LinuC Level 2 Exam 201Study guide

Go deep on the firmware layer from power-on to kernel handoff: the difference between BIOS and UEFI, the disk-layout contrast between MBR and the ESP (EFI System Partition), managing boot entries with efibootmgr, generating and installing GRUB2 config (grub-mkconfig/grub2-mkconfig, grub-install/grub2-install), and the role of initrd/initramfs.

Go deeper on operating systemd services: the three-layer config hierarchy (/usr/lib/systemd/, /etc/systemd/, /run/systemd/), unit operations with systemctl (status, list-units, start, stop, enable, disable, mask, unmask), diffing config layers with systemd-delta, and when to use rescue vs emergency mode.

Learn the structure of the kernel image itself and its source tree: the compressed executable image bzImage, the xz data compression used inside it, the kernel source tree at /usr/src/linux/, and the accompanying documentation at /usr/src/linux/Documentation/.

Learn the full workflow of building a kernel from source: the .config file and kernel Makefile, configuration make targets (config, xconfig, menuconfig, gconfig, oldconfig) versus build targets (all, bzImage, modules, modules_install), the mrproper cleanup target, packaging targets (rpm-pkg, binrpm-pkg, deb-pkg), the module install location /lib/modules/<kver>/, and how it connects to depmod, DKMS, and Dracut (mkinitrd/mkinitramfs).

Learn module management and failure analysis on a running kernel: module operations (depmod, modinfo, modprobe, insmod, lsmod, rmmod) and configuration at /etc/modprobe.d/, version checks with uname, tuning kernel parameters through procfs (/proc, /proc/sys/kernel/) and sysctl (/etc/sysctl.conf, /etc/sysctl.d/), sysfs (/sys), hardware inspection (dmesg, lspci, lsdev, lsusb, journalctl), udev rules and udevadm monitor, and crash dumps via kdump/kexec.

Learn how storage is attached to the directory tree via mounting: the persistent configuration in /etc/fstab, manual control with mount/umount, the live view in /proc/mounts, swap handling with swapon/swapoff/mkswap, and device identification with blkid/lsblk/UUID.

Learn to create, check, and maintain filesystems: creation with the mkfs family, integrity checks with fsck, ext-family tuning and backup via tune2fs/dumpe2fs/dump/restore, dedicated XFS tools (xfs_info, xfs_repair, xfsdump, xfsrestore), the next-generation Btrfs (subvolumes, snapshots, btrfs, btrfs-convert), and disk health monitoring with smartd/smartctl.

Learn flexible storage management with LVM (Logical Volume Manager): the overall lvm command and lvm.conf, and the three-layer structure of pv commands for physical volumes (PV), vg commands for volume groups (VG), and lv commands for logical volumes (LV), plus practical resizing and extension.

Learn interface configuration centered on ip: assigning IP addresses, bringing links up/down, checking the routing table; how legacy ifconfig/route/arp map to it; managing NetworkManager with nmcli; and wireless tools iw/iwconfig/iwlist.

Learn kernel tuning with sysctl (especially enabling IP forwarding), connectivity checks with ping/ping6, ad-hoc port testing with netcat (nc/ncat), packet capture with tcpdump, port scanning with nmap, and connection inspection with ss/netstat.

Learn hostname configuration (hostname, /etc/hostname), name-resolution files /etc/hosts and /etc/resolv.conf, path tracing with traceroute/traceroute6/mtr, log-based clues (dmesg, /var/log/syslog, /var/log/messages, the systemd journal), and NetworkManager plus legacy config trees /etc/network/ and /etc/sysconfig/network-scripts/.

Learn the full workflow for building software from source instead of relying on package managers: fetching source with git clone, git tag -l, and git checkout; extracting with gzip/gunzip/bzip2/xz/tar/unzip; applying diffs with patch; detecting the environment with configure; and building/installing with make and make install.

Learn backup fundamentals (full, differential, and incremental), representative backup software (Amanda, Bacula, Bareos, BackupPC), media (tape, HDD, optical), and the commands used to perform backups (dd, tar, mt, rsync).

Learn how to communicate system maintenance status to users: pre-login messages via /etc/issue and /etc/issue.net, the post-login /etc/motd, immediate broadcast to all logged-in users with wall, the shutdown-warning behavior of shutdown, and combining notification with service control via systemctl.

Learn the tools for monitoring CPU, memory, disk I/O, and network I/O: CPU with top, htop, ps, and sar; memory with vmstat, free, and sar; disk with iostat, iotop, and sar; network with netstat, iftop, ss, and sar. Also covers lsof for open files and iptraf for network traffic.

Learn the concepts behind detecting resource exhaustion, overload, and abnormal termination early: the behavior of the OOM killer, remote monitoring via SNMP, designing thresholds and alerts, and representative monitoring tools (Icinga2, Nagios, collectd, MRTG, Cacti, Zabbix).

Learn the value automation brings—standardization, efficiency, scalability, and idempotency—along with the core concepts of Ansible (inventory, modules, Playbooks, YAML), the ansible and ansible-playbook commands, and typical use cases (provisioning VMs/containers, application releases, and network device configuration changes).

Learn the difference between host-type and hypervisor-type virtualization (KVM, VirtualBox, Xen), how CPU/memory/storage/network virtualization works, the role of QEMU, hardware virtualization support (vmx/svm) checked via /proc/cpuinfo/lscpu, the kvm-intel/kvm-amd kernel modules, lifecycle management via libvirtd, virt-manager, and bridge-utils.

Learn to create virtual machines with virt-manager (GUI) and virt-install (CLI), the difference between full virtualization and paravirtualization (virtio), lifecycle operations from the command line with virsh, and performance monitoring via virt-manager.

Learn how containers differ from physical machines and VMs, and the two kernel features behind their lightness: namespaces and cgroups. Also covers the relationship between the container filesystem and its image (read-only layers plus a writable layer).

Learn day-to-day Docker operations: port mapping and the flat L2 network, inspecting state with docker ps/docker stats, lifecycle management with docker run/create/restart, pause/unpause and stop/kill/rm, working inside containers with attach/exec, the Docker registry with docker images/pull/rmi/import, and building images via Dockerfile with docker build/docker commit.