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 (which emulates computer hardware). 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 (where users share hardware, storage, and network devices), a private cloud (users do not share resources), or a hybrid cloud (combination of both).
35-544: Iland Internet Solutions was a provider of hosted cloud infrastructure as a service for production business applications, disaster recovery and business continuity , testing and development, and software as a service enablement for independent software vendors. 11:11 Systems agreed to buy iland in December 2021. When the merger completed in January 2022, all of iland's services and assets were transferred to 11:11. At
70-456: A compound annual growth rate (CAGR) of 22.6% from 2023 to 2030. This growth is primarily driven by the adoption of cloud-based infrastructure within the Banking, Financial Services, and Insurance ( BFSI ) sector, which employs these technologies to enhance scalability and reduce operational costs. The UK Government encourages departments to use public cloud solutions as a first option. IaaS
105-483: A BSD license (and continues to maintain) PV drivers for Windows. Third-party developers have built a number of tools (known as Xen Management Consoles) to facilitate the common tasks of administering a Xen host, such as configuring, starting, monitoring and stopping of Xen guests. Examples include: The Xen hypervisor is covered by the GNU General Public Licence, so all of these versions contain
140-703: A competitive enterprise product. To support embedded systems such as smartphone/ IoT with relatively scarce hardware computing resources, the Secure Xen ARM architecture on an ARM CPU was exhibited at Xen Summit on April 17, 2007, held in IBM TJ Watson. The first public release of Secure Xen ARM source code was made at Xen Summit on June 24, 2008 by Sang-bum Suh , a Cambridge alumnus, in Samsung Electronics. On October 22, 2007, Citrix Systems completed its acquisition of XenSource, and
175-499: A later date. Xen can scale to 4095 physical CPUs, 256 VCPUs per HVM guest, 512 VCPUs per PV guest, 16 TB of RAM per host, and up to 1 TB of RAM per HVM guest or 512 GB of RAM per PV guest. The Xen hypervisor has been ported to a number of processor families: Xen can be shipped in a dedicated virtualization platform, such as XCP-ng or XenServer (formerly Citrix Hypervisor, and before that Citrix XenServer, and before that XenSource's XenEnterprise). Alternatively, Xen
210-552: A service (BaaS). Headquartered in Houston, Texas and London, UK, iland delivers cloud services from its data centers throughout the Americas, Europe, Asia and Australia. iland provided cloud-based disaster recovery and business continuity services. Other services included desktop virtualization integrated with a company's overall business continuity and disaster recovery plan , a cloud environment specifically for software as
245-490: A service (SaaS) providers and merged virtual cloud and physical colocation center servers for custom enterprise configurations. It provides a data replication service for Dell EqualLogic customers. Infrastructure as a service The US National Institute of Standards and Technology (NIST) defines infrastructure as a service as: The capability provided to the consumer is provision processing, storage, networks, as well as other fundamental computing resources where
280-460: A special hypercall ABI , instead of certain architectural features. Through paravirtualization, Xen can achieve high performance even on its host architecture (x86) which has a reputation for non-cooperation with traditional virtualization techniques. Xen can run paravirtualized guests ("PV guests" in Xen terminology) even on CPUs without any explicit support for virtualization. Paravirtualization avoids
315-564: A virtual-machine disk-image library, raw block storage , file or object storage , firewalls, load balancers, IP addresses, virtual local area networks (VLANs), and software bundles. IaaS-cloud providers supply resources on-demand from the large pools of equipment installed in data centers . For wide-area connectivity, customers can use either the Internet or carrier clouds (dedicated virtual private networks , VPNs). To deploy their applications, users install operating-system images and
350-403: Is Linux containers , which run in isolated partitions of a Linux kernel that runs directly on the physical hardware. Containers are isolated, secured and managed using Linux cgroups and namespaces. Containerisation offers higher performance than virtualization because there is no hypervisor overhead. The global IaaS market is projected to reach a value of $ 411.9 billion by 2030, expanding at
385-494: Is distributed as an optional configuration of many standard operating systems. Xen is available for and distributed with: Guest systems can run fully virtualized (which requires hardware support), paravirtualized (which requires a modified guest operating system), or fully virtualized with paravirtualized drivers (PVHVM ). Most operating systems which can run on PCs can run as a Xen HVM guest. The following systems can operate as paravirtualized Xen guests: Xen version 3.0 introduced
