4 Systems & infrastructure
Every entry filed under Systems & infrastructure and its subtopics.
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Works on
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- Beginner
- You are new to this topic.
- Intermediate
- You use it, and want to get better.
- Advanced
- You know it well and need the details.
- Guided project
- Build something small from start to finish, step by step.
- Explains an idea
- Plain words on how something works and why.
- Step by step
- Numbered steps to get one task done.
- Cheat sheet
- Commands and options in a table, to look up fast.
- Fixes an error
- An error message, what it means, and how to solve it.
238 entries
- 0277 What is TLS? TLS is the encryption layer that puts the S in HTTPS, protecting data between your browser and a server. Beginner · Explains an idea · Any system Article TLS & certificates 15 Oct 2026
- 0276 What is SSH? SSH is a secure way to open a command line on another computer over the network, with everything encrypted. Beginner · Explains an idea · Any system Article SSH 15 Oct 2026
- 0272 What is a virtual machine? A virtual machine is a complete computer made of software, running inside another computer with its own operating system. Beginner · Explains an idea · Any system Article Basics 15 Oct 2026
- 0278 What is a certificate? A certificate is a digital ID card that proves a website or server is genuine, issued by a trusted authority. Beginner · Explains an idea · Any system Article TLS & certificates 15 Oct 2026
- 0273 What is a hypervisor? A hypervisor is the software layer that creates and runs virtual machines and shares the real hardware between them. Beginner · Explains an idea · Any system Article Basics 15 Oct 2026
- 0265 Turn a one-liner into a robust bash script: strict mode, options, logging, traps, locking and a schedule Grow a find-and-gzip one-liner step by step into a dependable bash script with strict mode, getopts, usage text, logging, error traps, dry-run,… Intermediate · Guided project · Linux, macOS Article Services & systemd · Shell scripting 15 Oct 2026
- 0250 Containerize a Node.js app and run it with PostgreSQL using Docker Compose Package a small Node.js web app in a multi-stage Docker image, then run it next to PostgreSQL with Docker Compose, named volumes,… Intermediate · Guided project · Linux, macOS, Windows Article Docker basics · Docker Compose · PostgreSQL 15 Oct 2026
- 0251 Learn Kubernetes on your laptop with kind: from first cluster to Ingress Build a throwaway Kubernetes cluster in Docker with kind, deploy a web app with config, secrets and probes, scale it, roll out… Beginner · Guided project · Linux, macOS, Windows Article Concepts · Workloads & services 15 Oct 2026
- 0256 Manage infrastructure as code with Terraform: from first file to plans on pull requests Learn the full Terraform workflow without a cloud account: variables, a module, outputs, state, plan, apply and destroy, a backend for shared… Beginner · Guided project · Linux, macOS, Windows Article GitHub Actions · Terraform 15 Oct 2026
- 0255 Build a monitoring stack with Prometheus, node_exporter and Grafana on one Linux server Install Prometheus and node_exporter as systemd services, scrape and query host metrics with PromQL, then add Grafana with a dashboard and an… Intermediate · Guided project · Linux Article Prometheus & Grafana · Services & systemd 15 Oct 2026
- 0252 Package a web app as a Helm chart: create, test, install, upgrade and roll back Turn a small nginx web app into your own Helm chart, check it with lint and template, install it into a namespace,… Intermediate · Guided project · Any system Article Helm 15 Oct 2026
- 0249 Set up and harden a fresh Linux server in one afternoon Take a new Ubuntu, Debian or Rocky/Alma server from first login to a safer baseline: sudo admin, SSH keys only, firewall, automatic… Beginner · Guided project · Linux Article Networking & firewalls · Packages & updates · Users, sudo & hardening 15 Oct 2026
- 0248 Run your first KVM virtual machine with libvirt and virt-install Turn a Linux desktop or server into a KVM host: check CPU support, install libvirt, use the default NAT network, create a… Beginner · Guided project · Linux Article Basics 15 Oct 2026
- 0247 Build a Proxmox VE home lab: from bare metal to your first restored backup Install Proxmox VE on one spare machine, switch to the free update repository, create a VM and an LXC container, then schedule… Beginner · Guided project · Linux Article Backup & restore · Installation & first steps · VMs & containers 15 Oct 2026
- 0253 Take an app to production on OpenShift: S2I build, TLS Route, storage, autoscaling and network policy Build a small Python app from Git with Source-to-Image on OpenShift or OKD, then add an HTTPS Route, config and secrets, storage,… Intermediate · Guided project · Linux, macOS, Windows Article Concepts · Deploying applications 15 Oct 2026
- 0254 Automate three servers with Ansible: roles, templates, Vault and safe dry runs Build a real Ansible project for two web servers and one database server: inventory groups, SSH keys, roles, templates, handlers, an encrypted… Intermediate · Guided project · Linux, macOS Article Ansible · Keys & config 15 Oct 2026
- 0193 Linux logs reference: journalctl, journald storage, logrotate and centralized logging Read and filter systemd journal logs, keep their disk use in check, rotate classic log files with logrotate, and understand when to… Intermediate · Cheat sheet · Linux Article Linux administration · Logs 15 Oct 2026
- 0169 Add a new disk: partition, format and mount it by UUID Find a new disk with lsblk, partition it with parted, create an ext4 or XFS filesystem and mount it permanently through /etc/fstab… Intermediate · Step by step · Linux Article Disks, LVM & filesystems 15 Oct 2026
