The kernel primitives, init systems, and tooling behind the world's most-deployed OS.
A complete walkthrough configuring the Linux audit daemon to watch specific files, commands, and syscalls — and actually query the resulting logs for something useful.
Using bind mounts to expose the same directory at multiple paths, and OverlayFS to layer a writable surface on top of read-only content — the two mechanisms containers are built on, directly usable on their own.
Using bpftrace's high-level scripting language to observe live kernel behavior — syscalls, function calls, scheduler events — with far less overhead and more flexibility than traditional tracing tools.
Using systemd's resource-control unit directives to cap CPU, memory, and IO for a specific service, and how to confirm the limits are actually being enforced by the kernel.
Packaging a kernel module with DKMS so it automatically rebuilds against every new kernel version, instead of breaking silently on the next kernel update.
Creating a separate network stack on the same Linux machine to test firewall rules, routing configurations, or networked software without touching the host's real network configuration.
A complete walkthrough reading, changing, and persisting kernel runtime parameters — with a few of the most commonly tuned examples explained, not just listed.
A complete walkthrough creating and running a lightweight systemd-nspawn container — useful for isolated testing environments without the overhead of a full container runtime.
Why io_uring's shared ring-buffer design eliminates most of the syscall overhead that made previous Linux async I/O interfaces disappointing in practice.
Released December 17, 2003, the 2.6 series brought in-kernel preemption, NPTL threading, SELinux, and support for far larger process/user counts — the foundation the kernel built the next two decades on.