-
OpenStack Docs: 2026.1
(docs.openstack.org)
reference
OpenStack 2026.1 install, deployment, operations, high-availability and security guides for datacenter IaaS
-
OpenStack Installation Guide — Installation Guide documentation
(docs.openstack.org)
tutorial
node-by-node manual install of core OpenStack services on RHEL/CentOS or Ubuntu, per release
-
libvirt: The virtualization API
(libvirt.org)
tool
C/Python/Perl/Go API and daemon driving KVM, QEMU, Xen, LXC, bhyve and ESX; XML schema docs
-
Hetzner Docs
(docs.hetzner.com)
reference
guides for Hetzner Cloud, dedicated servers, Robot, DNS and Storage Boxes; low-cost EU hosting
-
The official Red Hat blog
(redhat.com)
news
Red Hat's own posts on RHEL, OpenShift, automation, edge and security; carries Enable Sysadmin
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Cockpit Project
(Cockpit Project)
tool
web console for single Linux servers: containers, storage, network, logs, built-in terminal; LGPL
-
Foreman
(theforeman.org)
tool
provisioning and lifecycle of bare-metal and cloud hosts: Puppet/Salt ENC, host groups, RBAC, Hammer CLI, API
-
Oracle Linux - Oracle Linux
(Oracle Help Center)
reference
release documentation for Oracle Linux and the Unbreakable Enterprise Kernel
-
SUSE - Open Source Solutions for Enterprise Servers & Cloud
(documentation.suse.com)
reference
SLES 16 doc set: release notes, package lifecycles, Agama installer, SELinux, PXE deploy, SLES 15 migration
-
The Debian Administrator's Handbook
(debian.org)
reference
Full book text for Debian Bullseye administration, dual CC BY-SA and GPL licensed, free to read
-
GitHub - SELinuxProject/selinux-notebook: The SELinux Notebook
(GitHub)
repo
book-length reference on SELinux policy, kernel components and userspace tools; free, HTML/PDF/EPUB
-
rsyslog 8 daily stable documentation
(docs.rsyslog.com)
reference
official docs for the usual Linux syslog daemon: RainerScript routing, filtering, Kafka output
-
NFS — The Linux Kernel documentation
(docs.kernel.org)
reference
Kernel-side NFS client and server administration: nfsroot, NFS/RDMA, admin interfaces, I/O stats
-
Open-iSCSI by open-iscsi
(open-iscsi.com)
tool
Linux iSCSI initiator per RFC 3720: iscsid daemon and iscsiadm over kernel data-path modules, GPL-2.0
-
ClusterLabs
(ClusterLabs)
tool
upstream of Pacemaker and Corosync: cluster-wide service recovery, fencing and multi-site failover
-
Pacemaker documentation
(ClusterLabs)
reference
cluster resource manager docs: Clusters from Scratch walkthrough plus exhaustive Pacemaker Explained
-
Corosync by corosync
(corosync.github.io)
tool
cluster messaging and quorum engine under Pacemaker: virtual synchrony, membership, process restart
-
Bareos Main Reference and Documentation — Bareos Documentation documentation
(docs.bareos.org)
reference
reference for Bareos network backup: director, console and webui config, Python API
-
Clonezilla - About
(clonezilla.org)
reference
Partition and disk imaging tool for bare-metal backup, recovery, and mass deployment of systems
-
Tutorials
(digitalocean.com)
reference
DigitalOcean community tutorials, a large free library of Linux server guides
-
Initial Server Setup with Ubuntu
(digitalocean.com)
tutorial
First steps on a fresh Ubuntu server: non-root user, sudo, SSH access, firewall
-
DigitalOcean
(digitalocean.com)
tutorial
nginx server blocks: hosting several sites on one machine with virtual hosts
-
About this project
(The Debian Administrator's Handbook)
reference
Debian sysadmin book by two Debian developers; free online, DFSG-compatible license, paperback sold
-
Debian Reference
(debian.org)
reference
post-installation overview of the Debian system, covering admin tasks through shell-command examples
-
Ubuntu Server documentation
(Ubuntu Server)
reference
Canonical's own server guide: installation, netplan, DNS/DHCP, firewalls, DNSSEC, Ubuntu Pro
-
Home - Documentation
(docs.rockylinux.org)
reference
docs hub for the RHEL-compatible rebuild: install, build and day-to-day admin guides, no cost
-
openSUSE Documentation
(openSUSE Documentation)
reference
Leap release notes with startup, reference, security, tuning, virtualization and AutoYaST manuals
-
Category:System administration - ArchWiki
(wiki.archlinux.org)
reference
index of ArchWiki sysadmin pages: 23 subcategories spanning maintenance and troubleshooting
