Configuring and Managing Windows Server-Based Hosts
Updated: September 11, 2009
Applies To: Virtual Machine Manager 2008, Virtual Machine Manager 2008 R2, Virtual Machine Manager 2008 R2 SP1
A virtual machine host is a physical computer that hosts one or more virtual machines in System Center Virtual Machine Manager 2008 (VMM) and VMM 2008 R2. You must add at least one host to your VMM environment, and a single VMM server can manage hundreds of hosts.
This topic explains how to configure and manage Windows-based, non-clustered hosts in System Center Virtual Machine Manager 2008 (VMM) and VMM 2008 R2.
|This topic applies to only Windows-based, non-clustered hosts. For information about how to configure and manage Windows-based host clusters, see Configuring Host Clusters in VMM to Support Highly Available Virtual Machines. For information about managing ESX Server hosts in VMM, see Managing a VMware Infrastructure in VMM.|
Host Types in VMM
VMM supports the following types of hosts:
Windows Server–based hosts that are located in an Active Directory Domain Services (AD DS) domain that has two-way trust with the VMM server’s AD domain.
Windows Server–based hosts that are located in an AD domain that does not have a two-way trust with the VMM server’s AD domain.
Windows Server–based hosts that are located on a perimeter network.
Windows Server–based hosts that are in a disjointed namespace, where the host’s fully qualified domain name (FQDN) resolved from the domain name service (DNS) is not the same as name obtained from AD.
VMware ESX Server hosts located anywhere in your environment.
Note Before you can add ESX Server hosts, you must add a VMware VirtualCenter server to VMM. When you add a VMware VirtualCenter server to VMM, all existing ESX Server hosts managed by that VirtualCenter server are imported to VMM. For more information about adding a VMware VirtualCenter server, see How to Add a VMware VirtualCenter Server (http://go.microsoft.com/fwlink/?LinkID=128560).
Considerations When Adding Hosts
VMM administrators cannot use the same domain account that is used as the VMM service account to add or remove a Hyper-V or Virtual Server host from VMM. For information about improving the security of hosts, see Hardening Virtual Machine Hosts Managed by VMM (http://go.microsoft.com/fwlink/?LinkID=145057).
When you add a Windows-based host, VMM automatically installs or enables the appropriate version of virtualization software on the host and attempts to create a Windows Firewall exception, if needed.
When you add a host to VMM and the host’s operating system supports Hyper-V, if Hyper-V is not enabled on the host, VMM will attempt to enable it automatically.
|Enabling the Hyper-V role will cause the host to immediately restart. If the host you are adding is the VMM server, restarting it will stop any jobs that are running and you must add the host again after the Hyper-V role has been enabled.|
When you add a host to VMM and that host's operating system supports Virtual Server 2005 R2 SP1, VMM automatically installs the correct version of Virtual Server 2005 R2 if it is not installed already.
If your VMM implementation has over 150 hosts, we strongly recommended that you enable server-optimized garbage collector (GC) on the VMM server instead of the default workstation garbage collector. This can significantly reduce the CPU utilization on the VMM server and improve your performance for parallel VMM operations.
To enable server-optimized garbage collector (GC) on the VMM server, create a file that is named
vmmservice.exe.config by using the following code, and then for VMM 2008, place it into the %SYSTEMDRIVE%\Program Files\Microsoft System Center Virtual Machine Manager 2008\Bin directory on the VMM server, or for VMM 2008 R2, place it into the %SYSTEMDRIVE%\Program Files\Microsoft System Center Virtual Machine Manager 2008 R2\Bin directory on the VMM server.
<configuration> <runtime> <gcServer enabled="true"/> </runtime> </configuration>
Virtual Machine Default Paths
When you add a stand-alone Windows Server-based virtual machine host to Virtual Machine Manager (VMM), you can add one or more virtual machine default paths, which are paths to folders where VMM can store the files for virtual machines that are deployed on the hosts.
|Adding a default path on a host in the Add Hosts Wizard does not automatically create the folder on the host. You must manually create the folder at the specified path before you can use the path in VMM to store virtual machine files on the host.|
For a host cluster, either Windows Server-based or VMware-based, the default path is a shared volume on the cluster that VMM automatically creates when you add the host cluster. When you are adding the host cluster, you cannot specify additional default paths in the Add Hosts Wizard. Also, after a host cluster has been added, you cannot specify additional default paths on the Placement tab of the host properties.
