4 Systems & infrastructure
Every entry filed under Systems & infrastructure and its subtopics.
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- You are new to this topic.
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- You use it, and want to get better.
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- You know it well and need the details.
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238 entries
- 0375 Fix: disk full, find what is eating the space A Linux filesystem reports 100 percent used or No space left on device. Find the culprit with df and du, check journals,… Intermediate · Fixes an error · Linux Article Alerting & dashboards · Disks, LVM & filesystems 15 Oct 2026
- 0394 Install kubectl on Linux, macOS and Windows Install the Kubernetes command-line client with curl, a package manager or winget, verify it, and point it at a cluster with a… Beginner · Step by step · Linux, macOS, Windows Article Concepts · Installing languages & tools 15 Oct 2026
- 0396 PowerShell basics: cmdlets, objects and the pipeline PowerShell commands are called cmdlets, they return objects instead of text, and the pipeline passes those objects between them. Once that clicks,… Beginner · Explains an idea · Linux, macOS, Windows Article PowerShell 15 Oct 2026
- 0377 Netdata: real-time, per-second monitoring with zero configuration The Netdata repository: an agent that auto-discovers hundreds of metrics on Linux hosts, containers and common services, shows them per second in… Linux, macOS Repo Alerting & dashboards · Prometheus & Grafana 15 Oct 2026
- 0397 PowerShell cheat sheet The PowerShell cmdlets and patterns you use every day: files, text, processes, services, filtering, exporting, remoting and the operators that trip up… Beginner · Cheat sheet · Linux, macOS, Windows Article PowerShell 15 Oct 2026
- 0391 Install Docker on Linux, macOS and Windows Docker Desktop or Docker Engine? Pick the right one for your OS, install it, and confirm with docker run hello-world. Covers the… Beginner · Step by step · Linux, macOS, Windows Article Docker basics · Installing languages & tools 15 Oct 2026
- 0399 Fix: running scripts is disabled on this system (execution policy) PowerShell refuses to run .ps1 files until the execution policy allows it. The usual fix is RemoteSigned for your own user; here… Beginner · Fixes an error · Windows Article PowerShell · Windows administration 15 Oct 2026
- 0373 Loki: ship and search logs Run Loki, Grafana Alloy and Grafana with Docker Compose, collect the systemd journal and /var/log files with a short Alloy configuration, and… Intermediate · Step by step · Linux Article Logs 15 Oct 2026
- 0376 Loki: horizontally scalable log aggregation inspired by Prometheus The Grafana Loki repository: a log store that indexes labels instead of full text, queried with LogQL from Grafana or logcli, with… Linux, macOS Repo Logs 15 Oct 2026
- 0374 Alert rules that do not wake you for nothing How to design alerts people trust: alert on symptoms not causes, use for durations, separate page from ticket severities, group and inhibit… Intermediate · Explains an idea · Any system Article Alerting & dashboards 15 Oct 2026
- 0398 Install WSL2 and Ubuntu on Windows One command installs the Windows Subsystem for Linux and Ubuntu. Then learn how to pick a distribution, check which WSL version you… Beginner · Step by step · Windows Article Windows administration · WSL 15 Oct 2026
- 0357 Keep secrets out of git: .env files, gitignore and what to do after a leak Load passwords and API keys from an untracked .env file, commit a safe .env.example instead, catch mistakes before they are pushed, and… Beginner · Step by step · Any system Article Housekeeping · Secrets & access 15 Oct 2026
- 0347 Port check script: test a list of host:port pairs with timeouts A bash script that tries a TCP connection to each host:port you give it, waits a few seconds at most, and reports… Beginner · Cheat sheet · Linux, macOS Script DNS, IP addresses & ports · Firewalls 15 Oct 2026
- 0353 fail2ban: block repeated failed logins Install fail2ban, enable the sshd jail with sane ban times, whitelist your own address, read the ban list, unban someone, and add… Intermediate · Step by step · Linux Article Server hardening · SSH 15 Oct 2026
- 0348 DNS check script: compare answers from several resolvers A bash script that looks up one or more names against your system resolver and three public resolvers, shows each answer with… Beginner · Cheat sheet · Linux, macOS Script DNS, IP addresses & ports 15 Oct 2026
- 0358 SSH server audit script: print risky sshd settings A read-only bash script that asks sshd for its effective configuration, compares the important settings with safe values, flags config.d files that… Intermediate · Cheat sheet · Linux Script Server hardening · SSH 15 Oct 2026
- 0351 Pi-hole: network-wide ad blocking with your own DNS server A DNS server for your home or office network that answers queries for known advertising and tracking domains with nothing, so every… Linux Repo DNS, IP addresses & ports · VPN & tunnels 15 Oct 2026
- 0359 fail2ban: ban hosts that fail to log in too often The standard intrusion-prevention daemon on Linux servers: it watches logs or the journal for repeated failures and adds temporary firewall rules against… Linux Repo Server hardening · SSH 15 Oct 2026
- 0362 The 3-2-1 backup rule, and why a backup you never restored is not a backup Three copies, two kinds of media, one off-site: what the rule really protects against, how it maps to real tools, and why… Beginner · Explains an idea · Any system Article Strategy & restore drills 15 Oct 2026
