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Tutorials, challenges, courses, skill paths, playgrounds, and more — search the whole library in one place.

Tutorial

How Container Filesystem Works: Building a Docker-like Container From Scratch

Learn how Linux containers are built from the ground up. Starting with the mount namespace and a root filesystem, see why PID, cgroup, UTS, and network namespaces naturally follow - and how this foundation makes concepts like bind mounts, volumes, and persistence in Docker or Kubernetes much easier to grasp.

How Container Filesystem Works: Building a Docker-like Container From Scratch (cover image)
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Challenge

Pull a Deployment's Image from a Private Registry

A freshly rolled out Deployment runs an image from the team's private container registry, but its Pods are stuck in ImagePullBackOff and the catalog page returns 503. Find out why and get the Pods running.

Challenge

Harden a Django GraphQL API: Five Classic Flaws

A stock Django + Strawberry GraphQL service ships with five common weaknesses. Probe each one from the terminal, fix it in the real project, and watch the lab confirm the remediation against the live endpoint.

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Course

Kubernetes the (Very) Hard Way

A hands-on, step-by-step guide to assembling a Kubernetes cluster from the ground up, (without using any automation) while deeply exploring each component's role and functionality along the way.

Kubernetes the (Very) Hard Way (cover image)
Course
Work-in-Progress

Hands-On Firecracker: microVMs From First Principles to Production

A hands-on introduction to Firecracker that takes you from booting your first microVM to building secure, production-ready sandbox infrastructure. Learn how to launch and control microVMs, wire up networking, share data efficiently, and harden execution - the essential skills for running autonomous agents and untrusted workloads safely at scale.

Hands-On Firecracker: microVMs From First Principles to Production (cover image)
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Skill Path

Master SSH Tunnels: Local and Remote Port Forwarding

Learn how to reach an internal port on a remote machine from the local system, jump through a bastion into a private VPC, expose a development server to the Internet through a reverse tunnel, publish a home network device, and spin up a full-fledged SOCKS proxy with nothing but a regular SSH connection.

Skill Path

Docker 101: Build Container Images

Learn how to write Dockerfiles from scratch and build production-ready container images. Start with the basics of image building and progress through handling dependencies, compiling applications, inspecting image internals, and optimizing builds with multi-stage Dockerfiles. Then go deeper with advanced Dockerfile instructions, analyzing image internals, and producing multi-platform builds.

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Shell Gym

Linux 101: Meet the Linux Shell

Your first hands-on session in a Linux terminal. Practice running commands, reading their output, using arguments and options, checking whether commands succeed or fail, and chaining commands together. No prior Linux experience is required.

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Roadmap
Work-in-Progress

Docker The Hands-On Way

Master Docker by solving practical problems. The learning path includes: Must-Have and Digging Deeper routes, theoretical materials where it helps to learn faster, and cross-cutting topics such as security, debugging, and observability.

  • 1 Course
  • 15 Tutorials
  • 7 Skill Paths
  • 110 Challenges
Docker The Hands-On Way (cover image)
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Playground on  Kubernetes

Kubernetes Cluster

A multi-node Kubernetes cluster provisioned with kubeadm, allowing you to choose your preferred container runtime and networking plugin. Perfect for CKA, CKAD, and CKS preparation.

Playground on  Containers

Docker

A Linux server with Docker engine pre-installed.

Playground on  Linux

Ubuntu 26.04

A vanilla Ubuntu 26.04 server.

Playground on  Generative AI, Programming

Coding Agent Base

Get a disposable agentic coding environment in seconds. Claude Code, Codex, Gemini CLI, and Opencode pre-installed and ready to use.

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