Paravirtualization in cloud computing (PV) | Best of cloud computing – 2021

Another approach to virtualization is to modify the source code of the guest operating system. If we can do that, not only can we avoid problematic instructions, as I mentioned earlier with full virtualization, but we can also include optimizations. For instance.

Letting the guest operating system, see real hardware resources, underneath the hypervisor, access to real hardware resources and also being able to employ tricks such as page coloring. Exploiting the characteristics of the underlying hardware.

It is important to note, however, that so far as the applications are concerned, nothing is changed about the operating system because the interfaces that the applications see is exactly the interfaces provided by.

Paravirtualization in cloud computing (PV)
Paravirtualization in cloud computing (PV)

Paravirtualization in cloud computing

In the operating system, if there is an application that is running on the window, it sees the same API. If the application is running on top of Linux, it sees exactly the same API as it would if this Linux operating system was running on native hardware.

In this sense, there’s no change to the applications themselves. But, the operating system has to be modified in order to account for the fact that it is not running on bare metal, but it is running as a guest of the hypervisor.

And this is why this technology is often referred to as. Paravirtualization, meaning it is not fully virtualized, but a part of it is modified to account for being a guest of the hypervisor.

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The Zen product family uses this paravirtualization approach. Now, this brings up an interesting question. I said that, in order to do this part visualization we have to modify the operating system, but how big is this modification?

A very different approach is to give up on the goal of running unmodified operating systems. Instead, the primary goal is to offer a virtualization solution that offers performance and avoids some of the overheads that may be associated with any of the complexities that are necessary to support unmodified guests.

In contrast to full virtualization, this is called paravirtualization. With paravirtualization, the guest OS is modified so that it now knows that it’s running in a virtualized environment on top of a hypervisor as opposed to on top of native physical resources.

A para-virtualized guest OS will not necessarily try to directly perform operations, which it knows they will fail. And instead, it will make explicit calls to the hypervisor to request the desired behavior. Or specifically, the desired hardware manipulations.

These calls to the hypervisor are called hypercars. And they behave in a way that’s similar to the way system calls behave in an operating system.

So the unprivileged guest OS here that’s modified will package all relevant information about its context, its current state. And it will specify the desired hypercall. And at that point, it will issue the hypercall and that will trap to the virtual machine monitor.

When the hypervisor completes the operation, control will be pass back to the virtual machine, to the guest, and any data, if appropriate, will be made available to it.

This approach of paravirtualization was originally adapted and popularized by the Xen hypervisor. This was a popular virtualization solution and originally was an open-source hypervisor that started as a research project at the University of Cambridge in the UK.

This was later commercialized as XenSource and XenSource is now owned by Citrix. But there still remains a lot of activity in the open-source Xen project, including at our own research group here.

One thing to note, however, is that the open-source Xen version as, and the Citrix Xen version have diverged perhaps substantially over time

One idea for this virtualization framework is what is called full virtualization, and in full virtualization, the idea is to leave the operating system pretty much untouched. So you can run the unchanged binary of the operating system on top of the hypervisor.

This is called full virtualization because the operating system is completely untouched. Nothing has been changed. Not even a single line of code is modified in these operating systems in order to run on the hypervisor simultaneously.

But we have to be a little bit clever to get this to work, however. Operating systems running on top of the hypervisor are run as user-level processes.

They’re not running at the same level of privilege as a Linux operating system that is running on bare metal. But if the operating system code is unchanged, it doesn’t know that it does not have the privilege for doing certain things that it would do normally on bare metal hardware.

In other words, when the operating system executes some privileged instructions, meaning they have to be, in a privileged mode or kernel mode to run on bare metal in order to execute those instructions.

Those instructions will create a trap that goes into the hypervisor and the hypervisor will then emulate the intended functionality of the operating system. And this is what is called the trap and emulate strategy.

Essentially, each operating system thinks it is running on bare metal. And therefore, it does exactly what it would have done on a bare-metal processor, meaning that it’ll try to execute certain privileged instructions thinking it has the right privilege.

But it does not have the right privilege, because it’s run as a user-level process on top of the hypervisor. And therefore, when they try to do something that requires.

