Containerization is a method of operating-system-level virtualization used to deploy and run applications in isolated spaces called containers. A container packages an application's code along with all its necessary dependencies, such as libraries, system tools, and runtime environments. This creates a single, lightweight, executable software package that is portable and can run consistently and reliably across various computing environments, from a local machine to a cloud infrastructure.

A. Package manager: A package manager installs and manages software packages and their dependencies for a specific operating system or programming language, not for cross-environment portability.

B. Code repository: A code repository is a storage location for managing and tracking changes to source code (e.g., Git); it does not package the application for execution.

C. Virtual machine: A virtual machine emulates an entire computer system, including a full guest operating system, making it much more resource-intensive than just packaging an application and its libraries.

1. Docker Inc. (Official Vendor Documentation). "What is a Container?". Docker Resources. Accessed October 2023. The documentation states

"A container is a standard unit of software that packages up code and all its dependencies so the application runs quickly and reliably from one computing environment to another."

2. Bernstein

D. (2014). "Containers and Cloud: From LXC to Docker to Kubernetes." IEEE Cloud Computing

1(3)

pp. 81-84. DOI: 10.1109/MCC.2014.51. This paper (Section: "What Is a Container?") describes containers as a technology that packages an application with its runtime dependencies

enabling it to run on any infrastructure.

3. University of California

Berkeley. "CS 162: Operating Systems and Systems Programming

" Lecture 22: Virtual Machines. The course materials often contrast VMs with containers

defining containers as a lightweight alternative that bundles the application and its dependencies to run on a shared host OS kernel

ensuring environmental consistency.