- 0187 Terraform concepts: providers, state, plan and apply, modules, and OpenTofu Terraform describes infrastructure in code, compares it with what exists, and changes only the difference. Learn providers, resources, state, the plan/apply loop,… Beginner · Explains an idea · Any system Article Terraform 15 Oct 2026
- 0170 LVM explained: physical volumes, volume groups and logical volumes LVM puts a flexible layer between disks and filesystems, so you can grow volumes, add disks and take snapshots without repartitioning. Intermediate · Explains an idea · Linux Article Disks, LVM & filesystems 15 Oct 2026
- 0176 apt vs dnf: package commands and automatic security updates The everyday package commands on Debian/Ubuntu (apt) and RHEL/Rocky/Alma (dnf) side by side, plus how to turn on automatic security updates on… Beginner · Cheat sheet · Linux Article Packages & updates 15 Oct 2026
- 0188 First Terraform configuration: variables, a module and outputs (no cloud needed) A complete Terraform project that writes local files with the hashicorp/local provider, so you can practice init, plan, apply, modules and destroy… Intermediate · Step by step · Any system Script Terraform 15 Oct 2026
- 0171 Extend an LVM logical volume and filesystem online (safe script) A bash script that grows the LVM volume behind a mount point, checks the filesystem type and free space first, and runs… Advanced · Step by step · Linux Script Disks, LVM & filesystems 15 Oct 2026
- 0189 Terraform remote state: backends, locking and migrating local state Move Terraform state from a local file into a shared backend such as S3 with locking, so a team can work safely.… Advanced · Step by step · Any system Article Terraform 15 Oct 2026
- 0172 Fix: No space left on device Writes fail because a filesystem is full, out of inodes, or holding space for deleted files that are still open. Find which… Beginner · Fixes an error · Linux Article Disks, LVM & filesystems 15 Oct 2026
- 0190 Fix: Terraform Error acquiring the state lock Another run holds the lock on your Terraform state, or a crashed run left it behind. Find out who holds it, wait… Advanced · Fixes an error · Any system Article Terraform 15 Oct 2026
- 0195 OpenTofu: open-source infrastructure as code OpenTofu is the community fork of Terraform under the MPL-2.0 license, run as a Linux Foundation project. It uses the same configuration… Any system Repo Terraform 15 Oct 2026
- 0177 Users, groups and sudo on Debian, Ubuntu and RHEL How Linux accounts and groups work, how to create users, and how sudo gives admin rights through the sudo group on Debian/Ubuntu… Beginner · Explains an idea · Linux Article Users, sudo & hardening 15 Oct 2026
- 0178 Create a sudo user with an SSH key and disable password login A bash script that creates an admin user in the sudo or wheel group, installs their SSH public key and can switch… Advanced · Step by step · Linux Script Keys & config · Users, sudo & hardening 15 Oct 2026
- 0191 Prometheus concepts: pull model, exporters, node_exporter and PromQL basics Prometheus scrapes numeric metrics from your systems over HTTP and stores them as time series. Learn the pull model, metric types, node_exporter,… Intermediate · Explains an idea · Linux Article Prometheus & Grafana 15 Oct 2026
- 0168 Server health check script: disk, memory and failed units A dependency-free bash script that checks disk and inode usage, available memory, load, failed systemd units and pending reboots, and exits non-zero… Intermediate · Cheat sheet · Linux Script Disks, LVM & filesystems · Services & systemd 15 Oct 2026
- 0173 Set a static IP address: nmcli on RHEL vs netplan on Ubuntu RHEL, Rocky and AlmaLinux configure networking with NetworkManager (nmcli); Ubuntu Server uses netplan YAML. Here is the same static IP setup in… Intermediate · Step by step · Linux Article Networking & firewalls 15 Oct 2026
- 0181 Ansible concepts: inventory, modules, playbooks, idempotency and roles Ansible configures many servers over SSH from one control machine. Learn the core pieces: inventory, modules, tasks, playbooks, roles, and why runs… Beginner · Explains an idea · Linux, macOS Article Ansible 15 Oct 2026
- 0192 Grafana basics: connect Prometheus, build a dashboard and set up an alert Connect Grafana to Prometheus, build a dashboard for your servers with PromQL panels and a host selector, and create an alert rule… Intermediate · Step by step · Linux Article Prometheus & Grafana 15 Oct 2026
- 0179 systemd: the Linux system and service manager The source of systemd, the init system and service manager on most Linux distributions, together with journald, networkd, resolved, timers and the… Linux Repo Services & systemd 15 Oct 2026
- 0174 Network and DNS troubleshooting commands: ip, ss, dig, resolvectl A layer-by-layer cheat sheet for "the server cannot reach X": interfaces and routes with ip, listening ports with ss, and name resolution… Beginner · Cheat sheet · Linux Article Networking & firewalls 15 Oct 2026
- 0182 Your first Ansible playbook: install nginx and publish a page A complete beginner playbook that installs nginx on Debian or Ubuntu servers, starts it at boot and deploys a home page, with… Beginner · Step by step · Linux, macOS Script Ansible 15 Oct 2026
- 0196 Prometheus: monitoring system and time series database The main Prometheus server: it scrapes metrics over HTTP, stores them as time series, answers PromQL queries and evaluates alerting rules. Linux Repo Prometheus & Grafana 15 Oct 2026
- 0175 Open ports with firewalld and ufw firewalld (RHEL, Rocky, AlmaLinux) and ufw (Ubuntu) are friendly front ends to the kernel firewall. Allow SSH first, then open only the… Intermediate · Step by step · Linux Article Networking & firewalls 15 Oct 2026
- 0183 Ansible variables, templates and handlers: configure an nginx site Use group variables, Jinja2 templates and handlers together: render an nginx server block from variables, test the config and reload nginx only… Intermediate · Step by step · Linux, macOS Script Ansible 15 Oct 2026