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#1732776605239420-471: Is in use within the UK Government but the technology community within government recommends consideration of Platform as a Service (PaaS) in cases where a department may not have IaaS skills and management capacity. Xen Xen (pronounced / ˈ z ɛ n / ) is a free and open-source type-1 hypervisor , providing services that allow multiple computer operating systems to execute on
455-430: Is known as hardware-assisted virtualization , however, in Xen this is known as hardware virtual machine (HVM). HVM extensions provide additional execution modes, with an explicit distinction between the most-privileged modes used by the hypervisor with access to the real hardware (called "root mode" in x86) and the less-privileged modes used by guest kernels and applications with "hardware" accesses under complete control of
490-662: Is mostly used for booting. Administrators can "live migrate" Xen virtual machines between physical hosts across a LAN without loss of availability. During this procedure, the LAN iteratively copies the memory of the virtual machine to the destination without stopping its execution. The process requires a stoppage of around 60–300 ms to perform final synchronization before the virtual machine begins executing at its final destination, providing an illusion of seamless migration. Similar technology can serve to suspend running virtual machines to disk, "freezing" their running state for resumption at
525-473: The QEMU project to provide I/O virtualization to the virtual machines. The system emulates hardware via a patched QEMU "device manager" (qemu-dm) daemon running as a backend in dom0. This means that the virtualized machines see an emulated version of a fairly basic PC. In a performance-critical environment, PV-on-HVM disk and network drivers are used during the normal guest operation, so that the emulated PC hardware
560-534: The Xen hypervisor . Citrix also used the Xen brand itself for some proprietary products unrelated to Xen, including XenApp and XenDesktop . On April 15, 2013, it was announced that the Xen Project was moved under the auspices of the Linux Foundation as a Collaborative Project. The Linux Foundation launched a new trademark for "Xen Project" to differentiate the project from any commercial use of
595-537: The Xen Project moved to the xen.org domain. This move had started some time previously, and made public the existence of the Xen Project Advisory Board (Xen AB), which had members from Citrix , IBM , Intel , Hewlett-Packard , Novell , Red Hat , Sun Microsystems and Oracle . The Xen Advisory Board advises the Xen Project leader and is responsible for the Xen trademark, which Citrix has freely licensed to all vendors and projects that implement
630-410: The application software on the cloud infrastructure. Users patch and maintain the operating systems. IaaS services are typically billed as a utility: cost reflects the amount of resources allocated or consumed. Typically, IaaS involves the use of a cloud orchestration technology such as OpenStack , Apache CloudStack , or OpenNebula . It manages the creation of a virtual machine (VM) and decides on
665-411: The avoidance of downtime. Virtualization also has benefits when working on development (including the development of operating systems): running the new system as a guest avoids the need to reboot the physical computer whenever a bug occurs. Sandboxed guest systems can also help in computer-security research, allowing study of the effects of some virus or worm without the possibility of compromising
700-559: The capability to run Microsoft Windows as a guest operating system unmodified if the host machine's processor supports hardware virtualization provided by Intel VT-x (formerly codenamed Vanderpool) or AMD-V (formerly codenamed Pacifica). During the development of Xen 1.x, Microsoft Research , along with the University of Cambridge Operating System group, developed a port of Windows XP to Xen — made possible by Microsoft 's Academic Licensing Program. The terms of this license do not allow
735-407: The consumer is able to deploy & run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, & deployed applications; and possibly limited control of select networking components (e.g., host firewalls). IaaS clouds often offer additional resources such as
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#1732776605239770-559: The host domain (dom0). Xen originated as a research project at the University of Cambridge led by Ian Pratt , a senior lecturer in the Computer Laboratory , and his PhD student Keir Fraser. The first public release of Xen was made in 2003, with v1.0 following in 2004. Soon after, Pratt and Fraser along with other Cambridge alumni including Simon Crosby and founding CEO Nick Gault created XenSource Inc. to turn Xen into
805-414: The host processor supports x86 virtualization , e.g., Intel VT-x and AMD-V ), or paravirtualized operating systems whereby the operating system is aware that it is running inside a virtual machine, and so makes hypercalls directly, rather than issuing privileged instructions. Xen Project boots from a bootloader such as GNU GRUB , and then usually loads a paravirtualized host operating system into
840-439: The host system. Finally, hardware appliance vendors may decide to ship their appliance running several guest systems, so as to be able to execute various pieces of software that require different operating systems. Xen offers five approaches to running the guest operating system: Xen provides a form of virtualization known as paravirtualization, in which guests run a modified operating system. The guests are modified to use
