The storage driver is the layer between a container’s filesystem and the host’s disk. It determines how image layers are stacked, how writes are handled, and how much space and inode overhead the container incurs. Docker supports several drivers, but overlay2 is the default on most Linux distributions and the one most LFCS and Docker…
A container’s root filesystem is writable by default. The application can write to any directory that its user has permission to write to, including the directories where the application’s own binaries and configuration files live. This is convenient for development and for applications that assume they can write anywhere. It is also a security liability….
A volume driver is the mechanism that determines where a volume’s data actually lives. The default driver stores it on the local host filesystem. Other drivers store it on an NFS server, a cloud block device, or a distributed storage cluster. The driver is specified when the volume is created, and it determines the volume’s…
A volume is a Docker-managed storage location that exists outside the container’s lifecycle. It is created, listed, inspected, and removed through the docker volume command family. Unlike a bind mount, which is a host path that Docker maps into a container, a volume is a first-class object with its own name, metadata, and driver. Docker…
A container’s writable layer is ephemeral. When the container is removed, everything written inside it is gone. This is by design—it makes containers disposable and reproducible. But real applications need persistence: a database must survive a restart, a log file must be available after the container stops, a configuration file must be shared with the…
A virtual machine is not the only way to build an LFCS practice lab. Containers offer a lighter alternative: faster to start, smaller on disk, and easier to reset. But containers are not virtual machines. They share the host kernel, they have no init system by default, and they cannot practice kernel-level tasks like RAID,…
The LFCS is a performance-based exam. You cannot pass it by reading. The tasks require you to sit at a terminal and perform actions on a live system: create users, configure services, manage storage, troubleshoot networks. A virtual machine lab is the mechanism by which the knowledge becomes skill. This chapter walks through building that…
The LFCS is a performance-based exam. You cannot pass it by reading. The tasks require you to sit at a terminal and perform actions on a live system: create users, configure services, manage storage, troubleshoot networks. A practice lab is not optional—it is the mechanism by which the knowledge becomes skill. This chapter covers the…
The LFCS is a performance-based exam. You sit at a live terminal, on a real Linux system, and perform tasks. There is no list of answers to choose from. The system either matches the required state or it does not. Understanding how the exam is structured, how the domains are weighted, and how scoring works…
The Linux Foundation Certified System Administrator (LFCS) is a performance-based certification that validates practical Linux system administration skills. Unlike multiple-choice exams that test recognition, the LFCS places you in a live terminal environment and asks you to solve real problems. There is no partial credit for recognizing a command—you either configure the system correctly or…