Virtualization is becoming a central component of data center strategies and as a result, it is an increasingly important aspect of the information technology strategy of many organizations. Organizations across many different sectors and of varying sizes are working to deploy more sophisticated computing infrastructures that use virtualization in order to maximize resource utilization. Virtualization provides organizations with a number of advantages, including better efficiency, better resource utilization, an improved ability to scale solutions and services while often achieving cost savings, and significant return on investment.
However, supporting a highly virtualized computing infrastructure can be challenging for many organizations. Managing and deploying many virtual machines can be a challenge, and managing the many different configurations can be overwhelming, especially for heterogeneous computing environments comprised of different kinds of servers with different processors, cores, memory, and so on. For enterprises making use of virtualized environments to serve core enterprise applications and house critical data, ensuring availability and reliability in a virtualized environment can be daunting.
As the leading virtualization company, VMware too has recognized the challenges in managing complex, enterprise datacenters and computing environments. To address these challenges and associated complexities, it introduced vCenter and vSphere to help administrators manage complex virtualized environments. Like many commercial software products, vCenter and vSphere are really a suite of software components that come in a number of different versions. While they make life easier for the administrator, they too are complex software products.
As in many situations, learning to use a complex software suite often requires assistance and sometimes, it is best done through examples. This book plays an important role in helping to fill an administrator's understanding and use of vCenter and vSphere. This book assumes that the reader/user will have access to vCenter that is deployed and has hosts and datastores. This book notes that this could be a trial license, which should be sufficient to allow the reader to explore vCenter and vSphere. For those in the process of acquiring vCenter, this is a useful suggestion as it will help determine versions of vSphere that may be needed.
The key focus is on vCenter and vSphere and the key functions and capabilities of the suite of software. This book covers a number of different requirements of virtualized environments—not all environments will have all the requirements. Thus, the text can be used by administrators across a range of environments; readers can "pick-and-choose" the chapters that are most relevant to their needs.
The core focus of the text covers the means of dealing with key enterprise needs: Availability, Scalability, Efficiency, and Optimization (chapters 2 to 5). The other chapters are useful as well. Chapter 1, covers basic vCenter tasks and examines different vSphere editions (I found this chapter particularly useful). Chapters 6 and 7 cover basic administrative tasks and ways to improve the manageability of the virtual environment.
This book is very well written and there is consistent organization throughout the chapters. There are numerous step-by-step instructions on how to do certain tasks and many of these are accompanied by screenshots. This gives the book a "cookbook" flavor as there are many recipes (in fact, the text refers to many of the steps as "recipes") for tasks, and coupling this with the actual use of the software provides an excellent learning model.
This book falls into three logical sections: Chapter 1, basics of vCenter and vSphere; chapters 2-5, central enterprise tasks; Chapters 6 and 7, basic tasks and manageability.
This chapter provides a discussion and comparison of various vSphere editions, what software components and kits are included under the different licenses, what each license covers (for example, CPUs), and so on. There is a very nice walk-through of the different editions, licenses, and options, and it can be very helpful in making a choice that is most appropriate for your organization. This chapter covers a number of basic vCenter tasks, such as booting a VM from a virtual CD, using hosts with different CPUs in one cluster, running vCenter on a VM, accessing hosts via SSH, and so on. There are, of course, screenshots to help the reader. I found this chapter to be particularly useful, since it clearly explained the different vSphere editions.
This chapter covers vCenter's approach in dealing with availability. It covers how to configure and tune the High Availability (HA) and Fault Tolerance (FT) options. Different scenarios are reviewed, including prioritizing VMs for recovery, admission control, backup, and replication. There are useful discussions on resource consumption for HA and FT, particularly on network traffic, memory, and disk. There are also some useful "tips" or best practices since HA and FT can impact available resources. Another useful element of this chapter is that it explains some of the messages that the administrator may get while configuring HA and FT, and it explains why these messages are being generated.
For many organizations, one main advantage of virtualized data centers is the ability to scale. This chapter covers some of the options and features available in vCenter to improve the administrator's efficiency. This includes templates, customizations, host profiles, and other solutions designed to automate and simplify VM, host deployment, and configuration. Templates enable an administrator to take a set of tasks used for the deployment of virtual servers and package them. With this template, the administrator can deploy as many servers as needed and perform only tasks that are different from each other. In situations where there is a requirement to deploy many VMs in a short period of time, the process can be automated using scripts; the use of PowerCLI scripts is covered as an alternative way to deploy or upgrade hosts.
This chapter describes some features and enhancements offered by vCenter along with vSphere 5, designed to increase environment efficiency. This includes new virtual hardware, SCSI controllers and network cards, efficient space utilization, power consumption, and the utilization of flash memory to make hosts and VMs faster. Of particular interest is the portion of this chapter that covers features of vSphere that enable a reduction in power consumption during off-peak hours, including Distributed Power Management (DPM), which allows certain hosts to be placed in the standby mode. This chapter also provides a discussion on how to leverage nonuniform memory access (NUMA) in modern server memory design.
This chapter looks at resource usage and the options available in vSphere to optimize resource consumption. The common strategies in this area include better distribution of load between hosts and datastores, prioritization of resource consumers according to their importance and needs, as well as limiting resource usage, including CPU, memory, network, and storage I/O. Ensuring that there are enough resources, limiting resources, and balancing loads between hosts are the responsibilities of the Distributed Resource Scheduler (DRS). The Storage Distributed Resource Scheduler (SDRS) has been introduced in vSphere 5 to deal with storage performance. The common tasks utilizing both of these is covered.
Tasks covered in this chapter, as the title suggests, are basic administrative tasks that will help administrators increase control and visibility of their environment. These tasks include setting up rules for virtual machine placement, setting alarms and e-mail alerts, automating basic tasks with a scheduler (for example, powering on/off, cloning), and controlling the space and location of snapshots. It also discusses automating VM placement with an affinity, which is related to optimization issues discussed in Chapter 5.
A variety of useful administrative tasks, which can make an administrator's life easier, are covered in this chapter. These tasks can improve the overall manageability of the environment. This chapter covers Tagging, a new feature introduced in vSphere 5, which can help categorize objects in the environment. There is also a section that covers a new command-line interface, esxcli, which has been introduced in vSphere 5; it offers improved syntax and additional functionality, including network and security policies, firewall, and VIN management.
This is an excellent text for those just getting into vCenter as well as more experienced administrators moving into more complex environments. With recipes for tasks coupled with screenshots, it is a very useful "desk side" companion.
Michael Bauer
Professor
Department of Computer Science
The University of Western Ontario