Mastering VMware vSphere 6.7 is the fully updated edition of the bestselling guide to VMware's virtualization solution. With comprehensive coverage of this industry-leading toolset, this book acts as an informative guide and valuable reference. Step-by-step instruction walks you through installation, configuration, operation, securit...
What exactly is virtualization? As this concise book explains, virtualization is a smorgasbord of technologies that offer organizations many advantages, whether you're managing extremely large stores of rapidly changing data, scaling out an application, or harnessing huge amounts of computational power. With this guide, you get an ov...
Mastering KVM Virtualization Download Pdf
Get a novel perspective on Linux containers and understand the world of virtualization. This book takes you down the rabbit hole to discover what lies below the API. You'll go on a journey of virtualization and see how containers are realized in the Linux world. Linux Containers and Virtualization details the data structures within t...
vSphere Storage is one of the three main infrastructure components of a vSphere deployment (Compute, Storage, and Network).Mastering VMware vSphere Storage begins with an insightful introduction to virtualization and creating your own virtual machines. We then talk about VMware vCenter Server and virtual machine management, as well as man...
Citrix XenServer is a powerful, open source virtualization platform for the development and management of cloud, server, and desktop infrastructures. It is based on the Xen hypervisor, which powers the Amazon EC2 public Cloud. Citrix XenServer 6.2 provides unparalleled flexibility and scalability compared to other virtualization platforms...
As x86 server virtualization becomes mainstream for even the most demanding applications, the criticality of managing the heath and efficiency of virtualized environments is more important than ever. vRealize Operations Manager 6.0 (vROps 6.0) is the key to simplify operations of your virtualized environment and move from being reactive t...
This chapter provides the reader with an insight into the prevailing technologies in Linux virtualization and their advantage over others. There are a total of 14 chapters in this book, which are lined up to cover all the important aspects of KVM virtualization, starting from KVM internals and advanced topics such as software defined networking, performance tuning, and optimization, to physical to virtual migration.
In philosophy, virtual means "something that is not real". In computer science, virtual means "a hardware environment that is not real". Here, we duplicate the functions of physical hardware and present them to an operating system. The technology that is used to create this environment can be called virtualization technology, in short, virtualization. The physical system that runs the virtualization software (hypervisor or Virtual Machine Monitor) is called a host and the virtual machines installed on top of the hypervisor are called guests.
Virtualization first appeared in Linux in the form of User-mode Linux (UML) and it started the revolution required to bring Linux into the virtualization race. Today, there is a wide array of virtualization options available in Linux to convert a single computer into multiple ones. Popular Linux virtualization solutions include KVM, Xen, QEMU, and VirtualBox. In this book, we will be focusing on KVM virtualization.
Openness, flexibility, and performance are some of the major factors that attract users to Linux virtualization. Just like any other open source software, virtualization software in Linux is developed in a collaborative manner; this indirectly brings users the advantages of the open source model. For example, compared to closed source, open source receives wider input from the community and indirectly helps reduce research and development costs, improves efficiency, and performance and productivity. The open source model always encourages innovation. The following are some of the other features that open source provides:
However, in the context of our book, we will discuss virtualization mainly in terms of software (hypervisor-based) virtualization. From this angle, virtualization is the process of hiding the underlying physical hardware so that it can be shared and used by multiple operating systems. This is also known as platform virtualization. In short, this action introduces a layer called a hypervisor/VMM between the underlying hardware and the operating systems running on top of it. The operating system running on top of the hypervisor is called the guest or virtual machine.
Server consolidation: It is well understood that virtualization helps in saving power and having a smaller energy footprint. Server consolidation with virtualization will also reduce the overall footprint of the entire data center. Virtualization reduces the number of physical or bare metal servers, reducing networking stack components and other physical components, such as racks. Ultimately, this leads to reduced floor space, power savings, and so on. This can save you more money and also help with energy utilization. Does it also ensure increased hardware utilization? Yes, it does. We can provision virtual machines with the exact amount of CPU, memory, and storage resources that they need and this will in turn make sure that hardware utilization is increased.