A high level of privilege than the user level will result in a trap into the hypervisor, and the hypervisor will then emulate the intended functionality of the particular operating system. There are some thorny issues with this trap and emulate the strategy of full virtualization, and that is.

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In some architectures, some privilege instructions may fail silently. What that means is, you would think that the instruction actually succeeded, but it did not. And you may never know about it. And in order to get around this problem, in fully virtualized systems, the hypervisor will resort to a binary translation strategy, meaning.

It knows what are the things that might fail silently in the architecture. Look for those gotchas in each of these individual binaries of the unmodified guest operating systems. And through binary editing strategy.

They will ensure that those instructions are dealt with carefully so that if those instructions fail silently, the hypervisor can catch it and take the appropriate action. And this was a problem in early instances of Intel architecture.

Both Intel and AMD have since started adding virtualization support to the hardware so that such problems don’t exist anymore. But in the early going, when virtualization technology was experimented with, in the late ’90s and the early 2000s.

This was a problem that virtualization technology had to overcome in order to make sure that you can run operating systems as unchanged binaries on a fully virtualized hypervisor. Full virtualization is the technology that is employed in the VMWare system.

Paravirtualization in cloud computing

Paravirtualization and full virtualization in cloud computing

One idea for this virtualization framework is what is called full virtualization, and in full virtualization, the idea is to leave the operating system pretty much untouched.

So you can run the unchanged binary of the operating system on top of the hypervisor. This is called full virtualization because the operating system is completely untouched. Nothing has been changed.

Not even a single line of code is modified in these operating systems in order to run on the hypervisor simultaneously. But we have to be a little bit clever to get this to work, however.

Operating systems running on top of the hypervisor are run as user-level processes. They’re not running at the same level of privilege as a Linux operating system that is running on bare metal.

But if the operating system code is unchanged, it doesn’t know that it does not have the privilege for doing certain things that it would do normally on bare metal hardware.

In other words, when the operating system executes some privileged instructions, meaning they have to be, in a privileged mode or kernel mode to run on bare metal in order to execute those instructions.

Those instructions will create a trap that goes into the hypervisor and the hypervisor will then emulate the intended functionality of the operating system. And this is what is called the trap and emulate strategy. Essentially, each operating system thinks it is running on bare metal.

And therefore, it does exactly what it would have done on a bare-metal processor, meaning that it’ll try to execute certain privileged instructions thinking it has the right privilege. But it does not have the right privilege, because it’s run as a user-level process on top of the hypervisor.

And therefore, when they try to do something that requires. A high level of privilege than the user level, it will result in a trap into the hypervisor, and the hypervisor will then emulate the intended functionality of the particular operating system.

Emulate the strategy of full virtualization

There are some thorny issues with this trap and emulate the strategy of full virtualization, and that is. In some architectures, some privilege instructions may fail silently. What that means is, you would think that the instruction actually succeeded, but it did not. And you may never know about it.

And in order to get around this problem, in fully virtualized systems, the hypervisor will resort to a binary translation strategy, meaning. It knows what are the things that might fail silently in the architecture.

Look for those gotchas in each of these individual binaries of the unmodified guest operating systems. And through binary editing strategy.

They will ensure that those instructions are dealt with careful, so that if those instructions fail silently, the hypervisor can catch it and take the appropriate action. And this was a problem in early instances of Intel architecture. Both Intel and AMD have since started adding virtualization support to the hardware, so that such problems don’t exist any more.

But in the early going, when virtualization technology was experimented with, in the late 90’s and the early 2000s. This was a problem that virtualization technology had to overcome in order to make sure that you can run operating systems as unchanged binaries on a fully virtualized hypervisor. Full virtualization is the technology that is employed in the vmware system.

Another approach to virtualization is to modify the source code of the guest operating system. If we can do that, not only can we avoid problematic instructions, as I mentioned earlier with full virtualization, but we can also include optimizations. For instance.

Letting the guest operating system, see real hardware resources, underneath the hypervisor, access to real hardware resources and also being able to employ tricks such as page coloring. Exploiting the characteristics of the underlying hardware.

It is important to note, however that so far as the applications are concerned, nothing is changed about the operating system because the interfaces that the applications see is exactly the interfaces provided by.