-
Handbook:Main Page - Gentoo wiki
(wiki.gentoo.org)
reference
install and base-administration manual for a source-based distro: Portage, OpenRC, many CPU arches
-
Alpine User Handbook - Alpine Linux Documentation
(docs.alpinelinux.org)
reference
musl and BusyBox distro: install-to-disk steps and system components for desktop and server
-
FreeBSD Handbook
(FreeBSD Documentation Portal)
reference
official manual for installing and administering FreeBSD base systems
-
OpenBSD Frequently Asked Questions
(openbsd.org)
reference
supplemental admin guide to the man pages: console and serial setup, pf example rulesets, current release
-
The NetBSD Guide
(netbsd.org)
reference
Official NetBSD handbook: installation and day-to-day administration of the BSD base system
-
tldr pages
(tldr.sh)
tool
community-written simplified man pages: practical examples per command, clients for every platform, free
-
Unix & Linux Stack Exchange
(Unix & Linux Stack Exchange)
forum
Voted question-and-answer board where Unix and Linux users work through admin and shell problems
-
Google SRE - Site reliability engineering book Google index
(sre.google)
reference
Google's reliability practice as chapters: SLOs, toil, on-call, incident response; free to read online
-
Linux Essentials Exam 010 Objectives
(Linux Professional Institute (LPI))
reference
objectives and weightings for LPI Linux Essentials exam 010-160, version 1.6 syllabus
-
LPIC-1 Exam 101 and 102 Objectives
(Linux Professional Institute (LPI))
reference
LPIC-1 101-500/102-500 objectives v5.0 with per-topic weightings, junior Linux admin level
-
LPIC-2 Exam 201 and 202 Objectives
(Linux Professional Institute (LPI))
reference
LPIC-2 201-450/202-450 objectives with weights: mixed MS/Linux LAN, gateway and internet servers
-
Summary of LPI Certifications
(Linux Professional Institute (LPI))
reference
vendor-neutral LPI exam ladder from Essentials to LPIC-3: prerequisites, languages, validity; paid
-
Linux Professional Institute – Learning
(learning.lpi.org)
reference
hub for LPI's freely published, open-licensed courseware for teachers preparing candidates for its exams
-
Linux Foundation Certified System Administrator (LFCS) | Linux Foundation Education
(Linux Foundation - Education)
reference
exam domains and weightings: ops deployment, networking, storage; paid vendor-neutral performance exam
-
Introduction to Linux (LFS101) | Linux Foundation Education
(Linux Foundation - Education)
tutorial
no-cost self-paced beginner course: CLI basics, graphical config, major distro families
-
Linux+ Certification V8 | CompTIA
(comptia.org)
reference
CompTIA Linux+ V8 objectives and exam details: hardening, automation, containers, paid exam
-
Server+ (Plus) Certification | CompTIA
(comptia.org)
reference
CompTIA Server+ V5 objectives: server hardware, administration, security, disaster recovery; paid exam
-
DevOps Roadmap: Learn to become a DevOps Engineer or SRE
(roadmap.sh)
reference
Interactive skill tree for the DevOps/SRE career path: practices, delivery culture, free to use
-
Linux Roadmap
(roadmap.sh)
reference
community-built learning path ordering Linux skills as a step-by-step skill tree, free to use
-
Salt User Guide — Salt user guide
(docs.saltproject.io)
reference
Salt core concepts for remote execution and declarative state, community-written companion to the docs
-
Introduction
(syslog-ng documentation)
reference
admin and developer guides for the open-source edition: install, configure and tune log collection
-
Alertmanager | Prometheus
(prometheus.io)
reference
Deduplicates, groups, silences and routes Prometheus alerts to email, PagerDuty and OpsGenie
-
Kea DHCP
(isc.org)
tool
ISC's multi-threaded DHCPv4/v6 server with REST API and Stork dashboard, MPL-2.0
-
Kea Administrator Reference Manual — Kea 3.2.0 documentation
(kea.readthedocs.io)
reference
ISC's DHCPv4/DHCPv6 server administration reference for 3.2.0: configuration and hook libraries, open source
-
chrony – Introduction
(chrony-project.org)
tool
NTPv4 client, server and peer for hosts with intermittent links or uptime; chronyd plus chronyc
-
pool.ntp.org: the internet cluster of ntp servers
(ntppool.org)
organisation
volunteer cluster of ~6,100 public time servers, the default NTP source for most distros; free