What is a Type 3 hypervisor?

A type 3 hypervisor, also known as a hosted hypervisor, runs on top of a traditional operating system (OS) such as Windows or Linux. Unlike type 1 hypervisors that run directly on the system hardware, type 3 hypervisors rely on the underlying OS for resource management and hardware access.

What is a Type 3 hypervisor?

 

Key characteristics of a type 3 hypervisor:

  • Runs as an application on top of the OS rather than directly on hardware
  • Depends on the OS for resource management and hardware access
  • Generally easier to install and configure than type 1 hypervisors
  • Offer greater hardware support through the OS drivers
  • Examples include VMware Workstation, VirtualBox, Parallels Desktop

How does a type 3 hypervisor work?

A type 3 hypervisor serves as a host for virtual machines (VMs), allowing multiple VMs with different guest operating systems to run on a single physical machine. It works by abstracting and partitioning system resources from the underlying OS to allocate to each VM.

Key functions of a type 3 hypervisor:

  • CPU virtualization – Makes a single CPU appear as multiple virtual CPUs for assignment to VMs. Uses techniques like binary translation and paravirtualization.
  • Memory virtualization – Creates a memory pool from the OS resources to distribute memory across VMs. Uses memory overcommitment for efficiency.
  • I/O virtualization – Maps virtual devices in VMs to actual resources of the physical system.
  • Security isolation – Separates VMs in software containers with private system resources allocated per VM.

So while the guest VMs interact with virtualized platform resources, the hypervisor coordinates resource access to the actual hardware through the OS drivers and manages execution using CPU scheduling.

Advantages of a type 3 hypervisor

Easier installation

Type 3 hypervisors install just like any other software application on top of the OS. This makes them easier to implement compared to type 1 hypervisors that require dedicated installation.

Better hardware support

Since type 3 hypervisors leverage the mature and native device drivers in the host OS, they generally provide better hardware support for different components and peripheral devices.

Portability

Hosted hypervisors and the associated VMs can be readily moved between compatible OS installations on different hardware systems.

Support for heterogeneous environments

A major advantage of type 3 hypervisors is their ability to run a variety of guest OSs on the same physical system, enabling heterogeneous application environments.

Development and testing

The simplified virtualized environment enabled by hosted hypervisors facilitates application development, testing and debugging processes.

Disadvantages of a type 3 hypervisor

Reduced performance

The additional software layer introduces processing overhead that affects VM performance. Direct hardware access with type 1 hypervisors allow better performance.

Limited scalability

The scalability in a type 3 hypervisor setup is constrained because system resources are first managed by the host OS before allocation to VMs.

Stability is tied to the OS

Any crashes in the host OS can bring down all the guest VMs running on it. So the stability of the entire virtualization environment depends on the underlying OS.

Security risks

The threat surface is increased since both the hypervisor and host OS need to be secured against attacks.

Type 3 hypervisor use cases

Development and testing environments

Developers can create multiple VMs with different configurations for application development, testing, debugging etc. without disrupting production environments.

Server consolidation

Type 3 hypervisors help consolidate multiple server workloads like web, database, analytics onto a single server system by hosting the workloads in separate VMs.

Desktop virtualization

Hosted hypervisors allow desktop users to run multiple operating systems on a single physical desktop or laptop. For example, accessing Linux and Windows VMs on a Mac system.

Disaster recovery

VMs replicated across multiple sites using type 3 hypervisors provide a cost-effective disaster recovery solution for SMBs. If one site goes down, the VMs can be failed over to another site.

Popular type 3 hypervisors

VMware Workstation

Pioneer hosted hypervisor used extensively for development, testing and interoperability. Available for Windows and Linux host systems.

Oracle VM VirtualBox

Open source, cross platform solution ideal for server consolidation. Features like live migration and intuitive management.

Microsoft Hyper-V

Hypervisor built into Windows server and client SKUs. Enables Windows sandboxing for added security. Tightly integrated with the OS.

Parallels Desktop

Leading hypervisor for Mac users. Seamlessly runs Windows on Mac hardware without rebooting. Supports graphics intensive applications.

QEMU

Open source type 2 hypervisor supporting cross architecture virtualization like ARM on x86 systems. Features hardware emulation for I/O virtualization.

