Virtualization is a core concept and technology powering global digital infrastructures. From virtual desktops to virtual machines on the cloud, virtualization maximizes physical hardware and software resources for the benefit of many industries.
Paravirtualization, a type of virtualization that many experts consider the most enhanced and advanced form of the tech, is growing in popularity. Let’s look into what the tech is, how it works, its challenges and strengths, and how it differentiates from other types of virtualization.
What is paravirtualization?
Paravirtualization is a type of virtualization where guest operating systems (OSs) — those installed on a virtual machine (VM) — are modified to enable the guest OS and the hypervisor to communicate and manage resources, creating a collaboration environment. This collaboration between the guest OS and the hypervisor can improve performance and efficiency.
VMs in paravirtualization are therefore not fully isolated, because they share resources and can modify their usage according to their needs. Contrary to full virtualization where resources assigned to a VM by a hypervisor are fixed and simulate a real physical device, in paravirtualization the allocated resources are not fixed but flexible.
Paravirtualization hypervisors are more advanced versions of full virtualization hypervisors because they do not just assign resources and manage them, but can also perform certain services on behalf of the guest OS.
How does paravirtualization work?
Paravirtualization is possible thanks to a modified OS which is designed to communicate directly with the hypervisor that manages the VM. This communication is done through hypercalls — instructions that the guest OS uses to request services from the hypervisor.
You can imagine the hypervisor acting as the middleman between the guest OS and the physical hardware which will be assigned to the VM where the guest OS operates. The hypervisor as a software layer sits between resources and the guest OS.
Just like in full virtualization, the hypervisor is responsible for the management of the physical resources of a data center, server, or device, and allocates them to a guest OS. But in paravirtualization, because the OS can communicate with the hypervisor via hypercalls, it can request resources “on demand.”
This flexible approach allows the guest OS to scale up or down depending on need and better manage resources while increasing performance and security. The guest OS can even ask the hypervisor to execute certain processes or services on its behalf, alleviating its burden of executing tasks that are resource and time-consuming and therefore increasing its performance.
For example, a guest OS might make a hypercall to the hypervisor requesting access to more memory to perform a specific task. The hypervisor receives the request, but instead of assigning more memory to the guest OS, it performs the operation on behalf of the OS.
What is full virtualization?
Full virtualization is commonly referred to simply as virtualization. In full virtualization, a user creates a VM using a hypervisor and allocates and assigns all the resources — hardware and software — to the VM. Contrary to paravirtualization, the guest OS is not modified to collaborate with the hypervisor.
In full virtualization, each VM is completely isolated from other VMs and is fully independent. VMs in this model of virtualization do not share resources unless configured to do so. This makes full virtualization highly portable and isolated. However, it is not considered the top performing virtualization structure.
What is partial virtualization?
In partial virtualization, the hypervisor does not emulate the entire hardware environment for each VM. Instead, it provides a partial emulation of the hardware, such as the CPU and memory. This allows the VMs to run directly on the physical hardware, which can improve performance.
Partial virtualization environments tend to perform better than fully virtualized environments; however, they are not as isolated, secure, or portable.
Paravirtualization vs. full vs. partial virtualization: Quick chart
Let’s take a quick look at the main differences between paravirtualization, full virtualization, and partial virtualization with a focus on guest OS modifications, isolation, performance, security strengths and more.
|Requires guest OS modification
|Not fully isolated
|Complete logical isolation
|Not fully isolated
Ideal uses of paravirtualization
Paravirtualization’s potential and flexibility make it an ideal technology that can be applied to many industries and use cases.
Cloud computing: Google, IBM, Amazon, Microsoft and other top vendors all leverage paravirtualization to better maximize their cloud computing environments, drive efficiencies, and improve scalability and performance. It is thanks to this model of virtualization that hundreds of millions of users can seamlessly access the cloud and its wide range of services and features.
IT and mobile: Large IT and mobile industry companies that have intense workloads and high-performance demands are known to deploy paravirtualization environments to improve operations, reliability, and resilience.
High-performance computing industries: From defense to pharmaceutical and other industries, organizations that need to operate high-performance computing environments usually look into paravirtualization to reduce the overhead of the hypervisor in their virtual infrastructures.
Legacy systems: With paravirtualization industries and companies can run legacy systems on modern hardware without having to modify the legacy systems themselves.
Research and development: Paravirtualization can be used in research and development environments to experiment with new OS and applications without having to modify the underlying hardware.
Security and privacy: Paravirtualization is also used to enhance cybersecurity and privacy, especially in issues related to disaster recovery solutions.
Software development: Paravirtualization provides DevSecOps teams with perfect digital environments to build, test, deploy and monitor their software, API, code, or apps.
Advantages of paravirtualization
Paravirtualization provides numerous advantages to organizations, including increased performance, adaptability, and security.
Paravirtualized guest OSs can perform better than fully virtualized systems because they do not need to rely on the hypervisor to emulate the hardware. Instead, they can communicate directly with the hypervisor to request services. This can reduce latency and improve overall performance.
However, it is important to note that performance will always depend on the proper settings, configuration and management.
Resourcing and scalability
Paravirtualized OS can also be used to maximize resources by sharing resources efficiently managed through a hypervisor. These characteristics can be used to power high-performance computing processes, scaling up or down when needed.
While paravirtualization does not offer full logical integration, it still provides a good level of isolation to enhance security. The hypervisor can monitor and control the guest OS’s access to hardware resources and this can help prevent malicious malware or requests from accessing unauthorized resources.
Paravirtualization challenges are mostly technical, requiring expertise to deploy and manage, as well as to navigate complex compatibility issues.
Deploying, managing, operating and monitoring paravirtualized guest OS requires advanced technical skills which happen to be in shortage in the current market. If not properly configured a paravirtualized OS will not perform well and can present risks.
Portability and compatibility
Additionally, because paravirtualization shares resources it is not as portable as other types of virtualization architectures. Modifying an OS for it to collaborate with the hypervisor can also be challenging for untrained professionals. Finally, not all guest OSs support paravirtualization and troubleshooting these environments can be tricky.
There are several reasons why top cloud providers and leading companies choose to use paravirtualization. While paravirtualization is not for everyone or every use case, it is a powerful virtualization technology that can offer a number of benefits, including improved performance, efficiency, scalability, security, and reduced overhead. Ultimately whether you choose to go with paravirtualization, full virtualization, or partial virtualization will depend on your organization’s particular needs, budget, and infrastructure.
Whichever type of virtualization you choose, you can’t go wrong with one of these top virtualization companies.