A Hypervisor is a software layer that creates, manages, and runs virtual machines (VMs) by allocating physical hardware resources to them.
It acts as a bridge between:
Without a hypervisor, virtualization cannot exist.
👉 Hypervisor = “Virtual Machine Manager”
It controls:
There are two main architectures:
Architecture:
Hardware → Hypervisor → Virtual Machines
Architecture:
Hardware → Host OS → Hypervisor → Virtual Machines
Divides CPU, RAM, and storage among VMs.
Ensures one VM does not interfere with another.
Creates, starts, stops, and deletes VMs.
Uses techniques like:
Decides which VM gets CPU time.
Creates:
Hypervisor ensures:
If hypervisor is compromised → Entire system at risk.
| Feature | Type 1 | Type 2 |
| Installation | Direct on hardware | On Host OS |
| Performance | High | Medium |
| Security | More secure | Depends on OS |
| Use Case | Enterprise | Testing/Labs |
Think of:
Manager assigns rooms and resources to guests.
Cloud providers use hypervisors to:
Without hypervisor → No cloud services.
Hypervisor is important because it:
A physical server with:
Hypervisor divides resources into:
All VMs run independently.
Answer:
A hypervisor is a software layer that creates and manages virtual machines by allocating hardware resources like CPU, RAM, storage, and network to each VM.
Answer:
Two types:
1️⃣ Type 1 (Bare-Metal) – Runs directly on hardware
Example: VMware ESXi, Hyper-V, KVM
2️⃣ Type 2 (Hosted) – Runs on top of an operating system
Example: VirtualBox, VMware Workstation
Virtual Hardware refers to software-defined hardware components that are created by the hypervisor and assigned to a virtual machine (VM).
Although they appear as real hardware inside the VM, they are actually logical representations of physical resources.
👉 Virtual Hardware = Fake hardware created by software.
Inside a VM, you will see:
But physically, these are coming from the host machine.
Without virtual hardware:
Virtual hardware provides a controlled interface between VM and physical hardware.
A virtual processor assigned to a VM.
Example:
VM thinks it has 2 processors.
Memory allocated to VM from physical RAM.
Example:
VM sees 8GB as its real memory.
A file stored on host that acts as hard drive for VM.
Formats:
Virtual network adapter inside VM.
Modes:
VM also contains:
Used during VM boot process.
Used for:
Flow:
Virtual Hardware → Hypervisor → Physical Hardware
Hypervisor translates:
| Feature | Physical Hardware | Virtual Hardware |
| CPU | Real processor | Software-defined |
| RAM | Physical memory | Allocated memory |
| Disk | Physical drive | File-based disk |
| Network | Physical NIC | Virtual NIC |
✅ Flexible allocation
✅ Easy resizing (increase RAM/CPU)
✅ Easy backup (copy disk file)
✅ Snapshot support
✅ Cost efficient
❌ Performance slightly lower
❌ Depends on host resources
❌ Resource contention possible
A company has:
Creates:
| VM | vCPU | vRAM |
| VM1 | 4 | 16GB |
| VM2 | 4 | 16GB |
| VM3 | 8 | 32GB |
| VM4 | 4 | 16GB |
All share the same physical hardware but work independently.
Answer:
Virtual hardware is software-defined hardware created by a hypervisor and assigned to a virtual machine, allowing the VM to run like a physical computer.
Answer:
Answer:
A vCPU is a virtual processor assigned to a virtual machine that is mapped to the physical CPU cores of the host system.