Type 3 vs. Type 1 vs. Type 2 hypervisors

Hypervisor Type Host Computer Runs On Performance Use Cases Examples
Type 1 (Bare Metal) Dedicated server Directly on host hardware High Data centers, enterprise apps VMware ESXi, Microsoft Hyper-V, Citrix XenServer
Type 2 (Hosted) Shared server, desktop or laptop Within host OS environment Moderate Testing, development, desktop apps VMware Workstation, Oracle VM VirtualBox
Type 3 (Hybrid) Shared server, desktop or laptop Partially on hardware and host OS Mixed General purpose virtualization Red Hat KVM, Microsoft Hyper-V

So in summary:

  • Type 1 runs directly on hardware
  • Type 2 runs as an application in a host OS
  • Type 3 has a split-mode hybrid execution model

The hypervisor type depends on the use case – single vs. multi-tenancy, performance needs and hardware consolidation requirements.

Key takeaway

Type 3 hypervisors run on top of a host operating system and provide virtualization by partitioning system resources from the host OS to assign to guest virtual machines. This hosted architecture makes type 3 hypervisors easy to install and configure, while providing the ability to efficiently consolidate workloads from multiple systems and users onto a single server or desktop system. Leading use cases are development, testing, desktop applications and basic server consolidation.

Conclusion

A type 3 hypervisor creates virtual machines by leveraging hardware resources and drivers from an underlying host operating system such as Windows or Linux. This hosted architecture distinguishes type 3 hypervisors from bare-metal type 1 solutions and makes them easier to deploy, move between compatible systems and support heterogeneous environments. While they offer advantages for non-performance sensitive use cases, the additional software layer does introduce modest processing overhead that affects VM performance compared to type 1 hypervisors. Overall, type 3 represents a flexible and cost-effective virtualization option suitable for labs, desktops and basic production workloads.

Frequently Asked Questions

Q: Can you run OS X on a Type 3 hypervisor?
A: Yes, type 3 hypervisors like VMware Workstation and Parallels Desktop for Mac allow you to run OS X guest virtual machines on Windows or Linux host operating systems.

Q: Do you need virtualization support in the CPU for Type 3 hypervisors?
A: No, CPU virtualization support is not mandatory for type 3 hypervisors since they run on top of the host OS that manages processor resources.

Q: Is VMware Workstation a Type 1 or Type 2 hypervisor?
A: VMware Workstation is an example of a Type 2 or hosted hypervisor that runs within the host machine’s OS rather than directly on hardware.

Q: Which hypervisor type has the best performance?
A: Type 1 or bare-metal hypervisors that run directly on host hardware offer the best performance among hypervisor types.

Q: Can you use Nested Virtualization on a Type 3 hypervisor?
A: Yes, nested virtualization allows you to run hypervisors as virtual machines on top of another hypervisor. You can deploy nested virtualization solutions with Type 3 hypervisors.

Q: Is Hyper-V a Type 1 or Type 2 hypervisor?
A: Microsoft Hyper-V can operate as both type 1 (Hyper-V Server) and type 2 (Hyper-V Client) depending on the use case requirements.

Q: What is virtualization passthrough?
A: Virtualization passthrough or direct assignment allows VMs to directly access certain hardware components for improved device performance and efficiency.

Q: How is memory managed in Type 3 hypervisors?
A: Type 3 hypervisors partition and allocate memory resources from the host OS to supply to the individual guest VMs running on them.

Q: Can you run Docker containers on Type 3 hypervisors?
A: Yes, you can deploy and run Docker containers as guest virtual machines using hosted hypervisors like VMware Workstation or VirtualBox.

Q: What are Para virtualized devices?
A: Para virtualized devices are optimized virtual devices designed specifically for increased performance in virtual environments instead of emulating real hardware.

Q: How do Type 3 hypervisors provide security isolation?
A: Security isolation is achieved by hosting each VM within its own isolated container partitioned using software from the underlying host operating system resources.

Q: What is memory over commitment in hypervisors?
A: Memory over commitment allows hypervisors to allocate more memory resources cumulatively across VMs than available on the physical host system. This helps improve memory utilization efficiency.

Q: Can Microsoft Office run on a Type 3 hypervisor?
A: Yes, Microsoft Office and everyday desktop applications can run within guest virtual machines on top of both Type 2 and Type 3 hosted hypervisors.

Q: Do Type 3 hypervisors support live migration of VMs?
A: Some Type 3 hypervisors like Oracle VirtualBox support live migration of guest VMs from one host system to another compatible host with no downtime.

Q: Can you play high-end video games in VMs on Type 3 hypervisors?
A: Type 3 hypervisors may struggle with high-end 3D games due to limited video acceleration support for guest VMs. Type 1 hypervisors would be better suited for this.

Q: What host operating systems can run Type 3 hypervisors?
A: All the major operating systems including Windows, Linux, Mac OS X and Solaris can host Type 3 hypervisors like VMware Workstation as an application.

 

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