There comes a time when you are working on something, and a need arises where you want to use another computing instance, but it is tough to work on many machines at the same time.
Hence, there is a necessity to create virtual machines that allow you to work on many computing instances simultaneously. The challenge is to be able to run many computing instances, and that is where hypervisors come into the picture.
Having the capability to configure the virtual environment is also an added advantage that many developers and software professionals yearn for. Here, hypervisor fills the void.
Hypervisor acts as a governing mechanism. It is a software layer that allows you to create and work on many virtual machines on a single hardware unit.
Hypervisor is primarily divided into two types based on their working: Type 1 hypervisor is one that runs on the host hardware directly. These are also called as bare-metal hypervisor.
On the other hand, type 2 hypervisor runs on a software i.e. an operating system. System administrators use both types of open source hypervisor based on their specific needs.
Businesses can choose any of the two, depending upon their infrastructure and needs for managing virtualization. So here is a list of top 10 open source hypervisor, which are used by professionals.
Xen is among the market leaders in the open-source hypervisor arena. The Xen Project, as it is known, is licensed under GPLv2.
Like its competition, the open-source hypervisor also comes in a commercial version from Citrix and Oracle VM. It has cloud support, which includes Openstack and Cloudstack, among others.
Xen supports virtualization of x86 IA64, ARM, among other architectures. Xen has been used in the virtualization of a wide array of guest OS. A few of the OS supported by Xen are Windows, Solaris, and other versions of the BSD OS.
A kernel-based virtual machine (KVM) is a project based upon HNU/Linux that has been developed for x86 computers.
It has an interesting way of functioning, it has a kernel module kvm.ko which is a loadable kernel, and this turns the Linux kernel into a hypervisor.
With this, the VMs gain direct access to the hardware. It also comes with kernels, which are processor-specific such as kvm-amd.ko and kvm-intel.ko.
Many people do believe that this is a type 2 hypervisor because of the kernel’s involvement, but the developers have claimed that it is, in fact, type 1 since it runs directly on the x86 hardware.
Microsoft is not quite known to launch open-source software, but it introduced Hyper-V as an evaluation product which is available to download free of cost.
The main aim was to launch their open-source hypervisor in competition to the others in the market. The free Hyper-V server 2012 is a standalone software and comes with all the features which Microsoft had included in its Windows Server 2012.
These include nested virtualization and cluster rolling, among others.
VMware, the name synonymous with proprietary products and definitely not free, has provided its premium hypervisor product VMware ESXi to be downloaded for free.
Though it is not particularly an open-source hypervisor, it does provide some level of customization for the users as some of its components’ source files can be downloaded.
It has a hack, though. If you want to use the full feature enabled version, you can do so for 60 days if the serial number is not entered.
Lguest is a lightweight hypervisor which is built into the Linux kernel version 2.6.23. Although it was removed in the version 4.14 but can still be installed in the successive kernels with out-of-tree patches.
It comes with para-virtualized solutions such as a virtualized I/O subsystem and does not include any fancy bells and whistles in comparison to other open-source hypervisor.
But it is a good option to develop and test the kernel boot. Its functioning is quite interesting. During initialization Lguest allocates memory and maps it to the kernel’s address space and loads a small hypervisor in this allocated memory.
This type 2 hypervisor can run on many OS such as Solaris, Linux, Mac, and Windows. It is compatible with both x86 and x64 OS, and it is quite portable. It allows virtual machines to be imported or exported using the Open Virtualization Format (OVF), which is a standout feature of this product.
Xvisor provides virtualization for ARMv5, ARMv7a, x86_64, and other architectures. Its code is highly can be ported with ease to most 32 and 64 bit architectures till the time they have PMMU and a port for the GCC compiler.
This type 2 open-source hypervisor is what every enterprise needs. It is simple to use with a very practical and easy to use UI. It is ideal for running and evaluating OS and applications on a virtual machine on Linux and Windows.
It is an enterprise approach that is an open-source container-based virtualization platform created for Linux. OpenVZ has the ability to create many virtual machines in a Linux container.
Thus, the admin is able to use each of these containers as individual servers. They can reboot independently of each other on the same physical server.
It is an open source hypervisor based on the Unix operating system. SmartOS integrates OpenSolaris technology with Linux’s Kernel-based Virtual Machine Virtualization technology.
SmartOS can be downloaded as an ISO image. Even though developed by Joyent, SmartOS can be downloaded and used by anyone for free.
System administrators can pick and choose which open-source hypervisor they wish to choose, which is based on varying factors.
Eventually, it all comes down to getting the work done, and hence whichever open-source hypervisor meets their need in the best possible fashion generally makes the cut.
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