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  OpenVZ KVM Cloud Disk Resizekvm and cloud can only increase in size Yes No No Rebootless UpgradesChanges to kernel, disk, or memory do not require reboots Yes No No Lowest OverheadThe shared kernel on openvz has lower overhead Yes No No Support ALL OSOpenVZ only supports linux operating systems No Yes Yes True VM IsolationOnly KVM and Cloud based virtualization provides a true VM isolation No Yes Yes Disk CacheDisk cache supported Yes Yes Yes Swap SpaceSwap space is supported No Yes Yes OpenVZ OpenVz is is a linux based virtualization platform based on the Linux Kernel. OpenVZ allows a physical server to run multiple isolated operating system instances known as containers. OpenVz can only run linux based operating systems such as Centos, Fedora, Gentoo, and Debian. One disadvantage of OpenVZ users are not able to make any kernel modifications. All virtual servers have to get along with the kernel version the host runs on. However because it doesn’t have the overhead of a true hypervisor it is very fast and efficient over Kvm, Xen, KVM, VMware and Cloud.   KVM, Xen, VMware The next three platforms can be grouped into the same category because they work almost identically. The differences that they do have will not be noticeable on the virtual server and the end user. All three platforms provide true virtualization resources are not shared between the host kernel or other virtual servers. Almost any operating system can run on three platforms. We choose to use the KVM platform because it supported by the Centos operating system that we use as the host OS.   Cloud Cloud is the new term companies large and small are kicking around. There is no true definition on what a cloud is or how it is supposed to be designed. And in our opinion the term “cloud” that applies to VPS hosting is no different then a VPS that has failover, redundancy or backup. So coining a the new term “cloud” and the extra hype is completely not necessary. A typical cloud setup runs on the KVM, XEN, or VMware platform. The difference is on the type of hardware that is used. instead of having storage located on the host server all data is stored on much larger SAN/NAS array with multiple disks. Raid is used to prevent disk failure in the physical array. And in the best case scenario a second array is added incase the entire array fails. The host server accesses the storage via Ethernet. in the event of a host server failure spare host servers are on standby to startup when needed. Downtime during the failure would be a reboot of your operating system. At YIsolutions our cloud setup runs on the KVM platform with two storage arrays. The advantage of cloud is a truly redundant environment. All aspects of hardware failure are 100% covered. if you are looking for a 0 downtime solution this is truly it. Cloud hosting costs much more than standard vps server because of all the additional hardware required.

Overview It’s easy to confuse virtualization and cloud, particularly because they both revolve around creating useful environments from abstract resources. However, virtualization is a technology that allows you to create multiple simulated environments or dedicated resources from a single, physical hardware system, and clouds are IT environments that abstract, pool, and share scalable resources across a network. To put it simply, virtualization is a technology, where cloud is an environment. Clouds are usually created to enable cloud computing, which is the act of running workloads within that system.  Cloud infrastructure can include a variety of bare-metal, virtualization, or container software that can be used to abstract, pool, and share scalable resources across a network to create a cloud. At the base of cloud computing is a stable operating system (like Linux®). This is the layer that gives users independence across public, private, and hybrid environments. If you have intranet access, internet access, or both already established, virtualization can then be used to create clouds, though it’s not the only option.  With virtualization, software called a hypervisor sits on top of physical hardware and abstracts the machine’s resources, which are then made available to virtual environments called virtual machines. These resources can be raw processing power, storage, or cloud-based applications containing all the runtime code and resources required to deploy it. If the process stops here, it’s not cloud—it’s just virtualization.  Virtual resources need to be allocated into centralized pools before they’re called clouds. Adding a layer of management software gives administrative control over the infrastructure, platforms, applications, and data that will be used in the cloud. An automation layer is added to replace or reduce human interaction with repeatable instructions and processes, which provides the self-service component of the cloud. You’ve created a cloud if you’ve set up an IT system that: Can be accessed by other computers through a network. Contains a repository of IT resources. Can be provisioned and scaled quickly. Clouds deliver the added benefits of self-service access, automated infrastructure scaling, and dynamic resource pools, which most clearly distinguish it from traditional virtualization. Virtualization has its own benefits, such as server consolidation and improved hardware utilization, which reduces the need for power, space, and cooling in a datacenter. Virtual machines are also isolated environments, so they are a good option for testing new applications or setting up a production environment. A practical comparison Virtualization can make 1 resource act like many, while cloud computing lets different departments (through private cloud) or companies (through a public cloud) access a single pool of automatically provisioned resources. Virtualization Virtualization is technology that allows you to create multiple simulated environments or dedicated resources from a single, physical hardware system. Software called a hypervisor connects directly to that hardware and allows you to split 1 system into separate, distinct, and secure environments known as virtual machines (VMs). These VMs rely on the hypervisor’s ability to separate the machine’s resources from the hardware and distribute them appropriately. Cloud Computing Cloud computing is a set of principles and approaches to deliver compute, network, and storage infrastructure resources, services, platforms, and applications to users on-demand across any network. These infrastructure resources, services, and applications are sourced from clouds, which are pools of virtual resources orchestrated by management and automation software so they can be accessed by users on-demand through self-service portals supported by automatic scaling and dynamic resource allocation.   Virtualization Cloud Definition Technology Methodology Purpose Create multiple simulated environments from 1 physical hardware system Pool and automate virtual resources for on-demand use Use Deliver packaged resources to specific users for a specific purpose Deliver variable resources to groups of users for a variety of purposes Configuration Image-based Template-based Lifespan Years (long-term) Hours to months (short-term) Cost High capital expenditures (CAPEX), low operating expenses (OPEX) Private cloud: High CAPEX, low OPEXPublic cloud: Low CAPEX, high OPEX Scalability Scale up Scale out Workload Stateful Stateless Tenancy Single tenant Multiple tenants How do I move from virtualization to cloud computing? If you already have a virtual infrastructure, you can create a cloud by pooling virtual resources together, orchestrating them using management and automation software, and creating a self-service portal for users—or you can let something like Red Hat® OpenStack® Platform do a lot of that work for you. But moving from virtualization to cloud computing isn’t that simple when you’re bound to a vendor’s enterprise-license agreement, which might limit your ability to invest in modern technologies like clouds, containers, and automation systems.  

