Xen Virtualization Essentials eBook. $ Though the concept of virtualization is far from new, recent requirements such as the need to maximize hardware. About Xen Virtualization Essentials. ronaldweinland.info download and download the full PDF and ePub versions of this Xen eBook for only. ronaldweinland.info ▫ . Essentials integrates with Hyper-V and XenServer will be supported by.
|Language:||English, Spanish, Japanese|
|ePub File Size:||17.68 MB|
|PDF File Size:||16.79 MB|
|Distribution:||Free* [*Register to download]|
Configuring and Installing a Xen Hardware Virtual Machine (HVM) Guest Checking Hardware Support for Xen Hardware Virtual Machines (HVM). Thank you for choosing Virtualization Essentials. This book is part My heartfelt thanks also go to the virtual team at Sybex: Pete Gaughan, David . Citrix Xen. This book is about one such virtualization solution known as Xen. Xen is a feature rich, open source, hypervisor-based virtualization solution which, in spite of its.
In the chapter entitled Installing and Configuring RHEL 5 Xen Virtualization , the difference between full-virtualization and para-virtualization was explained together with a tutorial on how to create and run a para-virtualized virtual machine containing another Linux distribution as a guest operating system. The goal of this chapter is to provide a tutorial that takes the reader through the steps involved in using Xen to run Windows as a guest operation system on an RHEL 5 system using full-virtualization. This chapter assumes that a Xen-enabled kernel and associated tools are installed and that the Xen kernel is the currently running kernel. Hardware Requirements for Xen-based Full Virtualization on RHEL Although this topic was covered in the preceding chapter, the importance of having the correct hardware support is such that it warrants a second mention. In the latter instance, reboot your system and enter the system BIOS settings to verify that it is enabled. If you have the required Windows installation media available, insert it into the physical disk drive of your RHEL 5 system.
This will launch the New Virtual Machine wizard which will appear with a welcome screen. Click the Forward button to proceed to the Virtual Machine Name screen. In the text box provided, enter an appropriate name for the new virtual machine. For the purposes of this tutorial we will use the name WindowsVM. Click Forward to proceed.
Configuring Xen Virtualization Method The next screen displayed by the new virtual machine will provide the option to choose the method of virtualization. Since we plan to install an unmodified guest in the form of Windows we will need to select the Full Virtualization method.
If this option is disabled the most likely cause is that either the system CPU does not include the required virtualization features, or that they are currently disabled in the BIOS. Assuming the option is not disabled, select Full Virtualization and ensure that Xen is selected from the Hypervisor menu: Once the new VM is configured to use Xen full virtualization, click Forward to proceed.
You'll begin by learning what virtualization is and how it works within the computing environment, then you'll dive right into building your own virtual machine. You'll learn how to set up the CPU, memory, storage, networking, and more as you master the skills that put you in-demand on the job market. Each chapter focuses on a specific goal, and concludes with review questions that test your understanding as well as suggested exercises that help you reinforce what you've learned.
As more and more companies are leveraging virtualization, it's imperative that IT professionals have the skills and knowledge to interface with virtualization-centric infrastructures. This book takes a learning-by-doing approach to give you hands-on training and a core understanding of virtualization. Understand how virtualization works Create a virtual machine by scratch and migration Configure and manage basic components and supporting devices Develop the necessary skill set to work in today's virtual world Virtualization was initially used to build test labs, but its use has expanded to become best practice for a tremendous variety of IT solutions including high availability, business continuity, dynamic IT, and more.
Cloud computing and DevOps rely on virtualization technologies, and the exponential spread of these and similar applications make virtualization proficiency a major value-add for any IT professional.
Vendors in exchange promise to give you these services without any interrupt that make the availability in high level. In the next sections, we can see the significance of all words we discuss in this section and trying to interpret them.
As stated before, all the machines we are using here is virtual, it means they are pieces of software that easily we can copy them whenever and anywhere we want.
So if any trouble happens to our physical servers or related devices, we can easily move the virtual machines to a new location. It means the virtual machines easily can move across our data center to avoid downtime of the service which that particular virtual machine will provide.
