Problem Statement
What is nested virtualisation and what challenges does it introduce?
Explanation
Nested virtualisation occurs when a virtual machine itself hosts another virtualisation layer (a VM inside a VM). This can be useful for development, testing or cloud provider architectures. Challenges include increased overhead, more complex hardware and hypervisor support (CPU extensions like VT-x/AMD-V must be forwarded), more layers of translation (guest to host), greater resource contention and reduced performance. Discussing real-world scenarios or trade-offs strengthens your answer in interviews.