Overview It’s easy to confuse virtualization and cloud, particularly because they both revolve around creating useful environments from abstract resources. However, virtualization is a technology that allows you to create multiple simulated environments or dedicated resources from a single, physical hardware system, and clouds are IT environments that abstract, pool, and share scalable resources across a network. To put it simply, virtualization is a technology, where cloud is an environment. Clouds are usually created to enable cloud computing, which is the act of running workloads within that system.  Cloud infrastructure can include a variety of bare-metal, virtualization, or container software that can be used to abstract, pool, and share scalable resources across a network to create a cloud. At the base of cloud computing is a stable operating system (like Linux®). This is the layer that gives users independence across public, private, and hybrid environments. If you have intranet access, internet access, or both already established, virtualization can then be used to create clouds, though it’s not the only option.  With virtualization, software called a hypervisor sits on top of physical hardware and abstracts the machine’s resources, which are then made available to virtual environments called virtual machines. These resources can be raw processing power, storage, or cloud-based applications containing all the runtime code and resources required to deploy it. If the process stops here, it’s not cloud—it’s just virtualization.  Virtual resources need to be allocated into centralized pools before they’re called clouds. Adding a layer of management software gives administrative control over the infrastructure, platforms, applications, and data that will be used in the cloud. An automation layer is added to replace or reduce human interaction with repeatable instructions and processes, which provides the self-service component of the cloud. You’ve created a cloud if you’ve set up an IT system that: Can be accessed by other computers through a network. Contains a repository of IT resources. Can be provisioned and scaled quickly. Clouds deliver the added benefits of self-service access, automated infrastructure scaling, and dynamic resource pools, which most clearly distinguish it from traditional virtualization. Virtualization has its own benefits, such as server consolidation and improved hardware utilization, which reduces the need for power, space, and cooling in a datacenter. Virtual machines are also isolated environments, so they are a good option for testing new applications or setting up a production environment. A practical comparison Virtualization can make 1 resource act like many, while cloud computing lets different departments (through private cloud) or companies (through a public cloud) access a single pool of automatically provisioned resources. Virtualization Virtualization is technology that allows you to create multiple simulated environments or dedicated resources from a single, physical hardware system. Software called a hypervisor connects directly to that hardware and allows you to split 1 system into separate, distinct, and secure environments known as virtual machines (VMs). These VMs rely on the hypervisor’s ability to separate the machine’s resources from the hardware and distribute them appropriately. Virtualization Cloud computing is a set of principles and approaches to deliver compute, network, and storage infrastructure resources, services, platforms, and applications to users on-demand across any network. These infrastructure resources, services, and applications are sourced from clouds, which are pools of virtual resources orchestrated by management and automation software so they can be accessed by users on-demand through self-service portals supported by automatic scaling and dynamic resource allocation.   Virtualization Cloud Definition Technology Methodology Purpose Create multiple simulated environments from 1 physical hardware system Pool and automate virtual resources for on-demand use Use Deliver packaged resources to specific users for a specific purpose Deliver variable resources to groups of users for a variety of purposes Configuration Image-based Template-based Lifespan Years (long-term) Hours to months (short-term) Cost High capital expenditures (CAPEX), low operating expenses (OPEX) Private cloud: High CAPEX, low OPEXPublic cloud: Low CAPEX, high OPEX Scalability Scale up Scale out Workload Stateful Stateless Tenancy Single tenant Multiple tenants How do I move from virtualization to cloud computing? If you already have a virtual infrastructure, you can create a cloud by pooling virtual resources together, orchestrating them using management and automation software, and creating a self-service portal for users—or you can let something like Red Hat® OpenStack® Platform do a lot of that work for you. But moving from virtualization to cloud computing isn’t that simple when you’re bound to a vendor’s enterprise-license agreement, which might limit your ability to invest in modern technologies like clouds, containers, and automation systems.  