875-572: The hypervisor (i.e. physical host) in order to start it. A hypervisor runs virtual machines (VMs) as guests. Pools of hypervisors in the cloud operational system can support large numbers of virtual machines and the ability to scale services up and down according to demand by customers. Hypevisors include Xen , Oracle VirtualBox , Oracle VM , KVM , VMware ESX /ESXi, or Microsoft Hyper-V . It also enables VM migration between hosts, allocates storage volumes, and attaches them to VMs that track usage information for billing. An alternative to hypervisors
910-409: The hypervisor (in x86, known as "non-root mode"; both root and non-root mode have Rings 0–3). Both Intel and AMD have contributed modifications to Xen to exploit their respective Intel VT-x and AMD-V architecture extensions. Use of ARM v7A and v8A virtualization extensions came with Xen 4.3. HVM extensions also often offer new instructions to allow direct calls by a paravirtualized guest/driver into
945-560: The hypervisor, typically used for I/O or other operations needing high performance. These allow HVM guests with suitable minor modifications to gain many of the performance benefits of paravirtualized I/O. In current versions of Xen (up to 4.2) only fully virtualized HVM guests can make use of hardware facilities for multiple independent levels of memory protection and paging. As a result, for some workloads, HVM guests with PV drivers (also known as PV-on-HVM, or PVH) provide better performance than pure PV guests. Xen HVM has device emulation based on
980-679: The mainline kernel. The releases up to 3.0.4 also added: Internet hosting service companies use hypervisors to provide virtual private servers . Amazon EC2 (from August 2006 to November 2017), IBM SoftLayer , Liquid Web, Fujitsu Global Cloud Platform , Linode , OrionVM and Rackspace Cloud use Xen as the primary VM hypervisor for their product offerings. Virtual machine monitors (also known as hypervisors) also often operate on mainframes and large servers running IBM, HP, and other systems. Server virtualization can provide benefits such as: Xen's support for virtual machine live migration from one host to another allows load balancing and
1015-447: The most privileged domain ("dom0") - the only virtual machine which by default has direct access to hardware. From the dom0 the hypervisor can be managed and unprivileged domains ("domU") can be launched. The dom0 domain is typically a version of Linux or BSD . User domains may either be traditional operating systems, such as Microsoft Windows under which privileged instructions are provided by hardware virtualization instructions (if
1050-518: The need to emulate a full set of hardware and firmware services, which makes a PV system simpler to manage and reduces the attack surface exposed to potentially malicious guests. On 32-bit x86, the Xen host kernel code runs in Ring 0 , while the hosted domains run in Ring 1 (kernel) and Ring 3 (applications). CPUs that support virtualization make it possible to run unmodified guests, including proprietary operating systems (such as Microsoft Windows). This
1085-451: The older "Xen" trademark. A new community website was launched at xenproject.org as part of the transfer. Project members at the time of the announcement included: Amazon, AMD, Bromium, CA Technologies, Calxeda, Cisco, Citrix, Google, Intel, Oracle, Samsung, and Verizon. The Xen project itself is self-governing. Since version 3.0 of the Linux kernel , Xen support for dom0 and domU exists in
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1120-578: The publication of this port, although documentation of the experience appears in the original Xen SOSP paper. James Harper and the Xen open-source community have started developing free software paravirtualization drivers for Windows. These provide front-end drivers for the Xen block and network devices and allow much higher disk and network performance for Windows systems running in HVM mode. Without these drivers all disk and network traffic has to be processed through QEMU-DM. Subsequently, Citrix has released under
1155-542: The requirements of the GNU General Public License (GPL), version 2. Xen Project is currently available for the IA-32 , x86-64 and ARM instruction sets . Xen Project runs in a more privileged CPU state than any other software on the machine, except for firmware . Responsibilities of the hypervisor include memory management and CPU scheduling of all virtual machines ("domains"), and for launching
1190-409: 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 . The Xen Project community develops and maintains Xen Project as free and open-source software , subject to
1225-721: The time, iland was a Premier-level partner in the VMware Service Provider Program (VSPP). Founded in 1995, iland offered its services from high availability hubs specifically designed for cloud infrastructure in Boston , Washington D.C. , Houston , Los Angeles , Dallas , Manchester, London, Amsterdam, Singapore, Melbourne, and Sydney. iland is a Premier-level partner in the VMware Service Provider Program (VSPP). iland also provided traditional colocation and global hybrid cloud services, hosting infrastructure (IaaS), disaster recovery (DRaaS), and backup as
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