User account management is one of the most fundamental administrative tasks on any Linux server. On Red Hat Enterprise Linux 9, every process, file, and network socket is owned by a user and group, making correct account hygiene essential for both security and auditability. Understanding the full lifecycle — creation, modification, and removal — and […]
Nagios Core is a widely-used open-source infrastructure monitoring system that alerts administrators to host and service failures. On RHEL 9, Nagios Core must be compiled from source since no official RPM package is maintained for the current release. This guide walks you through building Nagios Core 4.x, installing the standard plugins, securing the web interface […]
BIND9 (Berkeley Internet Name Domain version 9) is the most widely deployed DNS server software in the world and is fully supported on RHEL 9 through the bind package. Running your own authoritative DNS server lets you resolve hostnames for domains you control without relying on a third-party provider. This tutorial covers installing BIND9, writing […]
Kubernetes Role-Based Access Control (RBAC) is the mechanism for controlling which users and service accounts can perform which actions on which resources within a Kubernetes cluster. Without RBAC configuration, all authenticated users (and service accounts in pods) have full admin access — a significant security risk in multi-team environments. RBAC uses four resource types: Role […]
Pulumi is a modern Infrastructure as Code platform that lets you define, deploy, and manage cloud resources using general-purpose programming languages — Python, TypeScript, Go, C#, and Java — instead of a domain-specific language like Terraform’s HCL. This means you get real loops, conditionals, functions, classes, and access to the full ecosystem of your chosen […]
Kubernetes separates storage provisioning (creating storage volumes) from storage consumption (using volumes in pods) through two resource types: PersistentVolumes (PVs) and PersistentVolumeClaims (PVCs). A PersistentVolume is a piece of storage in the cluster provisioned by an administrator or dynamically by a StorageClass. A PersistentVolumeClaim is a request for storage by a user — it specifies […]
ClickHouse is a column-oriented database management system (DBMS) designed for Online Analytical Processing (OLAP). Unlike row-oriented databases (MySQL, PostgreSQL) where each row is stored together — efficient for retrieving full records — ClickHouse stores each column separately, making it extremely efficient for aggregation queries that scan specific columns across billions of rows. ClickHouse can process […]
Pluggable Authentication Modules (PAM) is the authentication framework at the heart of every RHEL 8 login, password change, and session management operation. PAM allows system administrators to configure authentication policies without modifying individual applications — by editing stack files in /etc/pam.d/, you can enforce account lockout after failed attempts, require strong passwords, limit resource usage, […]
PHP-FPM (FastCGI Process Manager) is the recommended interface between Nginx and PHP on RHEL 8, replacing the older mod_php approach with a more flexible and performant process pool model. Rather than embedding PHP inside the web server, PHP-FPM runs as a separate systemd-managed service that Nginx communicates with over a Unix socket, isolating the two […]
Without a log rotation strategy, application log files will grow unbounded until they fill your disk and bring services down. Logrotate is the standard RHEL utility that automates log file rotation, compression, and cleanup on a scheduled basis with no daemon process required. It runs daily via a cron job and processes configuration rules you […]
