Adding and Configuring Hosts
A virtual machine host is a physical computer that hosts one or more virtual machines. You can use System Center Virtual Machine Manager (VMM) to manage virtual machines on hosts in a trusted domain or on a perimeter network.
You must add at least one virtual machine host to VMM.
Adding Hosts in Trusted Domains
You can use the Add Hosts Wizard in the VMM Administrator Console to add one or more virtual machine hosts to VMM if all the hosts are in a trusted AD DS domain. You also can use the Add Hosts Wizard to discover existing hosts that are in a trusted AD DS domain and then decide which hosts you want to add.
When you add a host by using the Add Hosts Wizard, VMM automatically installs a VMM agent and, if needed, installs Virtual Server 2005 R2 with Service Pack 1 on the host. For more information about adding hosts in a trusted domain, see the "How to Add Hosts in a Trusted Domain" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=102048).
Adding Hosts on a Perimeter Network
Before you can add the host by using the Add Hosts Wizard in the VMM Administrator Console, you must install a VMM agent locally on the host.
For more information about installing a VMM agent on a host on a perimeter network, see Installing a VMM Agent Locally.
When you install a VMM agent locally on a host on a perimeter network, the Agent Setup Wizard prompts you for an encryption key and other information needed by VMM to access and manage the host and its virtual machines. The wizard generates a local account with administrator privileges on the host and a set of credentials for the account and uses the key to encrypt the credentials and the other agent access information into a security file.
After you have installed an agent locally on the host, you use the security file to add the host by using the Add Hosts Wizard in the VMM Administrator Console. For more information about adding hosts on a perimeter network, see the "How to Add a Host on a Perimeter Network" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=98818).
You need to configure each host to best match your environment and virtualization objectives. This section explains the host configuration tasks you can perform. You configure a host by modifying its properties. For step-by-step instructions for modifying host properties, see the "Modifying the Properties of a Host" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=103128).
Configuring Virtual Networks
When Virtual Server is installed on a host, Virtual Server Setup automatically creates an internal virtual network that enables networking between virtual machines running on the host. Virtual Server Setup also creates one external virtual network for each physical network adapter that is installed on the host.
Each virtual network is implemented in a separate virtual network configuration (.vnc) file. The location of the configuration files for the networks created by Setup is %SYSTEMDRIVE%\Documents and Settings\All Users\Documents\Shared Virtual Networks.
|Your backup plan for VMM should include any virtual network configuration files that you create. For more information about backing up VMM, see the "Backing Up Virtual Machine Manager" topic in Operations (http://go.microsoft.com/fwlink/?LinkId=103031).|
Depending on the needs of your organization, these virtual networks might be the only ones that you need, or you might need to add and configure additional virtual networks.
For step-by-step instructions for adding and configuring a virtual network, see the "How to Configure Virtual Networks on a Host" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=98838).
Virtual Network Names
When Virtual Server Setup automatically creates an external virtual network, it assigns a network name based on the system name of the network adapter. For example, a virtual network might be named External Network (Intel(R) PRO_1000 MT Network Connection).
Virtual network names are essential in the placement and migration of virtual machines. To facilitate the placement and migration of virtual machines, you should change the external virtual network names to ones that are more meaningful and descriptive of the networks that each adapter is connected to and make those names consistent across all hosts.
Virtual Network Names in Placement and Migration
During placement and migration, hosts are rated based on their ability to meet the virtual machine’s resource requirements and the availability of the host's resources, including network connectivity. For more information about host ratings, see the "About Host Ratings" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=100580).
If a virtual machine is associated with a particular virtual network, VMM attempts to identify destination hosts that have the same virtual network to maintain connectivity for the virtual machine. To make this determination, VMM compares the virtual network names and descriptions based on the following criteria:
If the virtual network name that the virtual machine is associated with is identical to a virtual network name on a destination host, VMM assumes that the underlying network is the same. After the virtual machine is on the destination host, VMM automatically attempts to reconnect the virtual machine to that network.
Important To maintain network connectivity during placement and migration, virtual network names should be consistent across all hosts.
If no hosts with identical virtual network names are found, VMM next compares the virtual network descriptions. If the virtual network descriptions are identical, VMM assumes that the underlying networks are the same. After the virtual machine is on the destination host, VMM automatically attempts to reconnect the virtual machine to that network. Blank descriptions are ignored for this comparison.
If neither the virtual network name nor the description is identical, VMM assumes that there are no matching virtual networks and the host receives a zero rating.
If a virtual machine is associated with more than one network, VMM attempts to match and reconnect to all networks. If all the networks for the virtual machine cannot be matched on a destination host, the host receives a zero rating. You can still deploy or migrate the virtual machine to the host; however, VMM does not automatically reconnect the virtual machine to any of the virtual networks of the host.
For information about virtual networks during placement for a clustered host, see "Managing Virtual Server Host Clustering with System Center Virtual Machine Manager 2007" at http://go.microsoft.com/fwlink/?LinkId=98888.
Configuring Placement Settings
When you deploy or migrate a virtual machine on a host, the process of selecting the most suitable host is known as virtual machine placement, or simply placement. During placement, VMM assigns each available host a host rating of 0–5 to indicate the host's suitability for hosting the virtual machine. The ratings include the placement settings for virtual machines, the resources available on the hosts, and the hardware and resource requirements for the specific virtual machine.
