Automate LinkedIn content creation using n8n, Google Gemini, and a human-in-the-loop workflow for consistent, high-quality posts effortlessly
Hashnode
Managing AWS IAM Users Made Easy: Tips on Creation, Administration, and Removal
Learn to manage AWS IAM users effectively with easy-to-follow steps for creation, administration, and removal, plus best security practices
Hashnode
Comprehensive DNS Propagation Checker and Deep Trace Tool: 2025 Guide
CheckYourDNS: A deep tracing tool for DNS diagnostics, offering real-time propagation verification and instant visibility for tech professionals
Hashnode
Resolving IP Conflicts in Talos Kubernetes: A Step-by-Step Guide
Learn how to resolve IP conflicts in Talos Kubernetes labs with this detailed, step-by-step troubleshooting guide
Hashnode
The Comprehensive Guide to Deploying n8n in Production: A Docker Deployment Journey
Learn how to deploy n8n in production using Docker, PostgreSQL, and Caddy to automate workflows securely and efficiently for your business
Hashnode
Learn YAML Fast: Your First Step to DevOps Mastery
Master YAML syntax, Docker Compose, and Kubernetes manifests with this comprehensive guide for aspiring DevOps engineers
Hashnode
Step-by-Step Guide: Setting Up a Web Server with Virtual Hosts on Ubuntu
Learn to set up Apache Virtual Hosts on Ubuntu to host multiple websites effectively with this comprehensive step-by-step guide
Hashnode
Simple Ways to Install VLC on Linux (Ubuntu, Fedora, Centos & More)
Learn five easy methods to install VLC on Linux, including Ubuntu, Fedora, and more, for seamless media playback
Hashnode
Discovering the Power Behind Popular Linux GUI Applications
Explore how popular Linux GUI applications like GIMP, LibreOffice, GNOME System Monitor, Cheese, and Shotwell rely on powerful command-line tools…
Medium
How NYSE moved to Linux and Reduced infra cod.
In the fast-paced world of global finance, the New York Stock Exchange (NYSE) stands as an iconic symbol of capitalism and financial power. For over two centuries, it has driven the pulse of the global economy, adapting
Hashnode
A Beginner guide to "iotop" to for checking your Hard Disks
iotop watches I/O usage information output by the Linux kernel (requires 2.6.20 or later) and displays a table of current I/O usage by processes or threads
Hashnode
Mastering Multiple Domains: How to Set Up a Web Server with Virtual Hosts on Ubuntu
A virtual host is a single server that can power and deploy multiple websites on one machine. It allows multiple domains or subdomains to share the same IP
Medium
Jenkins: Your Automation Arsenal for Secure and Efficient DevOps and SRE
Welcome to another story here. In this story we are covering the Jenkins power and how a Fintech understood the power of Jenkins.
Medium
C++: The Powerhouse Behind Apple’s Infrastructure
C++, a veteran in the programming world, might not always make headlines, but its influence is undeniable. Apple, a tech giant known for its sleek design and user-friendly experience, heavily relies on C++ to power its v
Medium
Unleash the Night: How to Force Dark Mode in Chrome and Edge with Flags
Embrace the dark side, web warriors! Today, we’re diving into the hidden depths of Chrome and Edge to unleash a powerful tool: force dark mode using flags.
Medium
Python Empowering Rackspace: From Infrastructure to Support
In the ever-evolving landscape of cloud services, one name stands out for its exceptional management and support: Rackspace. While Rackspace has been a trailblazer in managed cloud solutions, it has found a reliable comp
Medium
Mastering AWS IAM Users: Creating, Managing, and Deleting with Confidence
Introduction: Amazon Web Services (AWS)(https://en.wikipedia.org/wiki/AmazonWebServices) is a vast cloud ecosystem that offers immense flexibility and power. However, with great power comes great responsibility. Managing