- 0352 Harden a fresh Linux server in 30 minutes The baseline for any new Debian, Ubuntu or RHEL-family server: updates on, a non-root user with sudo, SSH keys only, a firewall… Beginner · Step by step · Linux Article Server hardening · Users, sudo & hardening 15 Oct 2026
- 0363 Restore drill: prove your backup works in 15 minutes A repeatable procedure to restore one file and one database from your newest backup into a scratch location, compare the result with… Intermediate · Step by step · Linux, macOS Article Backup tools · Strategy & restore drills 15 Oct 2026
- 0354 sudo rules: give a user exactly the rights they need Write sudoers rules with visudo: full admin for operators, a short list of commands for a deploy account, no-password rules for automation,… Intermediate · Step by step · Linux Article Secrets & access · Users, sudo & hardening 15 Oct 2026
- 0372 Grafana: your first dashboard from Prometheus data Connect Grafana to a Prometheus server, build a four-panel host dashboard with PromQL queries, set units and thresholds, add an instance variable,… Beginner · Step by step · Browser, Linux, macOS Article Prometheus & Grafana 15 Oct 2026
- 0367 verify-latest-backup: alert when the newest dump is too old or too small A read-only bash check that finds the newest file in a backup directory, compares its age and size against limits, optionally tests… Beginner · Step by step · Linux Script Backups & syncing · Strategy & restore drills 15 Oct 2026
- 0365 Proxmox Backup Server: first setup and first restore Install Proxmox Backup Server, create a datastore and a backup user, connect it to Proxmox VE as storage, run the first VM… Intermediate · Step by step · Linux Article Backup & restore · Backup tools 15 Oct 2026
- 0364 Schedule PostgreSQL and MySQL dumps with systemd timers Write one dump script for PostgreSQL and MySQL, run it from a systemd service and timer instead of cron, keep two weeks… Intermediate · Step by step · Linux Article Backup tools · PostgreSQL 15 Oct 2026
- 0366 restic backup wrapper with tagging, retention and a weekly check A bash wrapper that runs restic backup on a fixed list of paths, applies a keep-daily/weekly/monthly policy with forget and prune, runs… Intermediate · Step by step · Linux, macOS Script Backup tools · Backups & syncing 15 Oct 2026
- 0368 restic: fast, encrypted, deduplicated backups to local disk, SFTP or cloud storage The restic repository: a single Go binary that backs up to local disks, SFTP, S3, Backblaze B2, Azure, Google Cloud and anything… Linux, macOS, Windows Repo Backup tools 15 Oct 2026
- 0345 SSH keys: create, copy and use them Generate an ed25519 key pair, install the public key on a server with ssh-copy-id, keep the private key protected with a passphrase… Beginner · Step by step · Linux, macOS, Windows Article Keys & config · SSH 15 Oct 2026
- 0344 ufw and firewalld: open and close ports Allow and remove ports and services on the two standard Linux host firewalls, restrict a port to one source network, and make… Beginner · Step by step · Linux Article Firewalls · Networking & firewalls 15 Oct 2026
- 0371 Where are the logs? journalctl, /var/log and container logs A practical map of where Linux programs write their logs and the commands to read them: journalctl filters, the classic files under… Beginner · Step by step · Linux Article Logs 15 Oct 2026
- 0369 BorgBackup: deduplicating archiver with compression and authenticated encryption The BorgBackup repository: a Python and C backup tool that stores deduplicated, compressed, encrypted archives on local disks or over SSH, with… Linux, macOS Repo Backup tools 15 Oct 2026
- 0346 The SSH config file: aliases, jump hosts and keys per server Reference for ~/.ssh/config: short names for servers, the right user, port and key per host, ProxyJump through a bastion, connection reuse and… Intermediate · Cheat sheet · Linux, macOS, Windows Article Keys & config · SSH 15 Oct 2026
- 0349 Set up a WireGuard VPN with wg-easy in Docker Run a WireGuard server with a web admin page on one Linux host, open the UDP port, add a client from the… Intermediate · Guided project · Linux Article Networking & firewalls · VPN & tunnels 15 Oct 2026
- 0361 dev-sec ansible-collection-hardening: tested hardening roles for Linux, SSH and nginx An Ansible collection that applies a well-documented hardening baseline to Linux hosts, the SSH server and client, nginx and MySQL, with every… Linux Repo Ansible · Server hardening 15 Oct 2026
- 0370 rclone: rsync for cloud storage, with 70+ providers The rclone repository: a Go command-line tool that copies, syncs, mounts and checks files across local disks and more than 70 cloud… Linux, macOS, Windows Repo Backup tools 15 Oct 2026
- 0350 wg-easy: WireGuard VPN with a web admin interface A Docker image that runs a WireGuard server and a web page to create clients, show QR codes and watch traffic. The… Linux Repo VPN & tunnels 15 Oct 2026
- 0355 TLS certificates explained What a certificate proves, who signs it, what the chain and expiry mean, and how to read any site's certificate from the… Beginner · Explains an idea · Any system Article TLS & certificates 15 Oct 2026
- 0356 Free HTTPS with Let’s Encrypt and certbot Install certbot, get a trusted certificate for your domain and let it configure nginx or Apache, or just obtain the files for… Beginner · Step by step · Linux Article TLS & certificates 15 Oct 2026
- 0360 certbot: the Let’s Encrypt client The EFF's ACME client that obtains free TLS certificates from Let's Encrypt, can configure nginx and Apache for HTTPS automatically and renews… Linux Repo TLS & certificates 15 Oct 2026