AAlbertinahlbert.hashnode.dev·5h ago · 3 min readI turned on Secure Boot and my Ubuntu laptop stopped bootingI have an old HP EliteBook Folio 9470m (2014, BIOS F.48) running Ubuntu. I had just upgraded to the latest version Ubuntu 26.04.1 LTS resolute, and I thought I would turn on Secure Boot while I was at00
DVDanila Vershininingetpagespeed.hashnode.dev·2h ago · 10 min readNGINX Microcaching: Varnish-Style Full-Page Caching Without a Third-Party ModuleYour WordPress homepage takes 600 to 900 ms to build. Your API endpoint runs the same database query a thousand times a second. The pages barely change from one second to the next, yet every visitor p00
ASAsep Sayyadinasepsayyad007.hashnode.dev·2h ago · 19 min readHunting the Ghost in the Machine: Why Our Linux Servers Kept Spiking to 100% CPU (And Why the Monitoring Script Was Lying)A deep dive into CPU delta calculations, isolated Docker metric samplers, and disabling rogue systemd timers. The Telegram notification arrived at 03:14 AM. ALERT: [prod-app-02] CPU utilization is a00
PGPro Gineousinprogineous.hashnode.dev·1d ago · 4 min readSecure a Linux VPS in 15 MinutesYou just got root on a fresh Ubuntu box. That is power and risk in the same login. Attackers scan new IPs within minutes. This walkthrough hardens a typical Ubuntu 22.04 or 24.04 VPS in about a quarte12V
ASAsep Sayyadinasepsayyad007.hashnode.dev·12h ago · 15 min readZero-Trust Linux: How I Hardened 4 Cloud Servers Against Brute-Force Attacks in Under an HourNo passwords, no root login, and aggressive Fail2ban jails: transforming noisy, attacked ports into impenetrable fortresses. Spin up a fresh Linux virtual machine on any major cloud provider, assign i00
N|Nitin | RouterIPGuideinrouteripguide.hashnode.dev·14h ago · 5 min readWhy Routers Automatically Shift From 192.168.1.1 to 10.0.0.1 or 192.168.2.1 (Understanding Subnet Collisions)If you have ever plugged a brand-new Netgear, TP-Link, or ASUS Wi-Fi router into an existing ISP fiber ONT or cable modem, tried to open 192.168.1.1, and watched your browser fail to connect—or worse,00
SPSai Piseyinsaipisey.hashnode.dev·23h ago · 2 min readOne command tells you if your next Kubernetes upgrade will brick a nodeSince v1.35, the kubelet setting failCgroupV1 defaults to true. On a node that still runs cgroup v1, the kubelet refuses to start, so the node goes NotReady and stays there. On a control-plane node it11V
UGUnnati Guptaindevunnatig.hashnode.dev·1d ago · 7 min readDAY-1: Linux Internals — Understanding User Space, Kernel Space, System Calls, and /proc1. What Is the Linux Kernel? The kernel is the core of the Linux operating system. It acts as the bridge between applications and the underlying hardware. Although it is possible to run programs on a 00
MEMiller Eliasineliasmiller.hashnode.dev·1d ago · 8 min readDemystifying Cron Expressions: Dialects, Daylight Saving Traps, and Drift in Modern Distributed SystemsCron expressions have powered background task automation since Brian Kernighan introduced the cron utility in Version 7 Unix in 1979. Over four decades later, whether you are triggering nightly databa01V
ASAsep Sayyadinasepsayyad007.hashnode.dev·1d ago · 20 min readWhy a Deleted Linux File Can Still Consume Disk SpaceYour root partition is at 100%, you ran rm on a 50GB log file, and df still reports zero free bytes. Here is how inodes, unlinked file descriptors, and kernel references keep ghost data alive, and how01V
