Appendix C — Glossary & Acronyms

ARM: Advanced RISC Machine. A CPU architecture used by many mobile devices, single-board computers, and newer Macs. Compatibility can differ from x86_64 when building RHCSA lab environments.
CLI: Command-line interface. A text-based interface for running commands, managing files, and administering Linux systems.
Downstream: A project or distribution that receives, integrates, and stabilizes software from an upstream source.
Exam Attempt: One use of exam eligibility to sit for a certification exam.
Exam Voucher: A purchased authorization to schedule and take a certification exam within its validity period.
EX200: The exam code for the Red Hat Certified System Administrator exam.
Fedora: A community Linux distribution sponsored by Red Hat and upstream of Red Hat Enterprise Linux.
Hypervisor: Software that creates, runs, and manages virtual machines.
KVM: Kernel-based Virtual Machine. The Linux kernel virtualization technology used to run hardware-assisted virtual machines.
Lab Environment: A controlled practice environment used to safely learn, test, and repeat system administration tasks.
libvirt: A virtualization management API and toolkit commonly used on Linux to manage KVM/QEMU virtual machines.
Linux Distribution: A complete Linux operating system assembled from the Linux kernel, userland tools, package repositories, and distribution-specific defaults. Often shortened to “distro.”
QEMU: A machine emulator and virtualizer often used with KVM to run virtual machines.
Red Hat Developer Account: A Red Hat account used to access developer resources, subscriptions, downloads, and certification services.
Retake: A subsequent exam attempt after a failed or missed attempt, if included with the exam product or purchased separately.
RHCE: Red Hat Certified Engineer. Red Hat’s next certification beyond the RHCSA, focused on automation with Ansible. Earned by passing the EX294 exam; requires an active RHCSA as a prerequisite.
RHCSA: Red Hat Certified System Administrator. Red Hat’s entry-level system administration certification, earned by passing the EX200 performance-based exam. The focus of this book.
RHEL: Red Hat Enterprise Linux. Red Hat’s enterprise Linux distribution and the operating system used for the RHCSA exam.
RHLS: Red Hat Learning Subscription. Red Hat’s annual training subscription, bundling access to official courses, hands-on labs, and exam vouchers. Sold in tiers (Single Course, Standard, Premium) at varying prices and lab-hour / exam-attempt allowances.
RHSM: Red Hat Subscription Management. The tooling and service used to register RHEL systems and attach subscriptions.
Shell: The command interpreter that reads and runs commands in a terminal. Bash is the default interactive shell on many Linux systems.
Subscription: Red Hat’s entitlement mechanism for access to RHEL repositories, updates, and support-backed content.
Terminal: A program that provides access to a shell session.
Upstream: A project or distribution where software changes originate before flowing into downstream projects.
Vagrant: A tool for defining and managing reproducible virtual machine environments from a project configuration.
Vagrant Box: A packaged base image used by Vagrant to create virtual machines.
Vagrant Plugin: An extension that adds capabilities to Vagrant, such as libvirt support or Red Hat registration.
Vagrant Provider: The virtualization backend Vagrant uses to run a VM, such as libvirt or VirtualBox.
Vagrantfile: The Ruby-based configuration file Vagrant uses to define virtual machines, providers, networking, and provisioning behavior.
Virtual Machine: A software-defined computer running as a guest on a host system. Commonly abbreviated as VM.
VirtualBox: Oracle’s desktop virtualization platform and one of Vagrant’s supported providers.
Virtualization Extensions: CPU features such as Intel VT-x or AMD-V that provide hardware support for virtualization.
VM: Virtual machine. A software-defined computer running as a guest on a host system.
WSL: Windows Subsystem for Linux. A Windows feature that provides a Linux user space and command-line environment on Windows.
x86_64: The 64-bit Intel/AMD CPU architecture commonly used for RHEL systems and RHCSA lab virtual machines.