Virtualization Fundamentals (Hypervisor)
Virtualization is a technology that allows multiple virtual machines (VMs) to run on a single physical machine. This is made possible by a software layer called a hypervisor, which enables the sharing of the physical machine's resources among the virtual machines.
Key Concepts
- Virtual Machine (VM)
- Hypervisor
- Type 1 Hypervisor
- Type 2 Hypervisor
- Virtualization Benefits
Virtual Machine (VM)
A virtual machine is a software-based emulation of a physical computer. Each VM runs its own operating system and applications, as if it were a separate physical machine. VMs are isolated from each other, ensuring that issues in one VM do not affect others.
Example: A server hosting multiple websites can run each website on a separate VM, ensuring that a crash in one website does not bring down the entire server.
Hypervisor
A hypervisor, also known as a virtual machine monitor (VMM), is the software that creates and manages virtual machines. It allocates the physical machine's resources (CPU, memory, storage, etc.) to the VMs and ensures that they operate independently and securely.
Example: VMware ESXi and Microsoft Hyper-V are examples of hypervisors that manage multiple VMs on a single physical server.
Type 1 Hypervisor
A Type 1 hypervisor, also known as a bare-metal hypervisor, runs directly on the physical hardware. It manages the VMs without the need for a host operating system, making it more efficient and secure.
Example: VMware ESXi and Microsoft Hyper-V are Type 1 hypervisors commonly used in data centers and enterprise environments.
Type 2 Hypervisor
A Type 2 hypervisor, also known as a hosted hypervisor, runs on top of a host operating system. It relies on the host OS for resource management, which can introduce some performance overhead.
Example: VMware Workstation and Oracle VirtualBox are Type 2 hypervisors often used for desktop virtualization and development purposes.
Virtualization Benefits
Virtualization offers several benefits, including:
- Resource Efficiency: Multiple VMs can share a single physical machine's resources, reducing hardware costs and energy consumption.
- Flexibility: VMs can be easily created, moved, and cloned, allowing for rapid deployment and scaling of applications.
- Isolation: Each VM operates independently, ensuring that issues in one VM do not affect others, enhancing security and stability.
- Disaster Recovery: VMs can be backed up and restored quickly, facilitating efficient disaster recovery processes.
Example: A company can use virtualization to consolidate multiple physical servers into a single powerful server, reducing hardware costs and simplifying management.