Basics of Virtualization, Hypervisors, VMs, and Containers.

What is virtualization?

Software abstraction of hardware allowing multiple OSs to run on one machine.

What is a hypervisor?

The software layer that creates and manages virtual machines.

Difference between Type 1 and Type 2 hypervisors?

Type 1 runs directly on hardware; Type 2 runs on top of an existing OS.

Give examples of Type 1 hypervisors.

VMware ESXi, Microsoft Hyper-V, KVM, Citrix XenServer.

Give examples of Type 2 hypervisors.

VirtualBox, VMware Workstation, VMware Fusion, Parallels Desktop.

What are the main benefits of virtualization?

Better utilization, lower energy use, scalability, isolation, cost savings.

What is a virtual machine (VM)?

A full OS emulation with its own kernel, binaries, and applications.

What is a container?

Lightweight OS-level virtualization sharing the host kernel.

Key difference between VMs and containers?

VMs have full OS isolation; containers share the OS but start faster and use fewer resources.

Why are containers faster than VMs?

They skip the full OS boot process and share the host kernel.

Which tool is the industry standard for containers?

Docker.

What is Kubernetes used for?

Orchestration — managing, scaling, and automating containerized applications.

What is the typical boot time difference between VMs and containers?

VMs: minutes; Containers: seconds.

Which virtualization technologies power cloud providers like AWS and GCP?

KVM (Kernel-based Virtual Machine).

How does Netflix use containers?

Runs thousands of Docker containers orchestrated by Kubernetes for microservices.