Actually, in this case even we do not need to do that, as we know the new servers which used for virtualized data centers, do not have any physical storage that directly attached to the servers and they just do the processing part of all jobs. So if one server failed, we can use the other servers to do processing jobs. With the help of this great ability of virtualization technology down time of those servers which provides important services even in the case of, maintaining of the hardware which is a very important issue in data centers, become a zero time.
The dynamic attribute of the virtualization is helping the cloud providers that offer such an environment that any request can respond on-demand. In cloud computation process, if any of virtual machines need to increase one of the resources, it can be increased by the cloud management system. Even if a user needed to increase any of the resources, as service level agreement, the cloud management system can manage these resources and user environment can be expanded.
This expansion and shrinking the available resources for active virtual machines is ability of dynamic virtualization technology. But now a days, most of the people who are talking about cloud computing, just talks about the scalability of cloud without mentioning anything about virtualization. This way of reviewing the abilities without reviewing the background of it, make it more difficult to understand and discuss. Instead of physical connection between two physical computers, we can virtually connect two of virtual computers together.
By help if virtualization even cables converted to the virtual cables and it reduced the time which the data center technicians spend on the cabling and maintaining the cables. It is like communication in LAN networks. Each computer has one specific, unique IP and they are communicating with each other. Network virtualization also continues the term of scalability in a cloud environment.
The important point also here is a dynamic scalability of network resources . If two VMs want to communicate to each other through a network, there are two scenarios. The first scenario is communication between two VM on a same physical host.
In this case all devices will be virtualized devices like virtual switches or virtual firewalls.
As shown in the figure, the base communication will be through a hypervisor. In the second scenario, two VMs are on different physical host which communication is a combination of physical communication and virtual communication. After that the communication will be between physical NICs and at the last step, the packets will send to another virtual NIC . Figure 6: VMs communication on two physical hosts.
But, still there are some difficulties in this environment.
One the challenges in the virtualized environment is about the IPs. The problem will arise within the VM migration process . The migration of VMs is the operation that may happen in different situation like the process of energy efficiency of cloud environment. In this situation the VM needs to migrate from one physical host to another. In this case, the VM needs to release old resources such as network resources and reallocate in the new host. This releasing old IP and reassign new IP from the other network pool may make a problem for us.
In some management software designers only considered only IPv6 or vice versa, but most of the heterogeneous data centers are must support both IP versions . Thus, like all other types of networks, virtual network also and its management should consider such difficulties. The physical storages are not directly connected to the servers; they are connected to the servers through the network.
One of the most popular protocols use for storage virtualization is a storage area network SAN and network attached storage NAS. They use TCP for reliable communication. This new technology helps availability of data even if several servers go down . The significant point of the storage virtualization is to hide geographical positions of the data over the cloud environment. For this significant point of the storage virtualization maps the logical storage to the physical storage as blocks of data .
In storage virtualization still the management of the data which can be distributed among the network is the one of the important issues in cloud storage .
Vendors promise to the scalability and on-demand of their cloud make the most important challenges for cloud providers. Performance and transfer rate became important issues not only for the cloud providers, but it will affect the user experience.
To overcome this kind of problems, the bandwidth needs to be increased otherwise it can be a bottleneck for data transfer ; and it becomes a serious problem for the providers which affect the cost of services if they do not face the bandwidth limitation.
Another key issue for the cloud storage is the data security. The management system should controls how own the data and should have access to the data. Transferring data over the network without proper protection may cause the security risk of user data . The guest operating systems that loaded into different virtual machines, using virtual addresses and these addresses will mapped into the physical memory addresses.
But guest operating systems can not directly access to the actual physical memory and responsible for controlling of this operation is a hypervisor. We can say the hypervisor is the heart of the virtualization which maps virtual devices to the physical ones. VMs are using the virtual memories based on the paging techniques. In reality, there are three different types of memory we can enumerate here.
One is used by the guest OS, we can call it as virtual memory. Another memory is addressed in the hypervisor and we can call it as real memory and the last one is the physical memory . The guest OS map virtual memory to the real memory which controls by the hypervisor. After that, real memory or hypervisor memory maps to the physical memory.
It means if an application needs to retrieve the data, before access the exact data, the virtual address should be translated into a physical address and then the VM can use that page of memory. So, the retrieving data take two times more than traditional hardware based systems in the same conditions.