Which statement best captures the practical difference between virtualization and containerization?

• A. Virtualization and containerization are functionally identical in resource usage.
• B. Containerization runs multiple OS instances via virtual machines; virtualization uses containers that share the host OS kernel.
• C. Virtualization uses containers that share the host OS kernel; containerization runs full OS instances.
• D. Containerization runs containers that share the host OS kernel; virtualization runs multiple OS instances via virtual machines.

Answer: (D)

The practical difference is how isolation and resources are handled. In containerization, you run containers that share the host operating system's kernel, with each container providing its own isolated user space but not a separate kernel. In virtualization, you run multiple OS instances on top of a hypervisor, so every virtual machine has its own complete OS kernel and user space.

This explains why containers are lightweight and fast to start, delivering high density, while virtual machines are heavier but offer stronger isolation boundaries and can run different operating systems. The statement that best captures the difference is that containerization runs containers that share the host OS kernel, whereas virtualization runs multiple OS instances via virtual machines.

The other ideas misstate the setup: virtualization does not use containers, and containers do not run a full OS kernel per container. Additionally, resource usage is not identical—the overhead and isolation characteristics differ because of shared versus separate kernels.