Virtual machine placement settings consist of either of these placement goals:
Resource maximization on an individual host.
Load balancing among hosts, and the resource importance settings for CPU utilization, memory, disk space, and network utilization.
You can customize these ratings to address the unique requirements of an individual virtual machine as you deploy or migrate the virtual machine. For step-by-step instructions for configuring the default placement settings, see the "How to Set Placement Defaults for Virtual Machines" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=100583).
In the following cases, a virtual machine is automatically placed on the most suitable host in a host group, in a process known as automatic placement:
In virtual machine self-service, users' virtual machines are automatically placed on the most suitable host in the host group that is used for self-service.
When the drag-and-drop method is used to migrate a virtual machine to a host group in Virtual Machines view.
During automatic placement, the virtual machine files are moved to the virtual machine default path on the host that has the most available space on its volume.
Configuring Placement Options for a Host
In addition to the systemwide placement settings, there are placement options that you can configure for each host as described in this section. These settings include:
Adding Virtual Machine Default Paths
When Virtual Server is installed on a host, Virtual Server Setup automatically creates a virtual machine path at %SYSTEMDRIVE%\Documents and Settings\All Users\Documents\Shared Virtual Machines.
You can add one or more virtual machine default paths on which to store the files for virtual machine that are deployed on the host. You should create at least one default path on any volume on which you want to deploy virtual machines.
When you deploy or migrate a virtual machine by using the New Virtual Machine Wizard, Deploy Virtual Machine Wizard, or Migrate Virtual Machine Wizard, you can select either a default path for the virtual machine or specify a different path.
Both virtual machine self-service and drag-and-drop migration employ automatic placement, in which the virtual machine files are moved to a default path on the volume with most available space.
Designating Maintenance Hosts
You can designate one or more hosts as a maintenance host. A maintenance host is a host that you can dedicate for updating virtual machines and for staging virtual machines before moving them into your production environment.
By using a dedicated host to perform maintenance tasks, you can avoid affecting the performance and the host rating of a production host while performing such tasks.
The maintenance host designation is for reference only; however, by also making a maintenance host unavailable for placement, you can reduce the possibility of other virtual machines being placed on the host during automatic placement.
Removing a Host from Placement
If you do not want a host to be considered for placement by VMM, for instance if you are using it as a maintenance host, you can remove the host from placement.
For step-by-step instructions about modifying placement options for a host, see the "How to Set Placement Options for a Host" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=102860).
Configuring Virtual Machine Remote Control (VMRC)
Virtual Machine Remote Control (VMRC) is a feature of Virtual Server 2005 that you can enable, disable, and configure from within Virtual Machine Manager (VMM).
By default, when you add a host to VMM, VMRC is enabled on the host with default settings but encryption for VMRC connections is not enabled.
|It is a best practice to not use default settings. If you change the VMRC port, the port setting you assign for the host must identically match the VMRC port setting that is assigned in Virtual Server.|
You can use Secure Sockets Layer (SSL) to encrypt communications over the VMRC connection by uploading a certificate from an appropriate internal or non-Microsoft certification authority (CA).
|It is a best practice to implement Secure Sockets Layer (SSL) security for Virtual Machine Remote Control (VMRC) connections, particularly if you use Basic authentication, which transmits passwords in plaintext.|
For more information about VMRC, see the "About Virtual Machine Remote Control (VMRC)" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkID=103123).
You can configure VMRC settings when adding a host by using the Add Hosts Wizard, with the exception of encryption settings, or you can configure VMRC settings after you add a host. For step-by-step instructions about configuring VMRC settings for a host, see the "How to Modify VMRC Settings on a Host" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=102194).
Configuring Custom Properties
The host properties provide you with 10 user-configurable custom fields that you can use in any manner you want. For example, you might use custom fields to identify, track, and sort hosts into various categories, such as by department, by geographic area, or by function (for example, development, test, or production). One example of how this feature might be helpful is if you need to track the use of virtual machines for the purposes of allocating the usage costs back to the end-user departments.
After adding custom properties to a host, you can add columns for the custom properties to the results pane in Hosts view and then click the column header for a custom property column to sort your virtual machines by that property. For step-by-step instructions for configuring custom properties for a host, see the "How to Add and Display Custom Properties for a Host" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkID=103156).
Registering Virtual Machines on a Host
If you have virtual machine configuration files (vmc) on shared storage that have not previously been registered with Virtual Server, you can use Virtual Machine Manager to register the files on a host to create virtual machines.
After you have registered virtual machine configuration files, VMM discovers the virtual machines automatically. For step-by-step instructions for registering virtual machines on a host, see the "How to Register Virtual Machines on a Host" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=98836).
Setting the Agent Password for a Host on a Perimeter Network
To access and control a host on a perimeter network, VMM uses a local account with administrator privileges, which the Agent Setup Wizard creates automatically when you install an agent locally on the host. You cannot change the credentials for the local account during setup; however, you can set a different password after you have added the host.
For step-by-step instructions for setting the agent password, see the "How to Set the Agent Password for a Host on a Perimeter Network" topic in VMM Help (http://go.microsoft.com/fwlink/?LinkId=103304).