 Hello everyone, myself is Supriya Ambarkar from Walton Institute of Technology, Solaapur. Today we are going to discuss a topic on virtual machines and hypervisor. The learning outcome of this session at the end students will be able to learn the basic concepts of virtual machines also students will be able to learn the importance of hypervisor. Now, first part we will see the introduction of virtual machine. A virtual machine it is a virtual representation or emulation of a physical computer means virtual machine it is a software computer like that a physical computer runs an operating system and applications. So it is comprised of a set of specification configuration files and is back backend by a particular physical resources of a host. So virtual machines are often referred to as a guest while the physical machine they run on it is referred as a host. So this is all about virtual machines. Now we will see the different benefits advantages of the virtual machines. First is a better resource utilization. There are the multiple virtual machines run on a single physical computer. So customer don't have to buy a new server every time. So they just only want to run another OS and they can get a more return from each piece of hardware they already own. So this is about the we can use the better utilization then scalability. It's easy to deploy multiple copies of a same virtual machine to better serve increases in a load. Of course, easily we are able to suppose to scale portability VMs can even move between on premises and the cloud environment. So making them useful for hybrid cloud scenarios in which you share computing resources between your data centers and cloud service providers. So easily it is a portable the next one is a flexibility creating a virtual machine is faster and easier than installing and operating system on a physical server because you can clone a virtual machine with the operating system already installed so it isn't flexible. Then in terms of security VMs improve security in several ways when compared to the operating systems running directly on a hardware. So virtual machine is a file that can be scanned for malicious software by an external programs. So here isn't we can provide the security. Now we will see the term virtualization virtualization it is a creation of virtual or abstract version of something. So here something means any hardware or system like a virtual machine virtual memory network execution environments and so on. So virtualization makes it possible to create multiple VMs each with their own operating system and application on a single physical machine a virtual machine cannot interact directly with a physical computer. So this needs a software layer which is called as a hypervisor which coordinates between it and underlying physical hardware the hypervisor allocates physical computing resources like memory processors and storage to each virtual machine. So it keeps each virtual machine separate from others so they don't interfere with each other. Now we will see the concept of hypervisor. In this diagram you are able to see the hypervisor layer after the hardware layer. So it is in middle so after that virtual machine and virtual machine 2 are there. So hypervisor allows the physical computer to separate its operating system and applications from its hardware. So then it can be divided itself into several independent virtual machines. So hypervisor is a hardware virtualization technique that allows multiple guest operating system to run on a single host system at the same time. So hypervisor having its own unique importance. So again hypervisor sometimes we can known as a virtual machine monitor that is a VMM. It manages the different VMS virtual machines as they run alongside each other. It separates virtual machines from each other logically then it assigning each its own slice of underlying computing power, memory and storages. So this prevents the virtual machines from interfering with each other. So hypervisor is useful for virtualization. Then we having a different types of hypervisors like a type 1 and type 2. Type 1 hypervisor is basically known as a bare matter approach hypervisor which run directly on a system hardware. Then similar way the type 2 hypervisor which is known as a hosted approach hypervisor it runs on a host operating system. Now we will see in details of the type 1 hypervisor. In this diagram you can see the hypervisor layer after the hardware layer. So the type 1 hypervisor is also known as bare metal approach. So it run directly on a physical hardware. Usually we can say it is a server taking the place of the OS. So you can use separate software product to create and manipulate the virtual machines on the hypervisor. So you will be required few management tools such as VMware's vSphere which let you select a guest operating system to install in the virtual machines. Few examples of the type 1 hypervisors are Hyper-V, Zen, VMware, ESX and so on. So this is all about type 1 hypervisor. Now we will see the type 2 hypervisor. Here you can see the difference between type 1 and type 2. Then hypervisor is after the host operating system layer. Type 2 hypervisor which is also known as a hosted approach hypervisor which runs as an application within a host OS. Then usually target a single user desktop with the help of type 2 hypervisor. We can manually create a virtual machine and install a gate operating system in it. We can use the hypervisor to allocate physical resources to our virtual machine. So examples of this type 2 hypervisors are virtual PC and virtual servers, again VMware, workstations, etc. Now we will see what are the different types of virtual machines are available like Windows, Android, Mac, Java, Python, Linux, VMware. Two of them we will see the Windows virtual machine. The most of the hypervisor supports virtual machines running the Windows operating system as a guest. Then the Android virtual machine in terms of this, the Google's open source Android operating system is common on mobile devices, connected home devices such as home entertainment devices and so on. So here the virtual machine concept is there. And in terms of Mac, you can use type 2 hypervisor on a Mac hardware to create virtual machines with a Mac operating system as a guest, Java virtual machine, the JVM. It translates application-level software programs to run on a particular hardware. In terms of the Python, like a JVM, Python VM doesn't run on a hypervisor, it doesn't contain a guest OS, but it is a tool that enables programs written in a Python programming language to run on a variety of a CPUs. So Python VM is there, Linux is a common guest operating system used in many virtual machines. It is also a common host operating system used to run VMs and even has its own hypervisor called the JVM that is in kernel-based virtual machines. So which is one of the, you can say the open source hypervisor. So there are so many open source hypervisors are available. Then VMWare virtual machine, VMWare was an early virtualization software vendor and it is now a popular provider of both type 1 and type 2 hypervisor. So VM software to enterprise the particular customers. So we will see the different pricing models of VMs. The most common are the pay as you go, transient or spot instances, reserved instances, dedicated hosts. Pay as you go, here the user simply pay for what they use, typically billed by the hours or seconds depends on the provider and instance type. Then transient or the spot instances, here the low, this is a lowest cost model of virtual machine. It is typically useful for applications that does not need to be always on or that are prohibitively expensive in any other models. Reserved unlike a pay as you go model, reserved instances come with an explicit term commitment and usually of between 1 or 2 years. Dedicated host, here a user typically takes on a cost of total physical server is billed and whatever increments the provider offers, dedicated servers typically hourly or monthly use. Now pause the video and write down your answer, list some open source hypervisors. The answer is the open source hypervisors are available in free of the configuration. So the list are in terms of the KVM, then ZEN, then kernel virtual machine and ZEN is there. Now we will see how to choose a VM provider. We want to think over the particular VM provider in terms of whether it gives us a reliable support, whether it is managed with a different options, whether they have given us a software integration, whether they have given the high quality network and infrastructure, then location construction, then the backup and recovery is there, scalability is, where is the CPU configuration, security layers, seamless migration support and etc. So in this way we are able to suppose to choose the VM provider. Here are the few use cases of VMs. So depends on the following options, the cloud computing is one. Virtual machines have been the fundamental unit of compute in cloud, enabling dozens of different types of applications and workloads to run and scale successfully. So cloud computing is one of the use case, then test a new operating system. A virtual machine lets you test drive a new OS on your desktop without affecting your primary OS. Then third is investigate malware, VMs are useful for malware researchers that frequently need fresh machines on which to test malicious programs so they can use. Last, the browse securely, using a virtual machine for browsing enables you to visit sites without worrying about infections. You can take snapshots of your machines and then roll back it after each browsing sessions and so on. So these are the few use cases of virtual machines. These are the references. Thank you one and all.