Information Technology Reference
In-Depth Information
vApps,” but for now, sufi ce it to say that the vCenter Server virtual appliance (which you may
see referred to as VCVA or VCSA) offers an option to quickly and easily deploy a full installation
of vCenter Server on SuSE Linux.
Because of the breadth of features included in vCenter Server, most of these core services are
discussed in later chapters. For example, Chapter 9, “Creating and Managing Virtual Machines,”
discusses VM deployment, VM management, and template management. Chapter 11,
“Managing Resource Allocation,” and Chapter 12, “Balancing Resource Utilization,” deal with
resource management for ESXi hosts and VMs, and Chapter 13, “Monitoring VMware vSphere
Performance,” discusses alarms. In this chapter, we'll focus primarily on ESXi host manage-
ment, but we'll also discuss scheduled tasks, statistics and logging, and event management.
There are other key items about vCenter Server that you can't really consider core services.
Instead, these underlying features support the core services provided by vCenter Server. In
order to help you more fully understand the value of vCenter Server in a vSphere deployment,
we need to provide a closer look at the following:
Centralized user authentication
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Web-based client server
Inventory system
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Extensible framework
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Centralizing User Authentication Using vCenter Single Sign-On
Centralized user authentication is not listed as a core service of vCenter Server, but it is essential
to how vCenter Server operates and to reducing the management overhead that vCenter Server
brings to a vSphere implementation. In Chapter 2, “Planning and Installing VMware ESXi,” we
discussed a user's authentication to an ESXi host under the context of a user account created
and stored locally on that host. Generally speaking, without vCenter Server you would need a
separate user account on each ESXi host for each administrator who needed access to the server.
As the number of ESXi hosts and required administrators grows, the number of accounts to
manage grows exponentially. There are workarounds for this overhead; one such workaround is
integrating your ESXi hosts into Active Directory, a topic we'll discuss in more detail in Chapter
8, “Securing VMware vSphere.” In this chapter, we'll assume the use of local accounts, but be
aware that using Active Directory integration with your ESXi hosts does change the picture
somewhat. In general, though, the centralized user authentication vCenter Server offers is easier
to manage than other available methods.
In a virtualized infrastructure with only one or two ESXi hosts, administrative effort is not a
major concern. Administering one or two servers would not incur incredible effort on the part
of the administrator, and creating user accounts for administrators would not be too much of a
burden.
In situations like this, vCenter Server might not be missed from a management perspective,
but it will certainly be missed from a feature set viewpoint. In addition to its management capa-
bilities, vCenter Server can perform vMotion, coni gure vSphere Distributed Resource Scheduler
(DRS), establish vSphere High Availability (HA), and use vSphere Fault Tolerance (FT). These
features are not accessible using ESXi hosts without vCenter Server. Without vCenter Server, you
also lose key functionality such as vSphere Distributed Switches, host proi les, policy-driven
storage, and vSphere Update Manager. vCenter Server is a requirement for any enterprise-level
virtualization project.
