A grant table is an interface which grants access to memory pages to Virtual Machines that do not own the pages. [1] Grant tables are implemented on Xen hypervisor.
Grant tables are generally used in inter-virtual machine communication, when one of the communicating VM's requires pages owned by the other VM.
In computing, a virtual machine (VM) is the virtualization or emulation of a computer system. Virtual machines are based on computer architectures and provide the functionality of a physical computer. Their implementations may involve specialized hardware, software, or a combination of the two. Virtual machines differ and are organized by their function, shown here:
Xen is a free and open-source type-1 hypervisor, providing services that allow multiple computer operating systems to execute on the same computer hardware concurrently. It was originally developed by the University of Cambridge Computer Laboratory and is now being developed by the Linux Foundation with support from Intel, Citrix, Arm Ltd, Huawei, AWS, Alibaba Cloud, AMD, Bitdefender and EPAM Systems.
x86 virtualization is the use of hardware-assisted virtualization capabilities on an x86/x86-64 CPU.
A hypervisor, also known as a virtual machine monitor (VMM) or virtualizer, is a type of computer software, firmware or hardware that creates and runs virtual machines. A computer on which a hypervisor runs one or more virtual machines is called a host machine, and each virtual machine is called a guest machine. The hypervisor presents the guest operating systems with a virtual operating platform and manages the execution of the guest operating systems. Unlike an emulator, the guest executes most instructions on the native hardware. Multiple instances of a variety of operating systems may share the virtualized hardware resources: for example, Linux, Windows, and macOS instances can all run on a single physical x86 machine. This contrasts with operating-system–level virtualization, where all instances must share a single kernel, though the guest operating systems can differ in user space, such as different Linux distributions with the same kernel.
Platform virtualization software, specifically emulators and hypervisors, are software packages that emulate the whole physical computer machine, often providing multiple virtual machines on one physical platform. The table below compares basic information about platform virtualization hypervisors.
virt-manager is a desktop virtual machine monitor primarily developed by Red Hat.
VMware ESXi is an enterprise-class, type-1 hypervisor developed by VMware, a subsidiary of Broadcom, for deploying and serving virtual computers. As a type-1 hypervisor, ESXi is not a software application that is installed on an operating system (OS); instead, it includes and integrates vital OS components, such as a kernel.
Hardware virtualization is the virtualization of computers as complete hardware platforms, certain logical abstractions of their componentry, or only the functionality required to run various operating systems. Virtualization emulates the hardware environment of its host architecture, allowing multiple OSes to run unmodified and in isolation. At its origins, the software that controlled virtualization was called a "control program", but the terms "hypervisor" or "virtual machine monitor" became preferred over time.
Infrastructure as a service (IaaS) is a cloud computing service model where a cloud services vendor provides computing resources such as storage, network, servers, and virtualization. This service frees users from maintaining their own data center, but they must install and maintain the operating system and application software. Iaas provides users high-level APIs to control details of underlying network infrastructure such as backup, data partitioning, scaling, security and physical computing resources. Services can be scaled on-demand by the user. According to the Internet Engineering Task Force (IETF), such infrastructure is the most basic cloud-service model. IaaS can be hosted in a public cloud, a private cloud, or a hybrid cloud.
Open Virtualization Format (OVF) is an open standard for packaging and distributing virtual appliances or, more generally, software to be run in virtual machines.
Sun xVM was a product line from Sun Microsystems that addressed virtualization technology on x86 platforms. One component was discontinued before the Oracle acquisition of Sun; the remaining two continue under Oracle branding.
In computing, virtualization (v12n) is a series of technologies that allows dividing of physical computing resources into a series of virtual machines, operating systems, processes or containers.
Oracle VM Server for x86 is a server virtualization offering from Oracle Corporation. Oracle VM Server for x86 incorporates the free and open-source Xen hypervisor technology, supports Windows, Linux, and Solaris guests and includes an integrated Web based management console. Oracle VM Server for x86 features fully tested and certified Oracle Applications stack in an enterprise virtualization environment.
Live migration, also called migration, refers to the process of moving a running virtual machine (VM) or application between different physical machines without disconnecting the client or application. Memory, storage, and network connectivity of the virtual machine are transferred from the original guest machine to the destination. The time between stopping the VM or application on the source and resuming it on destination is called 'downtime'. When the downtime of a VM during live migration is small enough that it is not noticeable by the end user, it is called a 'seamless' live migration.
libvirt is an open-source API, daemon and management tool for managing platform virtualization. It can be used to manage KVM, Xen, VMware ESXi, QEMU and other virtualization technologies. These APIs are widely used in the orchestration layer of hypervisors in the development of a cloud-based solution.
Temporal isolation or performance isolation among virtual machine (VMs) refers to the capability of isolating the temporal behavior of multiple VMs among each other, despite them running on the same physical host and sharing a set of physical resources such as processors, memory, and disks.
XenClient is a discontinued desktop virtualization product developed by Citrix. It runs virtual desktops on endpoint devices. The product reached end of-life in December 2016. XenClient runs both operating system and applications locally in the end users device, without the need for a connection to a data center, which is why it is used in environments with limited connectivity, disconnected operation on laptops, and other scenarios where local execution is desired while keeping management centralized.
Second Level Address Translation (SLAT), also known as nested paging, is a hardware-assisted virtualization technology which makes it possible to avoid the overhead associated with software-managed shadow page tables.
In computer security, virtual machine (VM) escape is the process of a program breaking out of the virtual machine on which it is running and interacting with the host operating system. In theory, a virtual machine is a "completely isolated guest operating system installation within a normal host operating system", but this isn't always the case in practice.
OrionVM Wholesale Pty Limited is an Australian infrastructure as a service provider and white-label cloud platform. Resellers present customers with a rebranded interface for deploying virtual machine instances, which are only billed for what their customers use. Cloud Harmony benchmarked the OrionVM Cloud Platform's InfiniBand-backed network storage as the world's fastest in 2011.