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Server and I/O Virtualization Vs Cloud Computing Kongkon J Dutta {kongkon.job}@gmail.com Ness Technology (India) Ltd. #33,17th H Main Koramangala, Bangalore, India Introduction There is a new buzz word in the corporate community called “Cloud Computing”. Every company now wants to be in the Cloud 9 by leveraging the advantages of Cloud Computing. But a very few people knows what is Cloud Computing and how it is different from Virtualization. For an average non-geek person cloud computing is still a cloudy concept. Virtualization means to virtualize you resources. What does this mean? We shall discuss these issues in details in light of I/O and Server virtualization techniques avail today in the market. This simply means that instead of having physical resources you ought to have virtual resources. In computing terms, resources means you CPU, you memory and I/O infrastructure, be it USB or TCP/IP based Network Connectivity or Serial Com Port connections to name a few. The Myth Cloud computing and Virtualization is not the same. They address different aspects of provisioning Cloud services. When we talk about Virtualization we mean the hardware aspects of it and the means to virtualize the hardware resources. Whereas Cloud Computing is more about the software aspects of it and how to provide software solutions by utilizing the Cloud. Here most of the research is going on Automation and Web Service areas. Hardware Virtualization What is hardware virtualization? It’s basically about how we see our hardware resources. By virtualization means virtualiza the physical resources you have in you system. For instance, we can virtualize a single CPU machine into a machine which comprises of a couple of virtual CPU thereby increasing the resource utilization. Similarly the physical available memory in the system can also be virtualize. What I mean by virtualizing the memory is this. To virtualize the we need to have some software which controls the hardware rather than the Computer Operating System taking complete control of the hardware resources. And this piece of software has to sit in between you Operating System and Hardware. In modern computer science terminology they are called as hypervisor. If you go back in the history (since we can not go forward in to the future) IBM had come up with the first industry standard hypervisor way back in 1960s. They have CP/CMS operating system which has an extra layer of software which sits in between the hardware and the operating system. In modern time, our time we have hypervisor from the pioneer VMWare, and they are the guys who shown the new world the power of virtualization and virtual resources. VMWare popularize the concept of virtual hardware and operating system. VMWare has an software called VMWare Server using which we can create a virtual machine. This is the first time I am using the term virtual machine. So, what is a virtual machine? A virtual machine is a software object which simulates as a real computer system by sitting inside a real operating system in a real hardware. For example, lets consider a simplistic scenario. You can have a Linux Fedora Guest VM in VMWare Player inside a Windows XP Host machine. Does this Host and Guest words sounds confusing to you? The Host machine is the one which has the real access to the hardware or the base operating system and Guest is the one that runs inside VMWare Player as a virtual machine. The virtual machine does not have real access to the computer hardwares in the system. It it the Host system that assigns parts of the available hardware resources to the virtual machine. VMware, the commercial virtualization solution, is an example of full virtualization. Paravirtualization is provided by Xen, User-Mode Linux (UML) and others. Too many products In recent time since everyone wants to be in the same space, different companies has created different solutions addressing the similar problem if not the same problem. To name a few are VMWare has a bunce of products that can be used for virtualize the hardware infrastructure. ESX is one of the main component in this regard. ESX is a hypervisor which controls the hardware resources. And there are operating systems on top of it. Similarly we have Open Source Xen community. Xen is an open source server virtualization solution. Citrix has bought Xen sometime back in 1993. And since then the popular XenServer become Citrix XenServer. And the good thing that Citrix did is, they made Xen opensource. After Xen become open source Oracle started building up their own front end management infrastructure to work with the Xen Hyperviror. Oracle picked up the same backend Xen community source and build up a web based Java GUI to monitor and manage the Xen Server, they call it as Oracle VM Manager. In case of Citrix the management part is done by a desktop GUI component in case of Windows Host machine. Using both the GUI based Xen Server Manager we can connect to multiple Xen Servers or use multiple VMs in side a single Xen Server. Then there is VirtualBox from Sun, which is again another software that provide provisioning virtual machine like VMWare Player. Microsoft has also followed the trend and come up with their own hypervisor software called HyperV to manage Windows Servers. The latest entrance in this space is the Red Hat supported and Linux Kernel community back uped KVM, the Linux Kernel Virtual Machine. Don’t get confused with the older KVM switch which means Keyboard, Video, Mouse. KVM is the Linux kernel provided virtualization infrastructure. KVM supports native virtualization using the advance virtualization