After you have added a stand-alone Windows Server-based host, you can add or remove default paths on the host. For more information, see How to Set Placement Options for a Host.
For more information about virtual machine default paths, see About Default Virtual Machine Paths (http://go.microsoft.com/fwlink/?LinkId=162784).
Hosts on Perimeter Networks
You must manually install a VMM agent on a host on a perimeter network before you can add it to VMM. When you install a VMM agent on the host, the VMM Agent Setup Wizard creates a local agent service account that is named SCVMMxxxxxxxxxx (where xxxxxxxxxx is a sequence of random letters and numbers) and generates a random password. The VMM server uses this account to communicate with the host. After some time, depending on your Group Policy, the password might expire for this auto-generated account (or for another account that you might have used instead), and the VMM server will no longer be able to communicate with the host. When this occurs, in the VMM Administrator Console, in Hosts view, the host will have a Status of Needs Attention, and in Administration view, in Managed Computers, the host will have an Agent Status of Access Denied. To avoid or correct this, you must change the credentials for the agent on the Credentials tab of the Host Properties dialog box. For more information, see How to Set Credentials for Communicating with a Host.
In VMM 2008, virtual machines that have been deployed on a host on a perimeter network cannot be migrated to hosts in the internal network or to other hosts on a perimeter network. In VMM 2008 R2, virtual machines that have been deployed on a host on a perimeter network cannot be migrated to hosts in the internal network, but can be migrated to other hosts on a perimeter network.
You can create custom groups of virtual machine hosts, known as host groups, for grouping hosts and their virtual machines in a meaningful way. You can also use host groups to set aside resources, known as host reserves, for all hosts in the host group for the use of the host operating system. For any given host in a host group, you can override the host reserves settings that were made at the host group level.
Host groups are hierarchical. You can create a child host group within another host group. All host groups and all hosts belong to the All Hosts root host group, which is created during the installation of VMM.
For more information about host groups, see About Host Groups.
In VMM 2008 R2, you can allow unencrypted file transfers by selecting the Allow unencrypted file transfers check box. During future file transfers to and from hosts in the host group, the files will not be encrypted if unencrypted file transfers are allowed in VMM both on the source computer (a host, library server, or P2V source machine) and the destination computer (either a host or a library server). During physical-to-virtual machine conversions (P2V), unencrypted file transfers from the P2V source machine always are allowed if they also are allowed on the destination host.
You can use the tabs in the Host Properties dialog box to view or modify the properties of a host, such as adding or modifying virtual networks, setting placement options, or setting host reserves. To open the Host Properties dialog box, in the VMM Administrator Console, in Hosts view, right-click a host, and then click Properties. For more information about modifying host properties, see Modifying the Properties of a Host (http://go.microsoft.com/fwlink/?LinkId=163331).
To optimize the performance of virtual machine hosts, it is recommended that you dedicate one or more hosts to be used as maintenance hosts. A maintenance host is a host that you use only for virtual machine maintenance tasks, such as patching stored virtual machines and templates or staging scripted virtual machine creation before moving the virtual machines into your production environment. By using a dedicated host to perform virtual machine maintenance tasks, you can avoid affecting the performance and host rating of a production host while performing such tasks.
|A maintenance host should not be confused with a host that you place into maintenance mode, described in a later section.|
For more information about maintenance hosts, see About Maintenance Hosts.
In VMM 2008 R2, you can start maintenance mode for a Windows-based virtual machine host anytime that you need to perform maintenance tasks on the physical host, such as applying security updates or replacing hardware on the physical host computer. For more information about maintenance mode, see About Maintenance Mode.