Which term describes the practice of running multiple workloads in isolated environments on a single host, sharing the host's OS kernel?

• A. Containerization
• B. Virtualization
• C. Emulation
• D. Sandboxing

Answer: (A)

Containerization isolates multiple workloads on a single host by sharing the host's OS kernel. Each container runs its own isolated user space with its application and dependencies, but all containers use the host’s kernel, enabling lightweight and fast startup. This approach relies on kernel features like namespaces for process and filesystem isolation and cgroups for resource control, giving separation without the overhead of separate operating systems.

This differs from virtualization, where each workload runs in its own virtual machine with a separate guest OS and kernel, which adds more overhead. Emulation imitates hardware or another architecture and isn’t about running multiple isolated workloads on a single host with a shared kernel. Sandboxing provides restricted permissions for a single process, but containerization offers portable, consistent environments across different hosts.