Lecture-06: Hypervisor in Cloud Computing (CC)

 Hypervisor in Cloud Computing

The hypervisor is a hardware virtualization technique that allows multiple guest operating systems (OS) to run on a single host system at the same time. A hypervisor is sometimes also called a virtual machine manager (VMM). 

 

Key Functions of Hypervisors

Hypervisors are essential for managing virtual environments effectively. They allocate resources, ensure secure isolation between virtual machines, monitor system performance, and support seamless migration of virtual machines. These functions enable efficient use of hardware and improve system reliability in virtualized infrastructures.

Resource Allocation: Hypervisors play a crucial role in distributing CPU, memory, and storage resources among multiple virtual machines. They manage how these resources are allocated to ensure optimal performance for each VM, avoiding resource conflicts and maximizing hardware efficiency.

Isolation: A key function of hypervisors is to ensure that each virtual machine operates in a secure, isolated environment. This isolation prevents one VM from interfering with the operations, data, or security of another, even though they share the same physical hardware.

Monitoring: Hypervisors continuously track the performance and resource usage of each virtual machine. This monitoring helps in identifying potential issues, optimizing resource allocation, and maintaining the overall health of the virtual environment.

Migration: Hypervisors enable the seamless transfer of virtual machines from one physical server to another with minimal downtime. This process, known as live migration, is essential for load balancing, hardware maintenance, and disaster recovery without interrupting the services running on the VMs.

Types of Hypervisors

 

1.    Type 1 Hypervisor (Bare-Metal Hypervisor):

Ø It is known to a "Native Hypervisor" or "Bare metal hypervisor" or "Bare metal hypervisor".

Ø The hypervisor runs directly on the underlying host system.

Ø It has direct access to hardware resources.

Ø  It does not require any base server operating system.

Ø They are commonly used in enterprise environments due to their high performance and efficiency.

Ø Example: VMware ESXi, Microsoft Hyper-V, Xen Server etc.

Advantages:

• High performance and efficiency.
• Better security due to minimal software layers.
• Direct access to hardware resources.

Disadvantages:

• Complex to set up and manage.
• Requires dedicated hardware.

                                                    
                                                  Figure: Hypervisor 1

2.    Type 2 Hypervisor (Hosted Hypervisor):

Ø It is also known as 'Hosted Hypervisor".

Ø A Host operating system runs on the underlying host system.

Ø Such kind of hypervisors doesn’t run directly over the underlying hardware rather they run as an application in a Host system (physical machine). Basically, the software is installed on an operating system. Hypervisor asks the operating system to make hardware calls.

Ø The type-2 hypervisor is very useful for engineers, and security analysts (for checking malware, or malicious source code and newly developed applications).

Ø Example: VMware Workstation, Oracle VirtualBox, Parallels Desktop, etc.

Advantages:

• Easy to install and use.
• Suitable for testing and development environments.
• Does not require dedicated hardware.

Disadvantages:

• Performance overhead due to the additional OS layer.
• Less secure compared to Type 1 hypervisors.

                                             Figure: Hypervisor 2

Feature	Type 1 Hypervisor (Bare-Metal)	Type 2 Hypervisor (Hosted)
Definition	Runs directly on physical hardware	Runs on top of a host operating system
Performance	Higher performance (closer to hardware)	Slightly lower performance (due to host OS overhead)
Use Case	Data centers, cloud providers, servers	Development, testing, desktop virtualization
Examples	VMware ESXi, Microsoft Hyper-V, Xen, KVM	Oracle VirtualBox, VMware Workstation, Parallels
Security	More secure (fewer layers)	More vulnerable (depends on host OS security)

Hypervisors in Cloud Platforms

In cloud computing, most cloud providers use Type 1 hypervisors because of      their efficiency, scalability, and security:

• AWS: Uses a customized version of the Xen hypervisor and Nitro Hypervisor (based on KVM).
• Microsoft Azure: Uses Hyper-V (Type 1).
• Google Cloud Platform (GCP): Uses KVM (Type 1).

Role of Hypervisors in Cloud Computing:

Hypervisors play a vital role in cloud computing by enabling:

Multi-Tenancy: Hypervisors enable multiple users to securely share the same physical infrastructure by creating isolated virtual environments. Each user’s data and applications operate independently within these virtual machines, ensuring privacy and security even on shared hardware.

Scalability: Hypervisors facilitate the rapid addition or removal of virtual machines based on demand. This dynamic scalability allows businesses to efficiently adjust their computing resources, supporting varying workloads without requiring physical hardware changes.

Resource Efficiency: By optimizing the allocation of hardware resources such as CPU, memory, and storage, hypervisors maximize resource utilization. This efficiency reduces costs and minimizes hardware wastage, allowing multiple virtual environments to operate seamlessly on the same physical system.

Disaster Recovery: Hypervisors support robust disaster recovery mechanisms by enabling quick backups, snapshots, and migrations of virtual machines. In case of hardware failure or data loss, virtual machines can be restored or moved to other servers with minimal downtime, ensuring business continuity.