🔧 Linux Administration Labs

Documentation and logs of system-level configurations, troubleshooting, and maintenance work toward Red Hat Certified System Administrator (RHCSA) certification.

Environment: Fedora (Host) · Rocky Linux (Lab) · RHEL (Lab) · Framework 13

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📁 Labs

Lab 01: 🖥️ Storage Management & Partitioning

• Focus: Partitioning disks with parted, file system creation, and persistent mounting via /etc/fstab.
• Status: Completed.

Lab 02: 🕰️ DNS Resolution & Time Synchronization Management

• Focus: DNS name space, resolver configuration (/etc/resolv.conf, /etc/nsswitch.conf), name resolution tools (dig, host, nslookup, getent), NTP fundamentals, Chrony configuration, stratum levels, and system time management via timedatectl.
• Status: Completed.

Lab 03: 🔐 Password Policy Management

• Focus: Configuring password aging via chage, auditing settings in /etc/shadow, and managing account locking/unlocking (passwd -l).
• Status: Completed.

Lab 04: 👥 User & Access Control Management

• Focus: User lifecycle management (useradd, usermod, userdel), group operations (groupadd, groupmod), and granular file permission manipulation (chown, chmod octal/symbolic).
• Status: Completed.

Lab 05: ⏰ Job Scheduling Management

• Focus: Implementing and managing one-time jobs (at) and recurring tasks (cron), including user access control (/etc/at.allow) and log locations.
• Status: Completed.

Lab 06: 📦 Package Management & Integrity with RPM

• Focus: Managing RPMs with rpm, dependency resolution, repository checks, and verifying package signatures.
• Status: Completed.

Lab 07: 📦 Package Management & Integrity with DNF

• Focus: Managing packages with dnf, repository configuration (ISO mounting), and package integrity verification.
• Status: Completed.

Lab 08: 🗃️ Application Sandboxing & Management with Flatpak

• Focus: Deploying containerized applications using flatpak, managing remotes (Flathub), executing isolated processes, and enforcing granular sandbox security permissions.
• Status: Completed.

Lab 09: ⚙️ System Initialization & Management

• Focus: systemd architecture, unit file hierarchy (/usr/lib/systemd/system/ → /etc/systemd/system/), managing service lifecycles (enable, disable, mask, unmask), boot target switching, and safe configuration overrides via systemctl edit.
• Status: Completed.

Lab 10: 📋 System Logging Management

• Focus: rsyslog architecture and config validation, log file inspection (/var/log/), custom message injection with logger, log rotation via logrotate, and systemd journal querying with journalctl.
• Status: Completed.

Lab 11: ⚡ Performance Tuning Management

• Focus: System tuning with tuned, profile management via tuned-adm (list, switch, recommend, off), and workload-optimized profile selection for bare metal, VM, and power-saving environments.
• Status: Completed.

Lab 12: 💾 LVM Storage Management

• Focus: Partition tables (MBR/GPT), Physical Volumes, Volume Groups, Logical Volume lifecycle (create, extend, resize, rename, teardown), filesystem formatting and persistent mounts.
• Status: Completed.

Lab 13: 💾 Swap Space Management

• Focus: Swap creation on partitions and LVM volumes, labels, priority, persistent activation via fstab, teardown, and partition labeling with xfs_admin, mke2fs, and tune2fs.
• Status: Completed.

Lab 14: 🥾 Boot Process, GRUB2, and System Recovery

• Focus: Linux boot phases (firmware → bootloader → kernel → systemd), GRUB2 configuration and interaction, boot targets, root password recovery, and broken fstab recovery via init=/bin/bash.
• Status: Completed.

Lab 15: ⚙️ Kernel Management

• Focus: Kernel package structure, /boot and /proc filesystems, kernel module inspection, installing kernels on RHEL 10 via rpm and Fedora 44 via dnf, and version verification.
• Status: Completed.

Lab 16: 🌐 Network File System Management

• Focus: NFS server/client setup, exports, firewall configuration, SSHFS client-side mounting, AutoFS direct and indirect maps, wildcard mounting, /misc built-in map, and home directory automounting.
• Status: Completed.

Lab 17: 🌐 Network Management

• Focus: Hostname management, protocols and ports, IPv4/IPv6, classful addressing, subnetting and subnet masks, CIDR notation, NetworkManager connection profiles, two-machine local networking via host table, and SFTP connectivity.
• Status: Completed.

Lab 18: 🔐 OpenSSH Service Management

• Focus: SSH architecture, symmetric/asymmetric encryption, key-based authentication, ssh-keygen, ssh-copy-id, SFTP file transfer, multi-user key distribution, authorized_keys permission repair, and PermitRootLogin control via drop-in config.
• Status: Completed.

Lab 19: 🔥 Firewall Management

• Focus: firewalld architecture, zone-based traffic management, predefined zone descriptions, service and port rules (runtime vs. permanent), live SSH block/restore demonstration, rich rules with source IP scoping, custom zone creation via XML template, zone target configuration (%%REJECT%%), interface binding, and port forwarding via firewall-cmd.
• Status: Completed.

Lab 20: 🔐 SELinux Management

• Focus: SELinux architecture (MAC vs DAC), context structure (user:role:type:level), policy enforcement, AVC, mode management (getenforce, setenforce, grubby), security contexts for processes, files, and ports, context modification with chcon, persistent labeling with semanage fcontext and restorecon, port label management, copy/move context inheritance behavior, and Boolean toggling with reboot-verified persistence.
• Status: Completed.

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Copyright © 2026 Usman Olanrewaju. All rights reserved. Licensed under the MIT License.