Which virtualization method relies on a common host OS for each container?

Container-based virtualization indeed relies on a common host operating system for each container. This method packages applications and their dependencies into containers that share the host OS's kernel, allowing for efficient resource utilization and faster deployment. Each container runs in isolation but leverages the same underlying system resources of the host, which reduces overhead and improves performance.

In contrast to server-based virtualization, which requires a hypervisor to separate the virtual machines that may run different guest operating systems, container-based virtualization operates under a more lightweight model. Full virtualization also involves a hypervisor, allowing multiple operating systems to run concurrently on the same hardware but with greater resource allocation overhead compared to containers. Network virtualization focuses on separating network resources and doesn’t pertain to application execution environments like containers do.

Thus, the unique structure of container-based virtualization, relying on a singular host OS, makes it the correct answer for this question.