Tutorials, challenges, courses, skill paths, playgrounds, and more — search the whole library in one place.
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.
Begin with the basics to understand Docker and Kubernetes networking: learn how to create and interconnect Linux network namespaces using only command-line tools.
Learn how servers actually work by building a tiny TCP server and client from scratch. A hands-on introduction to sockets, TCP, and the network programming model every backend, DevOps, and platform engineer should go through at least once.
Learn how to limit process resources using Linux cgroups - from the most basic and labour-intensive cgroupfs manipulation to the handiest systemd-run command.
On a dual-homed Linux server, a service bound to one network's IP address may still be reachable from another network. Learn how to prevent this unexpected access without disrupting legitimate connections.
On a dual-homed Linux server, a service bound to the IP address of one interface may still accept connections that arrive through the other interface. Learn how to reach such a service through an interface it doesn't listen on, using a routing trick.
A distroless container serves a debug interface on its own loopback address. Can you reach this debug endpoint using nothing but standard Docker commands?
Practice using SHA-256 checksums to verify file integrity, detect corrupted or modified files, and confirm that downloaded data matches the original.
A heavily illustrated introduction to the first two layers of Computer Networking: Ethernet and IP. A must for any developer or DevOps engineer who wants to build solid understanding of computer networking before they move to the higher-level protocols like TCP, UDP, and even HTTP.
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.
Practice the most common Linux storage operations in a series of hands-on challenges: discover and mount drives, create partition tables, format partitions with different filesystems, map directories with bind mounts, and make mount points survive a reboot.
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.
Explore how different container runtimes - Docker, Podman, nerdctl, ctr, and runc - execute containers. Compare their UX, architecture, and impact on containerized applications.
Do you want to troubleshoot container and Kubernetes networking issues like a true expert? This is a highly practical learning path that will take you from the basics of container networking like creating a network namespace, to more complex topics like configuring a bridge network and using iptables to set up network address translation (NAT) and port forwarding.
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.
Your second hands-on session in a Linux terminal. Find out what a command name really runs, learn how to get help with --help and man pages, and stop or suspend commands that do not give the prompt back.
Your third hands-on session in a Linux terminal. Learn how the Linux directory tree is organized and practice navigating it with absolute paths, relative paths, and common shell shortcuts.
Inspect directory contents from the Linux terminal, read what a listing tells you, sort it to find the entry you need faster, and use shell patterns to name groups of files.
Your perfect base playground. Create purpose-built sandbox environments by choosing up to five VMs with custom root filesystems and organizing them into any number of local networks.
Try ShellGym - an interactive Linux command-line trainer - in a ready-made Ubuntu VM: daemon running, web UI open, sample learning path loaded.
