The Linux kernel’s systemd journal is a structured binary log that stores the output of every service, kernel message, boot sequence, and user session. Unlike traditional text-based syslog, the journal stores metadata alongside each log entry — the unit name, PID, UID, executable path, systemd unit state, and priority level — enabling far more precise […]
Introduction This guide explains how to Install GitLab Runner on Debian 13 on Debian 13 Trixie. Debian Trixie uses systemd for service management, nftables as the underlying packet filter (with ufw or iptables front-ends still available), and AppArmor for mandatory access control. Every command is designed for a minimal Debian 13 install with the standard […]
Introduction Deploying set up basic authentication in nginx on a Debian 13 Trixie machine is straightforward thanks to Debian’s policy-compliant packaging. Unlike rpm-based distributions, Debian stores configuration helpers in /etc/default/, uses update-rc.d for older init scripts, and provides dpkg-reconfigure for interactive package configuration. This tutorial stays on the systemd path throughout. Prerequisites You will need […]
Running out of disk space is one of the most disruptive failures a server can experience. When a filesystem fills up, applications crash, log files stop writing (losing audit trails), databases corrupt transactions, and web servers return 500 errors. Proactive disk monitoring is essential — and RHEL 9 provides a full set of tools for […]
Automated task scheduling is the backbone of server maintenance: backups run at 3 AM, log cleanup happens daily, SSL certificates renew before they expire, and databases are vacuumed weekly. On RHEL 9, there are three scheduling mechanisms each suited to different scenarios. cron is the classic daemon that runs jobs on a schedule defined by […]
🟠 High ⏱ 5–30 min Last verified: 4 November 2025 Affected versions: RHEL 10.0 RHEL 10.1 📖 ~1 min read Table of contents Symptom & Impact Environment & Reproduction Root Cause Analysis Quick Triage Step-by-Step Diagnosis Solution – Primary Fix Solution – Alternative Approaches Verification & Acceptance Criteria Rollback Plan Prevention & Hardening Related […]
rsync is the Swiss Army knife of file synchronisation for Linux administrators. Unlike scp, which blindly copies every file every time, rsync computes a rolling checksum to identify changed file blocks and transfers only what has changed — making subsequent syncs dramatically faster and less bandwidth-intensive. It preserves file attributes (permissions, ownership, timestamps, ACLs, extended […]
DNS resolution on a Linux server is a multi-layered system. When an application calls getaddrinfo(“example.com”), the request passes through the Name Service Switch (NSS) framework, which consults sources in the order defined in /etc/nsswitch.conf — typically /etc/hosts first, then a DNS resolver. The DNS resolver reads its configuration from /etc/resolv.conf, which lists the DNS servers […]
While the earlier tutorial in this series covered the core useradd, usermod, and userdel tools for user lifecycle management, this guide goes deeper into the full toolkit for managing users and groups at scale on RHEL 9: bulk creation, password management with chpasswd, group administration with gpasswd, per-user resource limits with ulimit and /etc/security/limits.conf, user […]
🟢 Low ⏱ 5–15 min Last verified: 4 November 2025 Affected versions: Ubuntu 24.04 (noble) 📖 ~4 min read • Source: Ubuntu Security Notice USN-7761-1 Related CVEs: CVE-2024-10963 CVE-2025-6020 Upstream summary: It was discovered that the PAM pam_access module incorrectly parsed certain rules as hostnames. An attacker could possibly use this issue to spoof […]
