The kernel primitives, init systems, and tooling behind the world's most-deployed OS.
Canonical's September 2021 decision to extend Ubuntu 14.04 and 16.04 LTS support to a full decade, and what it signaled about its long-term LTS commitment.
Distinguish global, cgroup, cpuset and policy-driven OOM events; interpret victim scoring and build memory controls from forensic evidence.
Understand Linux page-cache reads, buffered writes, dirty throttling and durability boundaries without confusing write completion with stable storage.
Trace Linux hardware from kernel device registration through sysfs, uevents, devtmpfs and udev rules to stable, collision-tested user-facing links.
A kernel update leaves the system unable to boot into any menu entry - how to regenerate a working GRUB2 configuration from a rescue environment.
Configuring unattended-upgrades (Debian/Ubuntu) and dnf-automatic (RHEL/Fedora) to apply security patches automatically, with sane limits on scope.
Combining two or more network interfaces into a single bonded interface with NetworkManager - for redundancy, throughput, or both, by mode.
Trace a modern Linux boot across firmware, boot manager, kernel, initramfs, real root, and PID 1 with safe diagnostics for each handoff.
Understand cgroup v2 hierarchy, controller delegation, CPU, memory, I/O and PID controls, using safe systemd workflows and kernel evidence.
Understand eBPF programs, verifier, maps, hooks, BTF and CO-RE, privileges and operational risks without treating kernel execution as a sandbox.