Overview Kernel-based Virtual Machine (KVM) is an open source virtualization technology built into Linux®. Specifically, KVM lets you turn Linux into a hypervisor that allows a host machine to run multiple, isolated virtual environments called guests or virtual machines (VMs). KVM is part of Linux. If you’ve got Linux 2.6.20 or newer, you’ve got KVM. KVM was first announced in 2006 and merged into the mainline Linux kernel version a year later. Because KVM is part of existing Linux code, it immediately benefits from every new Linux feature, fix, and advancement without additional engineering. How does KVM work? KVM converts Linux into a type-1 (bare-metal) hypervisor. All hypervisors need some operating system-level components—such as a memory manager, process scheduler, input/output (I/O) stack, device drivers, security manager, a network stack, and more—to run VMs. KVM has all these components because it’s part of the Linux kernel. Every VM is implemented as a regular Linux process, scheduled by the standard Linux scheduler, with dedicated virtual hardware like a network card, graphics adapter, CPU(s), memory, and disks. Implementing KVM Long story short, you have to run a version of Linux that was released after 2007 and it needs to be installed on X86 hardware that supports virtualization capabilities. If both of those boxes are checked, then all you have to do is load 2 existing modules (a host kernel module and a processor-specific module), an emulator, and any drivers that will help you run additional systems. But implementing KVM on a supported Linux distribution—like Red Hat Enterprise Linux—expands KVM’s capabilities, letting you swap resources among guests, share common libraries, optimize system performance, and a lot more. Building a virtual infrastructure on a platform you’re contractually tied to may limit your access to the source code. That means your IT developments are probably going to be more workarounds than innovations, and the next contract could keep you from investing in clouds, containers, and automation. Migrating to a KVM-based virtualization platform means being able to inspect, modify, and enhance the source code behind your hypervisor. And there’s no enterprise-license agreement because there’s no source code to protect. It’s yours. KVM features KVM is part of Linux. Linux is part of KVM. Everything Linux has, KVM has too. But there are specific features that make KVM an enterprise’s preferred hypervisor. Security KVM uses a combination of security-enhanced Linux (SELinux) and secure virtualization (sVirt) for enhanced VM security and isolation. SELinux establishes security boundaries around VMs. sVirt extends SELinux’s capabilities, allowing Mandatory Access Control (MAC) security to be applied to guest VMs and preventing manual labeling errors. Storage KVM is able to use any storage supported by Linux, including some local disks and network-attached storage (NAS). Multipath I/O may be used to improve storage and provide redundancy. KVM also supports shared file systems so VM images may be shared by multiple hosts. Disk images support thin provisioning, allocating storage on demand rather than all up front. Hardware support KVM can use a wide variety of certified Linux-supported hardware platforms. Because hardware vendors regularly contribute to kernel development, the latest hardware features are often rapidly adopted in the Linux kernel. Memory management KVM inherits the memory management features of Linux, including non-uniform memory access and kernel same-page merging. The memory of a VM can be swapped, backed by large volumes for better performance, and shared or backed by a disk file. Live migration KVM supports live migration, which is the ability to move a running VM between physical hosts with no service interruption. The VM remains powered on, network connections remain active, and applications continue to run while the VM is relocated. KVM also saves a VM’s current state so it can be stored and resumed later. Performance and scalability KVM inherits the performance of Linux, scaling to match demand load if the number of guest machines and requests increases. KVM allows the most demanding application workloads to be virtualized and is the basis for many enterprise virtualization setups, such as datacenters and private clouds. Scheduling and resource control In the KVM model, a VM is a Linux process, scheduled and managed by the kernel. The Linux scheduler allows fine-grained control of the resources allocated to a Linux process and guarantees a quality of service for a particular process. In KVM, this includes the completely fair scheduler, control groups, network name spaces, and real-time extensions. Lower latency and higher prioritization The Linux kernel features real-time extensions that allow VM-based apps to run at lower latency with better prioritization (compared to bare metal). The kernel also divides processes that require long computing times into smaller components, which are then scheduled and processed accordingly. Managing KVM It’s possible to manually manage a handful of VM fired up on a single workstation without a management tool. Large enterprises use virtualization management software that interfaces with virtual environments and the underlying physical hardware to simplify resource administration, enhance data analyses, and streamline operations. Red Hat created Red Hat Virtualization for exactly this purpose. KVM and Red Hat We believe in KVM so much that it’s the sole hypervisor for all of our virtualization products, and we’re continually improving the kernel code with contributions to the KVM community. But since KVM is part of Linux, it’s already included in Red Hat Enterprise Linux—so why would you want Red Hat Virtualization? Well, Red Hat has 2 versions of KVM. The KVM that ships with Red Hat Enterprise Linux has all of the hypervisor functionality with basic management capabilities, allowing customers to run unlimited isolated virtual machines on a single host. Red Hat Virtualization contains an advanced version of KVM that enables enterprise management of unlimited guest machines. It’s ideal for use in datacenter virtualization, technical workstations, private clouds, and in development or production.