The Linux kernel exposes hundreds of tunable parameters through the sysctl interface, allowing system administrators to optimize network throughput, memory management, and file descriptor limits without recompiling the kernel. On RHEL 9, these tunables persist across reboots when placed in drop-in configuration files under /etc/sysctl.d/. Proper kernel tuning can dramatically reduce latency and increase throughput […]
SSH key-based authentication is the gold standard for remote server access. Unlike passwords, SSH keys cannot be guessed by brute-force attacks. An Ed25519 private key is a 256-bit secret that would take longer than the age of the universe to crack by exhaustive search. When combined with a key passphrase, you have two-factor authentication: something […]
Maven and Gradle are the two dominant build tools for Java projects. Maven uses an XML-based declarative configuration (pom.xml), follows strict conventions, and dominates in enterprise environments with heavy use of the Maven Central repository for dependency management. Gradle uses a Groovy or Kotlin DSL, is more flexible and faster than Maven (due to incremental […]
MariaDB Galera Cluster is a synchronous multi-primary cluster for MariaDB/MySQL that provides true high availability with no single point of failure. Unlike standard primary-replica replication where only one node accepts writes and replicas are read-only, Galera Cluster allows writes to any node simultaneously — all nodes are always primary, always in sync, and always up-to-date. […]
Node.js is a JavaScript runtime built on Chrome’s V8 engine that enables server-side JavaScript execution. Its non-blocking, event-driven I/O model makes it exceptionally efficient for real-time applications, REST APIs, streaming services, and microservices that handle many concurrent connections. The RHEL 9 default AppStream provides Node.js 18, but the NodeSource repository provides the latest LTS releases […]
iSCSI (Internet Small Computer System Interface) is a network protocol that allows servers to access block-level storage over a TCP/IP network, enabling centralized storage management. On RHEL 9, configuring iSCSI involves setting up a storage target that exports block devices and an initiator that connects to and mounts those devices. This tutorial covers the full […]
GitLab Community Edition (CE) is a complete, self-hosted DevOps platform that combines Git repository hosting, issue tracking, CI/CD pipelines, container registry, and code review in a single application. Hosting GitLab internally gives organisations full control over their source code without relying on third-party services, making it the preferred choice for teams with data sovereignty requirements […]
Ruby is a dynamic, object-oriented programming language best known as the language behind Ruby on Rails, the influential web framework that popularised convention-over-configuration and RESTful web applications. rbenv is the standard Ruby version manager for production servers — it allows installing and switching between multiple Ruby versions per user or per directory, without requiring root […]
Let’s Encrypt provides free, automated TLS certificates that are trusted by all major browsers. Certbot is the official ACME client that handles certificate issuance and renewal against the Let’s Encrypt CA. On RHEL 9, Certbot is available through the EPEL repository, making integration with Nginx and Apache straightforward. This tutorial walks through installing Certbot, obtaining […]
NIC bonding combines multiple physical network interfaces into a single logical interface, providing link redundancy, increased throughput, or both — depending on the bonding mode selected. On RHEL 9, NetworkManager is the canonical tool for managing bonded interfaces, replacing the older ifcfg scripts. This tutorial covers creating a bond with nmcli, adding slave interfaces, assigning […]
