Competencies: Infrastructure > Linux Administration
Linux Administration
Body of Knowledge
| Topic | Description | Relevance | Career Tracks |
|---|---|---|---|
Linux Fundamentals |
Filesystem hierarchy, file permissions, users/groups, processes, signals, runlevels/targets, boot process. |
Critical |
Systems Administrator, SRE, DevOps |
Package Management |
dpkg/apt (Debian), rpm/dnf/yum (RHEL), pacman (Arch), package building, repository management. |
Critical |
Systems Administrator, DevOps |
systemd |
Unit files, service management, timers, journal, targets, socket activation, dependencies, transient units. |
Critical |
Systems Administrator, SRE, DevOps |
Process Management |
ps, top, htop, kill, nice/renice, cgroups, namespaces, process states, zombie processes. |
Critical |
Systems Administrator, SRE |
User and Group Management |
/etc/passwd, /etc/shadow, useradd/usermod, groups, sudo configuration, PAM modules, LDAP integration. |
Critical |
Systems Administrator, Security Engineer |
Filesystem Management |
Partitioning, filesystems (ext4, xfs, btrfs), mount options, fstab, quotas, ACLs, extended attributes. |
Critical |
Systems Administrator, Storage Engineer |
Log Management |
journalctl, rsyslog/syslog-ng, log rotation, centralized logging, structured logging, log analysis. |
High |
Systems Administrator, SRE, Security |
Network Configuration |
NetworkManager, systemd-networkd, ip command, routing tables, DNS resolution, bonding/teaming. |
Critical |
Systems Administrator, Network Engineer |
SELinux |
Contexts, labels, booleans, policies, audit2allow, troubleshooting AVCs, confined domains, MLS. |
High |
Systems Administrator, Security Engineer |
AppArmor |
Profiles, enforce/complain modes, aa-genprof, policy development, confinement. |
Medium |
Systems Administrator (Ubuntu/SUSE) |
Performance Tuning |
sysctl, ulimits, CPU governor, I/O schedulers, memory management, profiling tools. |
High |
SRE, Systems Administrator |
Enterprise Linux (RHEL) |
Subscription management, Satellite, kickstart, PXE boot, RHCSA/RHCE skills, support lifecycle. |
High |
Systems Administrator (Enterprise) |
Personal Status
| Topic | Level | Evidence | Active Projects | Gaps |
|---|---|---|---|---|
Linux System Administration |
Advanced |
Daily driver Arch Linux; RHEL/Rocky for lab services; systemd unit authoring, journalctl analysis, user/group management, cron/timers, package management across pacman/dnf/apt |
Arch Linux Fresh Setup - VM Test & Migration Plan, Linux Administration |
No RHEL Satellite/Foreman for fleet management |
systemd |
Advanced |
Custom service units for Vault, BIND, k3s; socket activation, timer units, dependency ordering, journal filtering; debugged failed services via systemctl/journalctl |
No systemd-nspawn containers, no portable services |
|
Arch Linux |
Advanced |
Primary workstation OS — manual installation, pacman/AUR, mkinitcpio, custom kernels, systemd-boot; 3+ months terminal-first workflow |
No Arch packaging (PKGBUILD authoring), no custom ISO |
|
RHEL / Rocky Linux |
Intermediate |
Lab VMs running Rocky 9 for ISE-adjacent services; dnf, firewalld, SELinux basics; studying for RHCSA |
No RHEL 9 in production, no Kickstart/PXE automated installs |
|
SELinux |
Intermediate |
Set enforcing mode on Rocky VMs; understand contexts, booleans, audit2allow; resolved ISE-related SELinux denials |
No custom policy module authoring, no production SELinux troubleshooting at scale |
|
AppArmor |
Intermediate |
Default profiles on Ubuntu-based lab VMs; understand enforce/complain modes, profile syntax |
— |
No custom AppArmor profiles, no profile hardening workflow |