3. Evaluating the Infrastructure
The Microsoft deployment tools are not mutually
exclusive. You can combine them in a variety of ways, depending on the nature of your
deployment project. In many cases, the infrastructure in which you are working can
dictate how you use MDT 2010 and the other tools.
You have already seen how the MDT deployment scenarios you use depend on whether
you are deploying to new or existing workstations. Other elements of your existing
infrastructure can affect how you deploy workstations in other ways.
3.1. Using Windows Deployment Services
Windows Deployment Services provides the most convenient means of deploying MDT
2010 boot images to reference computers and target computers over the network.
Without WDS, you must create boot media to start your workstations, in the form of
CD-ROMs or DVD-ROMs or USB flash drives. In a large deployment project, this can
be extremely inconvenient. However, to use WDS, there are several infrastructure
requirements, as follows:
Windows Server
WDS is a role included in Windows Server 2008 R2 and Windows Server
2008. You must therefore have a server on your network running one of
these operating systems, on which you have installed the Windows
Deployment Services role.
PXE compliance
The workstations to which you will
deploy boot images using WDS must have network interface adapters that
are compliant with the PXE standard. There is no need for WDS discover
images in an MDT 2010 deployment because if you are going to create boot
disks, you can just use the boot images that MDT creates.
Network connectivity
To deploy large image files over the network, workstations must have a
persistent, high-speed connection to the server running WDS. Wireless
connections are not sufficient for this purpose, nor are connections that
span relatively slow wide area network (WAN) links.
Note:
DEPLOYMENTS AND NETWORK SPEED
For a large-scale Windows 7 deployment, the workstations and the computers
hosting the deployment shares, including the build computer and the server
running WDS, should all be connected to a wired network running at a minimum
speed of 100 megabits per second (Mb/sec). The computers can be on different
subnets, as long as the subnets are not connected by a slow link. If you have
wireless computers to deploy, such as laptops assigned to traveling users, your
choices are either to use a removable boot device or to connect the computer to
the wired network for the duration of the deployment process. For computers at
remote locations, you can temporarily move the workstations to the location of
the server, or move the server to the workstations.
3.2. Using Lite-Touch vs. Zero-Touch Deployments
MDT 2010 supports two different types of
deployments: Lite-Touch Installation (LTI) and the Zero-Touch Installation (ZTI),
and most of the product documentation is based on the administrator having chosen
one of these two options.
Selecting the LTI or ZTI deployment type is usually not a difficult decision.
From an infrastructure perspective, the primary difference between the two is that
a ZTI deployment requires Microsoft System Center Configuration Manager (SCCM)
2007 and an LTI deployment does not. In most cases, if you already have SCCM 2007
installed on your network, a ZTI deployment is preferable; if you do not have
SCCM, you are better off using an LTI deployment.
Other differences between the two deployment types are as follows:
User interaction
The primary advantage of a ZTI deployment is that it requires no
interaction at the workstation while the operating system installation is
occurring. This streamlines the deployment process and reduces the
incidence of configuration errors. LTI deployments, at the very least,
require someone to initiate the installation at the workstation site and
can require additional interaction as the installation proceeds. This
means that the on-site technicians require more training and
administrative credentials, and human interaction introduces a potential
source of configuration errors.
Flexibility
Most of the alternative deployment strategies discussed throughout
this article are limited to LTI deployments. ZTI is a more structured
deployment method, with fewer options.
Complexity
ZTI deployments typically require more time and effort to configure
than LTI deployments, mainly because a ZTI performs more tasks on the
workstations being deployed.
Connectivity
ZTI supports only network-based deployments; you cannot use removable
media. Therefore, all of the workstations you deploy using ZTI must have
a persistent, high-speed connection to the MDT build computer and all of
the servers involved, including the SCCM, SQL, and WDS servers. In an LTI
deployment, the workstations do not even have to be networked, although
it is preferable that they are.
Security
Because no interaction is required at the workstation during a ZTI
deployment, it is not necessary to provide users or site technicians with
administrative credentials, as it is with LTI. However, to use ZTI, you
must configure the network security and firewall policies to allow
automatic software installation and permit Remote Procedure Call (RPC)
traffic between the workstations and the deployment servers. By contrast,
you can perform an LTI deployment to workstations that prohibit automatic
software installation and are secured behind a firewall.
Upgrades
Unlike LTI, ZTI does not support the upgrade computer deployment
scenario.
Note:
IMPLEMENTING SYSTEM CENTER CONFIGURATION MANAGER
2007
SCCM 2007 is a comprehensive network
management application that can provide a wide array of administrative
services, including software distribution. As a general rule, however, it is
not worthwhile to implement SCCM on a network solely to perform workstation
deployments. There are several reasons why this is so, including the
following:
Prerequisites
SCCM 2007 requires a Microsoft SQL Server database to function, and
you cannot use the free SQL Server Express Edition for this purpose.