hardware support on the processor. In case of Intel it is Intel VT-x and in case of AMD it is AMD-V I/O Virtualization Then come the need to virtualize your I/O infrastructure. I/O is always a bottole neck in the progress of computer industry. As the process speed has grown up over the years, so is the RAM speed and the hard disk technology. Hard disks are replaced by faster flash disks. but what about you network speed, this can not be the same. Everybody wants to download in the DVD speed. So, there is the concept of I/O virtualization and various other technologies around it. TCP/IP played a much bigger role in software communication standards than any other network protocol. Different new tecnologies emmersed and died also. A very good example of this is the dying InfiniBand Protocol and Architecture. InfiniBand provides a very high speed interconnect of 2.5Gbps per channel and there can be multiple channels. There are 1x, 2x, 4x and 8x connections available in the market moving the speed bariier to 2.5Gbps to 24Gbps. But they use a whole new hardware infrastructure to make the interconnect, also the protocol stack is different from TCP/IP. Now things are going back to zero and people are going back to good old TCP/IP for a better connectivity solution. Solutions like TOE (TCP Offload Engine) came into picture whereby the most of the checksum calculations are offloaded to a dedicated ASIC/Chip inside a adapter card. While we talk about the technical details of the complexity into the TCP/IP Network driver, as an when the network adapter collects a new network packet it has to make sure that the packet is in good health. So, to make sure of the health of the incoming packet, the already computer checksum is recalculated on the receiving side to compare with the original result. This is very time consuming task, and hence in modern days network adapters this is offloaded into the TCP Offload Engine hardware. When computations are directly done in the dedicated hardware it is always faster than doing it in the software using the CPU resources of the host machine. Along the same line of TO Engine, Chelsio Communications provide a solution called Unified Wire which transmits iSCSI, RDMA and TCP/IP traffice across the same wired line with the complexity handled by the driver software and the network adapter hardware. Broadcom has TCP Offload Engine embedded inside their mother board, there by enhancing the capabalities of the Network Card, hence enhances the performance of the overall system. When it comes to virtualize I/O infrastructure at the corporate level it involves two aspects: virtualize the network intrastructure and virtualize storage infrastucture. In this space too there are couple of companies working to achieve the same goal. One good example is Xsigo Systems Inc. They have a hardware Chassis which provides the hardware infrastucture for I/O virtualization in terms of virtualized NIC for network resources and virtualize HBA for the storage infrastructutre. So, this hadrare chassis provided vNIC and vHBA to Host Servers. Again the host servers can be physical server or a virtualize server like the XenServer. By adding virtual NICs and virtual HBAs you can attain the network speed and extra disk space from attaching to various Logical Unit Number(LUN)s exposed to the vHBA(s). In simple terms, a LUN is a logical entity that converts raw physical disk space into logical storage space, which a host server's OS can access and use. Various fancy little other features were also provided in the Xsigo Systems solution like boot the host server using vNIC from the LUN or to install OS in a LUN associated to a vHBA over the vNIC. The bandwidth can be extended with the help of features like NIC Teaming. In a similar fashion storage can be made high available(HA) using Multipathing of virtual HBAs. Enough has been taught about the Virtualization, and I guess I conveyed the concept correctly. Let’s check out Cloud Computing. In the Cloud space, Amazon is the pioneer leader to come up with concepts like Elastic Compute Cloud(EC2). Amazon already started providing services for High Performance Computing (HPC) also. EC2 is Amazon’s cloud computing platform based on the Amazon Web Service (AWS). EC2 allows users to rent virtual machine and install applications without the hassle of traditional software model. EC2 tries to address the problems of tradition computing like virus, backups and software updates etc. Resources will be rent out to individuals on need basis and on demand basis. This is the fundamental concept behind software/hardware-as-a-service. At the back end EC2 runs on Xen. Web Services plays the most important role when it comes to Cloud Computing. Provisioning virtual machine is the basic job done by the web services and then managing the virtual machine. The companies that provide cloud services run web services at the back end to facilitate the services they provide. For example Amazon Web Services is a java based application interface to be used in various applications. The web services plays the role mostly comes when to provisioning the hardware resources. References: 1. History of Hypervisor Meta Words: IBM Tivoli Provisioning Manager, VMWare Server/ESX/Workstation/Player, Sun VirtualBox, IBM LPAR/DLPAR, Windows HyperV, HyperVisor, Citrix/Oracle Xen, Linux KVM, Intel Ring, Paravirtualization, HPC, enterprise cloud, private cloud.
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IBM Tivoli Provisioning Manager, VMWare Server/ESX/Workstation/Player, Sun VirtualBox, IBM LPAR/DLPAR, Windows HyperV, HyperVisor, Citrix/Oracle Xen, ,
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