Service isolation: Suppose no virtualization exists; in this scenario, what's the solution to achieve service isolation? Isn't it that we need to run one application per physical server? Yes, this can make sure that we achieve service isolation; however, will it not cause physical server sprawl, underutilized servers, and increased costs? Without any doubt, I can say that it does. The server virtualization helps application isolation and also removes application compatibility issues by consolidating many of these virtual machines across fewer physical servers. In short, service isolation technique this brings the advantage of simplified administration of services.
Faster server provisioning: Provisioning a bare metal system will consume some time, even if we have some automated process in the path. But in case of virtualization, you can spawn a virtual machine from prebuilt images (templates) or from snapshots. It's that quick, as you can imagine. Also, you really don't have to worry about physical resource configuration, such as "network stack", which comes as a burden for physical or bare metal server provisioning.
Disaster recovery: Disaster recovery becomes really easy when you have a virtualized data center. Virtualization allows you to take up-to-date snapshots of virtual machines. These snapshots can be quickly redeployed so you can reach to a state where everything was working fine. Also, virtualization offers features such as online and offline VM migration techniques so that you can always move those virtual machines elsewhere in your data center. This flexibility assists with a better disaster recovery plan that's easier to enact and has a higher success rate.
Dynamic load balancing: Well, this depends on the policies you set. As server workloads vary, virtualization provides the ability for virtual machines, which are overutilizing the resources of a server, to be moved (live migration) to underutilized servers, based on the policies you set. Most of the virtualization solutions come with such policies for the user. This dynamic load balancing creates efficient utilization of server resources.
Faster development and test environment: Think of this, if you want to test environment in a temporary manner. It's really difficult to deploy it in physical servers, isn't it? Also, it won't be of much worth if you set up this environment in a temporary manner. But it's really easy to set up a development or test environment with virtualization. Using a guest operating system/VM enables rapid deployment by isolating the application in a known and controlled environment. It also eliminates lots of unknown factors, such as mixed libraries, caused by numerous installs. Especially, if it's a development or test environment, we can expect severe crashes due to the experiments happening with the setup. It then requires hours of reinstallation, if we are on physical or bare metal servers. However, in case of VMs, it's all about simply copying a virtual image and trying again.
Improved system reliability and security: A virtualization solution adds a layer of abstraction between the virtual machine and the underlying physical hardware. It's common for data on your physical hard disk to get corrupted due to some reason and affect the entire server. However, if it is stored in a virtual machine hard disk, the physical hard disk in the host system will be intact, and there's no need to worry about replacing the virtual hard disk. In any other instance, virtualization can prevent system crashes due to memory corruption caused by software such as the device drivers. The admin has the privilege to configure virtual machines in an independent and isolated environment. This sandbox deployment of virtual machines can give more security to the infrastructure because the admin has the flexibility to choose the configuration that is best suited for this setup. If the admin decides that a particular VM doesn't need access to the Internet or to other production networks, the virtual machine can be easily configured behind the network hop with a completely isolated network configuration and restrict the access to the rest of the world. This helps reduce risks caused by the infection of a single system that then affects numerous production computers or virtual machines.
OS independence or a reduced hardware vendor lock-in: Virtualization is all about creating an abstraction layer between the underlying hardware and presenting a virtual hardware to the guest operating systems running on top of the stack. Virtualization eliminates the hardware vendor lock-in, doesn't it? That being said, with virtualization the setup has to be tied down to one particular vendor/platform/server, especially when the virtual machines don't really care about the hardware they run on. Thus, data center admins have a lot more flexibility when it comes to the server equipment they can choose from. In short, the advantage of virtualization technology is its hardware independence and encapsulation. These features enhance availability and business continuity. One of the nice things about virtualization is the abstraction between software and hardware. 2ff7e9595c
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