Hypervisor

Host Computer

Building My VM - Ubuntu

Backing Up Linux

Computer Hardware

Updating Operating System

Linux Command Line Interface (CLI) User Commands

Components of Virtual Machines

1. Host System:
   • This is your physical computer, which has its own operating system and hardware resources (CPU, RAM, disk space).
2. Hypervisor:
   • The hypervisor is the key component that enables virtualization. It manages the virtual machines and allocates resources from the host system to them. There are two main types:
     • Type 1 Hypervisor: Installed directly on the hardware. It’s more efficient because it doesn’t have to go through a host operating system. Examples: VMware ESXi, Microsoft Hyper-V.
     • Type 2 Hypervisor: Runs on top of a regular operating system. It’s often used for personal or small-scale applications. Examples: VMware Workstation, Oracle VirtualBox.
3. Virtual Machine:
   • Each VM is like a separate computer running on the host system. It has its own virtual CPU, memory, disk space, and network interfaces, which are all created and managed by the hypervisor.
   • The VM runs its own operating system (guest OS), which can be different from the host OS. For example, you might run Linux on a Windows host.

How Virtual Machines Work

1. Virtualization Layer:
   • The hypervisor creates a layer of abstraction between the physical hardware and the VM. This abstraction allows multiple VMs to share the same physical resources.
   • Each VM has its own virtual hardware, which includes a virtual CPU, virtual RAM, virtual hard drives, and virtual network interfaces.
2. Resource Allocation:
   • The hypervisor allocates portions of the host system’s resources to each VM. For example, if your host has 16 GB of RAM, you might allocate 4 GB to one VM and 8 GB to another, leaving the rest for the host and other VMs.
   • The hypervisor ensures that each VM has access to its allocated resources and manages these resources to avoid conflicts.
3. Isolation:
   • VMs are isolated from each other, meaning that problems in one VM (like a software crash or security breach) don’t directly affect others. This isolation is achieved through the virtualization layer and helps in managing different environments securely.
4. Snapshots and Cloning:
   • Hypervisors often provide features like snapshots (saving the state of a VM at a particular point in time) and cloning (creating copies of VMs). These features are useful for backup, testing, and development purposes.

Use Cases

1. Testing and Development:
   • Developers use VMs to test software in different operating systems and configurations without needing multiple physical machines.
2. Server Consolidation:
   • Businesses can run multiple virtual servers on a single physical server, which helps in optimizing hardware usage and reducing costs.
3. Isolation:
   • VMs can isolate applications or services to improve security and stability. For instance, you can run a web server in one VM and a database server in another.