The operating system, if there is an application that is running on the window, it sees the same API. If the application is running on top of Linux, it sees exactly the same API as it would if this Linux operating system was running on native hardware.

In this sense, there’s no change to the applications themselves. But, the operating system has to be modified in order to account for the fact that it is not running on bare metal, but it is running as a guest of the hypervisor.

And this is why this technology is often referred to as. Paravirtualization, meaning it is not fully virtualized, but a part of it is modified to account for being a guest of the hypervisor. The Zen product family uses this paravirtualization approach. Now this brings up an interesting question.

I said that, in order to do this paravisualization we have to modify the operating system, but how big is this modification?

A very different approach is to give up on the goal of running unmodified operating systems. Instead, the primary goal is to offer a virtualization solution that offers performance and avoids some of the overheads that may be associated with any of the complexities that are necessary to support unmodified guests.

In contrast to full virtualization, this is called paravirtualization. With paravirtualization, the guest OS is modified so that it now knows that it’s running in a virtualized environment on top of a hypervisor as opposed to on top of native physical resources.

A para-virtualized guest OS will not necessarily try to directly perform operations, which it knows that they will fail. And instead, it will make explicit calls to the hypervisor to request the desired behavior. Or specifically, the desired hardware manipulations.

These calls to the hypervisor are called hypercars. And they behave in a way that’s similar to the way system calls behave in an operating system. So the unprivileged guest OS here that’s modified will package all relevant information about its context, its current state. And it will specify the desired hypercall.

And at that point, it will issue the hypercall and that will trap to the virtual machine monitor. When the hypervisor completes the operation, control will be pass back to the virtual machine, to the guest, and any data, if appropriate, will be made available to it.

This approach of paravirtualization was originally adapted and popularized by the Xen hypervisor. This was a popular virtualization solution and originally was an open-source hypervisor that started as a research project at the University of Cambridge in the UK.

This was later commercialized as XenSource and XenSource is now owned by Citrix. But there still remains a lot of activity in the open-source Xen project, including at our own research group here.

One thing to note, however, is that the open-source Xen version as, and the Citrix Xen version have diverged perhaps substantially over time

What is cloud computing?

What is cloud computing ?

Cloud computing is the on-demand delivery of IT resources via the internet, with pay-as-you-go pricing. Instead of buying, owning and maintaining physical data centers and servers you can access technology services, such as computing power, storage and databases, on an as-needed basis from a cloud provider like Amazon Web Services.

Organizations of every type, size and industry are using the cloud for a wide variety of use cases, such as data backup, disaster recovery, email, virtual desktops, software development and testing, big data analytics, and customer-facing web applications.

For example, health care companies are using the cloud to develop more personalized treatments for patients. Financial services companies are using the cloud to power real-time fraud detection and prevention.

And video game makers are using the cloud to deliver online games to millions of players around the world. With cloud computing, your business can become more agile, reduce costs, instantly scale, and deploy globally in minutes.

Cloud computing gives you instant access to a broad range of technologies so you can innovate faster and build nearly anything you can imagine, from infrastructure services such as compute, storage and databases, to the internet of things, machine learning, data analytics, and much more.

You can deploy technology services in a matter of minutes and get from idea to implementation several orders of magnitude faster than before.

This gives you the freedom to experiment and test new ideas to differentiate customer experiences and transform your business, such as adding machine learning and intelligence to your applications in order to personalize experiences for your customers and improve their engagement.

You don’t need to make large, upfront investments in hardware and overpay for capacity you don’t use. Instead, you can trade capital expense for variable expense and only pay for IT as you consume it. With cloud computing, you access resources from the cloud in real-time as they’re needed.

You can scale these resources up and down to grow or shrink capacity instantly as your business needs change. Cloud computing also makes it easy to expand to new regions and deploy globally in minutes.

For example, Amazon Web Services has infrastructure all over the world so you’re able to deploy your application in multiple physical locations in just a few clicks. Putting applications in closer proximity to end users reduces latency and improves their experience.

No matter your location, size, or industry, the cloud frees you from managing infrastructure and data centers so you can focus on what matters most to your business.

Cloud computing basics. The advancement of technology and encompassing networks storage and processing power led to the epitome of computing. In this century it’s called cloud computing or commonly referred to as a cloud.