This adds considerably to the complexity of the installation and the
cost of implementing the product.
Installation
Installing SCCM is not simply a matter of inserting a DVD into a
drive and running a setup program. There are many optional components
and a significant amount of prior planning is required.
Client agents
SCCM requires an agent program on each computer that it manages,
which adds to the complexity of the installation as well as the
cost.
Price
Unlike MDT 2010 and the other deployment products, SCCM 2007 is not
free. You must purchase the product itself and the SQL Server product
it requires to function. In addition, you must purchase a license for
each client computer you intend to manage. As a result, the cost of
implementing SCCM on a large enterprise network can be
considerable.
If you are considering an SCCM implementation on your network, it should be
for reasons in addition to performing ZTI workstation deployments.
4. Scaling the Client Deployment Process
One of the most critical factors in selecting a Windows 7 deployment method is how
many workstations you have to deploy and the conditions under which you will be
deploying them.
In an ideal situation, you are deploying new computers on a new network with an
unlimited amount of time to complete the project. In the real world, however,
administrators rarely have all of these advantages. In fact, they often have none of
them. Therefore, you must consider the questions in the following sections and how
they affect the selection of a deployment method.
4.1. How Many Workstations?
Obviously, the number of workstations you have to deploy is one of the basic
issues in the selection of a deployment method. As discussed earlier in this
lesson, small-scale deployments can sometimes proceed without any special
methodology at all, but after you get to the point at which you decide that some
automation is required, the size of the deployment process can still make a
difference.
The
number of workstations you have to deploy can affect the overall project in two
fundamental ways. If you have several different workstation configurations to
deploy, you must consider modifications to your image creation process. However, if
the issue is how many workstations of each configuration you have to deploy, the
issues are different.
When you have 500 workstations of a specific configuration to deploy, as
opposed to 50, the process of installing the reference computer and capturing an
image need not change, but the process of deploying the image to the target
computers might. Depending on the deployment method you choose, this part of the
process can require more network bandwidth, to transfer the image files to the
workstations; more personnel, to set up the workstations and possibly initiate the
installation on each one; and time, to complete the entire deployment
process.
The more workstations you have to install, the more compelling the argument for
additional automation becomes. For example, at some point in an enterprise
environment, the manpower required to perform an LTI deployment on a large number
of workstations offsets the cost of implementing SCCM 2007 and performing a ZTI
deployment instead. It might not be worth the effort and the expense to install
SCCM for 50 workstations, but for 500, it might be a viable option, particularly
when you consider the ongoing benefits of a network management system. However, if
you will be shipping those 500 workstations to branch offices at remote locations,
where centralized network management is not practical or desirable, then LTI might
still be the better choice.
4.2. How Much Bandwidth?
If you are deploying your Windows 7 workstations over the network, you must
consider the amount of bandwidth it will take to transmit image files to each
computer. Image files can be several gigabytes in size, and deploying dozens or
hundreds of computers at once can easily flood a network, slowing the entire
process down to a crawl. This can be particularly problematic if you are deploying
workstations on a network that other people are using for their everyday work at
the same time. When performing a deployment on a working network, you must
consider not only the amount of bandwidth the infrastructure is capable of
delivering, but also the amount of bandwidth available above the requirements of
the working users.
There are several ways you can address competing claims on bandwidth during a
workstation deployment, including the following:
Stagger deployments
If you must deploy your target computers while other users are
working, you can consider installing a few at a time, to avoid flooding
the network with deployment traffic. This increases the amount of time
needed to complete the project, but in an LTI deployment, it has the
added benefit of reducing the manpower needed to perform the
installations.
Schedule deployments for off
hours
For a network that is not in production around the clock, performing
deployments at night or at other times when the network is not in use
minimizes their effect on bandwidth utilization. However, this can
increase manpower costs significantly because of overtime rates.
Use a dedicated deployment
network
Temporarily
connecting the target computers to a separate network used only for
deployment eliminates the impact on the production network. This solution
is particularly viable if you are using the new computer or replace
computer scenario because you can set up, deploy, and test the
workstations on an IT network prior to delivering them to the end users.
For the upgrade computer and refresh computer scenarios, however, this
can be impractical if it requires large numbers of computers to be moved
long distances.
Use multicasting
Deploying image files by using WDS multicasts can minimize the amount
of bandwidth consumed, as long as the entire infrastructure supports
multicast transmissions, including any routers located between the target
computers and the deployment servers.
