Server Virtualization

Server virtualization is the masking of server resources, including the number and identity of individual physical servers, processors, and operating systems, from server users. The server administrator uses a software application to divide one physical server into multiple isolated virtual environments. The virtual environments are sometimes called virtual private servers, but they are also known as guests, instances, containers or emulations.
There are three popular approaches to server virtualization: the virtual machine model, the paravirtual machine model, and virtualization at the operating system (OS) layer.
Virtual machines are based on the host/guest paradigm. Each guest runs on a virtual imitation of the hardware layer. This approach allows the guest operating system to run without modifications. It also allows the administrator to create guests that use different operating systems. The guest has no knowledge of the host's operating system because it is not aware that it's not running on real hardware. It does, however, require real computing resources from the host -- so it uses a hypervisor to coordinate instructions to the CPU.
The hypervisor is called a virtual machine monitor (VMM). It validates all the guest-issued CPU instructions and manages any executed code that requires addition privileges. VMware and Microsoft Virtual Server both use the virtual machine model.
The paravirtual machine (PVM) model is also based on the host/guest paradigm -- and it uses a virtual machine monitor too. In the paravirtual machine model, however, The VMM actually modifies the guest operating system's code. This modification is called porting. Porting supports the VMM so it can utilize privileged systems calls sparingly. Like virtual machines, paravirtual machines are capable of running multiple operating systems. Xen and UML both use the paravirtual machine model.
Virtualization at the OS level works a little differently. It isn't based on the host/guest paradigm. In the OS level model, the host runs a single OS kernel as its core and exports operating system functionality to each of the guests. Guests must use the same operating system as the host, although different distributions of the same system are allowed. This distributed architecture eliminates system calls between layers, which reduces CPU usage overhead. It also requires that each partition remain strictly isolated from its neighbors so that a failure or security breach in one partition isn't able to affect any of the other partitions. In this model, common binaries and libraries on the same physical machine can be shared, allowing an OS level virtual server to host thousands of guests at the same time. Virtuozzo and Solaris Zones both use OS-level virtualization.
Server virtualization can be viewed as part of an overall virtualization trend in enterprise IT that includes storage virtualization, network virtualization, and workload management. This trend is one component in the development of autonomic computing, in which the server environment will be able to manage itself based on perceived activity. Server virtualization can be used to eliminate server sprawl, to make more efficient use of server resources, to improve server availability, to assist in disaster recovery, testing and development, and to centralize server administration.

Installing VMware vCenter Server

How To Configure a SQL Server ODBC Connection to a Remote Database
How to create an ODBC connection and connect vCenter Server to a preconfigured SQL Server 2005 database.

1. From your vCenter Server system desktop, select Start > Programs > Administrative Tools > Data Sources (ODBC).
2. Click System DSN tab and click Add.
3. Select the SQL Native Client driver.
4. Click Finish.
5. When prompted by the Create a New Data Source to SQL Server Wizard, enter the values below:
a. Fill in the Name field.
b. Fill in the Description. You can type in vCenter Server Database.
c. Fill in the Server field by entering the host name of the SQL Server. If you see more than one SQL server in the list, make sure that you enter the correct SQL server name.
d. The UNC user account you logged in with appears in the Login ID field.
e. For the field Connect to SQL Server to obtain default settings for the additional configuration options, leave the check box selected.
f. Change the default database to your assigned database (and not the master database).
6. Click Test Data Source. If the test does not complete successfully, back up in the ODBC wizard and verify the information you entered.
7. Click OK to return to ODBC Microsoft SQL Server Setup dialog box.
8. Click OK to return to the ODBC Data Source Administrator dialog box. Verify that your new data source appears in the list of system DSNs.
9. Click OK to close the ODBC Data Source Administrator dialog box.


How To Install vCenter Server
1. Go to location of the vCenter Server installation software.
2. Start VMware vCenter Installer:
- If you have an ISO image or physical CD-ROM mounted on the vCenter Server system’s CD-ROM drive and autorun is enabled, the installer main window appears.
- For files that are unzipped from a Zip archive or that are on a network share, open the directory containing the files and double-click autorun.exe file.
3. Click vCenter Server link.
4. When prompted by installation wizard, do the following:
a. Select the setup language and click OK.
b. Click Next (Welcome Page).
c. Click Next (End-User Patent Agreement).
d. Select I agree to the terms in the license agreement and click Next (License Agreement).
e. Type in your User Name.
f. Type in your Organization. Click Next.
g. Type in the License key and click Next.
h. If you are not connecting to a remote database, select Install a Microsoft SQL Server 2005 Express instance and click Next.
If you are connecting to a remote database, select Use an existing supported database, select your DSN and click Next.
-In the second Database Options dialog box , type in your Database Username. Enter your Database password.
-If a warning appears about reinitializing the database, select Replace my existing database with an empty one. If you are installing vCenter Server for the first time, you will not see this warning.
i. Select Use SYSTEM Account and click Next (vCenter Server Service).
j. Accept the default Destination Folder and click Next.
k. Accept the default vCenter Server Linked Mode Options and click Next.
l. Accept the defaults Configure Ports and click Next.
m. Accept the default vCenter Server JVM Memory and click Next.
n. Click Install (Ready to Install the Program).
5. When installation is complete, click Finish to exit wizard.
6. Close VMware vCenter Installer window.


How To Install the vSphere Client on the vCenter Server System
How to install the VMware vSphere Client on your vCenter Server system and verify that installation was successful.

1. Go to location of the vCenter Server installation software.
2. Start VMware vCenter Installer.
3. In Vmware vCetner Installer window, click vSphere Client to start installation wizard.
4. When prompted by the installation wizard, do the following:
a. Select the setup language.
b. Click Next (Welcome page).
c. Click Next (End-User Patent Agreement).
d. Select I agree to the terms in the license agreement and click Next.
e. Type in your User Name.
f. Type in your Organization and click Next.
g. Select your Destination Folder and click Next.
h. Click Install (Ready to Install the Program).
5. Click Finish when the installation is complete.
6. Close VMware vCenter Installer window.
7. Log in to the vCenter Server with the vSphere Client.
a. Double-click the vSphere Client icon on your vCenter Server system.
b. In the vSphere Client login dialog box, enter your vCetner Server system IP address or host name in IP address/Name and select the use Windows session credentials check box.
c. Click Login.
d. Select Install this certificate and do not display any security warnings for “<host_name>” to prevent this warning from being displayed in the future.
e. Click Ignore to proceed with the connection.
f. Click OK when the VMware Evaluation Notice window appears, warning that your evaluation license expires within 60 days.
8. Verify that the Hosts and Clusters inventory view is displayed.
9. In the vSphere Client menu bar, select File > Exit to close the vSphere Client.
10. Log out of vCenter Server system.