What is cloud computing? Cloud computing is a paradigm that allows on-demand network access to shared computing resources, a model for managing, storing, and processing data online via the Internet.

Some cloud computing characteristics include; On-demand service: You use it when you need it. Network access: Using the Internet as a medium. Shared resources: Resources are pulled together and used by multiple clients.

Scalability: Allows elasticity of resources. Three delivery models of cloud computing: SaaS, PaaS and IaaS. Cloud computing offers different services based on three delivery models.

When arranged in a pyramid form. They follow the order of SaaS, PaaS and IaaS. What is SaaS? SaaS or software as a service. It is a service that offers on-demand pay per use of application software to users.

Unlike licensed bought programs. This service is platform-independent and you don’t need to install the software on your PC. The cloud runs a single instance of the software and makes it available for multiple end-users.

This makes cloud computing cheap. All the computing resources responsible for delivering SaaS are entirely managed by the vendor.

This service is accessible via a web browser or lightweight client applications. Who use Saas – End customers are frequent users of SaaS.

Example product and services of SaaS. Popular SaaS providers offer the following products and services. The Google ecosystem such as Gmail, Google Docs, and Google Drive.

Microsoft Office 365, HR and helpdesk solutions and customer relationship management services such as Salesforce. Pros: Universally accessible from any platform.

No need to commute you can work from any place. Excellent for collaborative working. The vendor provides modest software tools.

Allows for multi-tenancy. Cons: Portability and browser issues. Internet performance may dictate overall performance. Compliance restrictions. What is PaaS? PaaS or platform-as-a-service.

This service is mainly a development environment and is made up of a programming language execution environment, an operating system a web server and a database.

All of this encapsulates the environment where users can build, compile and run their programs without worrying at the underlying infrastructure. In this model you manage data and the application resources. All other resources are managed by the vendor. Who uses PaaS? This is a domain for developers.

Example products and services of PaaS. Cloud providers have the following as the PaaS products and services: Amazon Web Services elastic Beanstalk, Google App Engine, Windows Azure, Heroku and force.com Pros: Cost-effective rapid development.

it’s scalable. The faster market for developers. Easy deployment of web applications. Private or public deployment is possible. Cons: Developers are limited to providers’ languages and tools. Migration issues such as the risk of vendor lock-in.

What is IaaS? IaaS or infrastructure-as-a-service this service offers the computing architecture and infrastructure that is it offers all computing resources but in a virtual environment so that multiple users can access them. These resources include data storage, virtualization, servers and networking. Most vendors are responsible for managing the above for resources.

If you will use this service you will be responsible for handling other resources such as applications, data, runtime and middleware Who use IaaS? IaaS is mainly for SysAdmin. Example products and services of IaaS include Amazon EC2, GoGrid and Rackspace.com Pros: The cloud provides the infrastructure. Enhanced scalability dynamic workloads are supported. IaaS is flexible.

Cons: Security issues. Network and service delays. Examples of companies that use cloud computing. Amazon’s AWS or Amazon Web Services. When it comes to companies using cloud computing, AWS takes the lead. This cloud computing company offers IaaS and PaaS services to its customers.

it’s popular for its Elastic Compute Cloud EC2. Among other services such as elastic beanstalk, Simple Storage Service (S3) and relational database service or RDS. Apart from the complete suite of cloud computing. It offers other cloud-related services including the internet of things (IoT), cloud security and mobile services.

iCloud: This cloud from Apple is majorly for Apple products and allows you to backup and store all your multimedia and other documents online. This content is then seamlessly integrated onto all your devices or apps. In case you access it from them.

Microsoft Azure: This cloud is used and offered by Microsoft. It offers IaaS, PaaS and SaaS for its enterprise software and developer tools. If you have ever used Office 365 products, then you have used SaaS.

Google Cloud: The Google cloud platform is a universal cloud for Google’s vast ecosystem and also for other products such as Microsoft Office it allows collaboration, storage of data and also other services offered by its cloud computing suite.

IBM SmartCloud: Using Private, Public and Hybrid deployment models IBM SmartCloud provides a full range of IaaS, Paas and SaaS cloud computing services to businesses. Using the pay-as-you-go model, this cloud generates revenue for IBM.