#Linux
63 posts
RHEL Intermediate #7: Intro to Containers — Podman/Buildah/Skopeo
RHEL 9's container standard is Podman. This post looks at how it uses nearly the same commands as Docker while running without a daemon, defaulting to rootless mode, and integrating naturally with systemd — all from an operational perspective. Also covered: building images with Buildah and moving them between registries with Skopeo.
RHEL Intermediate #6: Job Scheduling — cron, systemd timer, at
Four tools for running time-based tasks in RHEL 9, from an operational perspective. Traditional cron and user crontab, anacron that catches up missed jobs when the machine was off, at for one-shot scheduling, and systemd timer as the modern replacement for cron — with a guide on which tool to use in which situation.
RHEL Intermediate #5: Log Management — journald, rsyslog, log rotation
RHEL 9 uses journald as the primary log tool and rsyslog as the secondary, with text log files rotated automatically by logrotate. This post covers journald's retention policy and disk usage control, rsyslog's continuing role as the old-guard standard, the flow of collecting logs on a central server, and how to write logrotate rules from scratch — all from an operational perspective.
RHEL Intermediate #4: Networking — NetworkManager (nmcli), bonding, teaming
RHEL 9 networking is unified under NetworkManager. This post covers: setting a static IP, DNS, and gateway with nmcli; bonding that bundles two NICs for fault tolerance; bridge as the foundation of virtual machine and container networks; and why teaming was deprecated — all in one post.
RHEL Intermediate #3: Advanced Storage — Stratis, NFS, Samba
Storage operations that reach beyond a single machine. Stratis is a storage manager built on top of LVM+XFS that lets you handle thin provisioning and snapshots with ease. NFS is the standard for sharing directories between Linux machines, and Samba is the file-sharing protocol that Windows clients can use. This post covers the setup and operation of all three tools in one place.
RHEL Intermediate #2: LVM — PV/VG/LV, Snapshots, Expansion
LVM, the standard for RHEL 9 disk operations, covered in depth. The abstraction layer between physical disks and the filesystem, the three-layer relationship of PV/VG/LV, the full flow of adding a new disk to expand an LV, capturing a pre-backup state with snapshots and rolling back, and thin provisioning and RAID options — all in one post.
RHEL Intermediate #1: Intro to SELinux — Enforcing/Permissive, Labels, Troubleshooting
A beginner-friendly introduction to SELinux, RHEL's last security layer. Covers the three modes Enforcing/Permissive/Disabled, the shape of labels (context) attached to every file and process, viewing them with ls -Z / ps -Z, fixing labels with chcon/restorecon, making permanent changes via semanage fcontext, toggling booleans, and troubleshooting AVC denials with audit2allow and sealert.
RHEL Basics #7: Basic Security — firewalld, SSH Hardening
RHEL's firewall abstraction firewalld and its zone model, the firewall-cmd command set (permanent vs runtime), the four standard SSH hardening steps — disable password auth, key-based auth, lock down root login, change the port, split sshd_config.d. The final post of the series.
RHEL Basics #6: Filesystem Basics — XFS, mount, /etc/fstab
RHEL 9's default filesystem XFS and how it differs from ext4, viewing disks with lsblk / df / du, the full cycle of partitioning a new disk, formatting with mkfs.xfs, mounting it, registering permanently in /etc/fstab via UUID, and managing swap.
RHEL Basics #5: Users / Groups / Permissions — UID/GID, sudo, ACL
The shape of /etc/passwd and /etc/shadow, the useradd / usermod / groupadd family, what rwx means and chmod's two notations, ACL (getfacl / setfacl) when finer-grained control is needed, and least-privilege sudo — all in one post.
RHEL Basics #4: Intro to systemd — Services, Targets, journalctl
systemd is RHEL's PID 1. Starting and stopping services with systemctl, enabling auto-start on boot, selecting the system's mode via targets, writing your first .service unit by hand, and reading every log in one place with journalctl.
RHEL Basics #3: dnf and Package Management — repo, modules, AppStream
Package management on RHEL is unified under one command: dnf. From everyday commands like install / remove / search / info / history, to why BaseOS and AppStream are split apart, to picking a specific version of a package via modules, to safely attaching external repos like EPEL — all in one post.