Ceph
Reference for Ceph, the software-defined storage platform providing object, block, and file storage on top of RADOS. Covers architecture, CRUSH, core daemons, installation, OSD management, capacity planning, monitoring, …
Linux
Clonezilla
Open-source disk imaging and cloning tool for bare-metal backup, mass deployment, and disaster recovery. Covers Clonezilla Live and SE, interactive and command-line usage, and backup verification.
Commands Cheatsheet
A categorized quick reference for core Linux commands, with deprecated tools flagged and modern replacements listed. Covers file operations, text processing, process and user management, networking, archiving, package …
Cron
Reference for the cron job scheduler: expression syntax, crontab management, environment handling, logging, debugging, systemd timer equivalents, and common pitfalls.
DeleteFilesOlderThan.sh
A bash script that finds and deletes files older than 30 days in error and processed subdirectories under a given base path. Includes cron scheduling, a dry-run variant, and simplified single-command alternatives.
Disabling CTRL+ALT+F# Virtual Terminal Switching
How to disable switching to Linux virtual terminals (Ctrl+Alt+F1 through F6) at the X11, Wayland, systemd-logind, kernel, and display-manager levels for kiosk and restricted environments.
DNS Encryption
Protocols that encrypt DNS queries and responses: DNS over TLS (DoT), DNS over HTTPS (DoH), and DNS over QUIC (DoQ). Covers transport, ports, RFCs, a protocol comparison, and implementation examples for systemd-resolved, …
DNS Record Types
Reference for common and specialized DNS resource record types, their syntax, and zone-file usage examples. Covers address, mail, security, service discovery, and DNSSEC records.
Docker CLI
Reference for the Docker command-line interface: container lifecycle, image management, builds, volumes, networking, resource constraints, backup, and troubleshooting.
etcd
Distributed key-value store built on Raft, used as the cluster state store for Kubernetes. Covers install, single-node and three-node cluster setup, TLS, RBAC, backup/restore, tuning, and monitoring.