Kernel Drivers

How to Install Apache HTTP Server on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Install Apache HTTP Server on RHEL 9

Apache HTTP Server (httpd) is the most historically significant web server in the history of the internet, powering billions of websites since 1995. On RHEL 9, Apache is available as httpd from the AppStream repository and integrates with SELinux, firewalld, and systemd. Apache’s module architecture makes it highly extensible: mod_rewrite for URL manipulation, mod_ssl for […]

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How to Manage System Packages with dnf on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Manage System Packages with dnf on RHEL 9

dnf (Dandified YUM) is the default package manager for RHEL 9 and the successor to yum. It handles installing, updating, removing, and querying RPM packages from local and remote repositories, resolving dependencies automatically using the libsolv library, and supporting transactions that can be rolled back if something goes wrong. For Red Hat Enterprise Linux, packages […]

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How to Perform a System Security Audit with auditd on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Perform a System Security Audit with auditd on RHEL 9

Security auditing is the practice of recording and reviewing system calls, file accesses, user actions, and configuration changes to detect policy violations, investigate incidents, and demonstrate compliance with standards like PCI DSS, HIPAA, and SOC 2. On RHEL 9, the Linux Audit Framework — provided by the auditd daemon — captures events at the kernel […]

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How to Use journalctl for Systemd Log Analysis on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Use journalctl for Systemd Log Analysis on RHEL 9

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 […]

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How to Monitor Disk Usage with df, du, lsblk and ncdu on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Monitor Disk Usage with df, du, lsblk and ncdu on RHEL 9

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 […]

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How to Configure Automatic Security Updates on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure Automatic Security Updates on RHEL 9

Unpatched software is the leading cause of server compromise. The majority of publicly disclosed vulnerabilities already have patches available by the time attackers start actively exploiting them — the window between patch availability and active exploitation has shrunk from months to days. Manually patching servers is error-prone and inconsistent at scale. Automatic security updates ensure […]

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How to Create and Manage Swap Space on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Create and Manage Swap Space on RHEL 9

Swap space acts as overflow memory. When the physical RAM is full, the Linux kernel moves the least-recently-used memory pages to swap on disk, freeing physical RAM for active processes. Without swap, when RAM is exhausted the Out of Memory (OOM) killer terminates processes — often the largest one, which is frequently your database or […]

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How to Monitor System Resources with htop, top and vmstat on RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

How to Monitor System Resources with htop, top and vmstat on RHEL 9

Every Linux administrator needs a reliable toolkit for answering the question “why is this server slow?” The answer is almost always in one of four resources: CPU, memory, disk I/O, or network. RHEL 9 includes several powerful tools for diagnosing resource contention: top is included in every base installation and provides a real-time process table; […]

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Initial Server Setup with RHEL 9 — step-by-step RHEL 9 tutorial on Progressive Robot

Initial Server Setup with RHEL 9

Red Hat Enterprise Linux 9 (RHEL 9, codenamed “Plow”) is the most significant release of RHEL in years, built on Linux kernel 5.14, OpenSSL 3.0, and shipped with a hardened-by-default security posture including SELinux enforcing mode, nftables as the default firewall backend, and full support for the latest POWER, ARM, and x86_64 architectures. Whether you […]

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How to Configure the Firewall on RHEL 9 with firewalld — step-by-step RHEL 9 tutorial on Progressive Robot

How to Configure the Firewall on RHEL 9 with firewalld

Red Hat Enterprise Linux 9 uses firewalld as its default firewall management daemon, backed by nftables as the kernel netfilter framework (replacing iptables which was the default in RHEL 7 and earlier). firewalld provides a zone-based model where each network interface is assigned to a trust zone — public, internal, dmz, trusted, and more — […]

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