Windows Server 2008 R2 : Deploying and Using Windows Virtualization - Quick Migration and Live Migration (part 3)

3/29/2011 3:39:16 PM

Deploying New Virtual Machines on CSV Failover Clusters

After the desired cluster configuration is achieved, the cluster is ready for the deploying of virtual machines:

1.	On one of the cluster nodes, open Failover Cluster Management.
2.	Expand the Cluster and select Services and Applications.
3.	Now that Cluster Storage Volumes have been configured, the Virtual Machines application is available in the Actions pane. Click Virtual Machines, New Virtual Machine and select the cluster node on which to deploy the virtual machine.
4.	The New Virtual Machine Wizard will launch. Click Next at the introduction screen.
5.	Provide a name for the new virtual machine and click the Store the Virtual Machine in a Different Location check box. Enter the path to the C:\ClusterStorage\Volume1, as shown in Figure 5, and click Next. Figure 5. Specify the name and location of the virtual machine. Note It is recommended on Hyper-V servers using Live Migration to change the default location to store virtual machines to the Cluster Shared Volume path. This is configured in Hyper-V Settings of the Hyper-V Manager console.
6.	Assign the desired amount of memory for the new virtual machine.
7.	Select the virtual network, or choose Not Connected to configure it later. Click Next.
8.	Create a new virtual hard disk in the C:\ClusterStorage\Volume1 folder or select an existing VHD and click Next. Note Both the virtual machine configuration file and its associated virtual hard disk (VHD) files must reside in the CSV folder location for Live Migration to work.
9.	Select how you will install the operating system for the new virtual machine, either using a boot CD-DVD ROM, ISO image, floppy disk, or from a network-based installation server, and click Next.
10.	Review the summary of the options you have selected and either click Finish if the settings you’ve chosen are fine, or click Previous to go back and make changes.
11.	Click Finish to create the new virtual machine. After the virtual machine is saved to the CSV path, the High Availability Wizard will configure the virtual machine for use in Live Migration, as shown in Figure 6. Click View Report to review the step the High Availability Wizard used to configure the virtual machine for Live Migration. Figure 6. The High Availability Wizard. Note It is normal for the High Availability Wizard to report a warning if the operating system for the virtual machine will be installed from the host’s physical CD-DVD ROM, an ISO file, or a floppy drive. This is because the drive or file used for installation is not in a location available to the cluster. Most of the time, this does not matter, but it can be overcome if needed by installing the operating system from an ISO located on the CSV location.
12.	Click Finish to complete the configuration of the new virtual machine.
13.	Change the virtual machine settings, if desired, to increase the number of virtual processors, change the drive configuration, and so on.
14.	Right-click the virtual machine in Failover Cluster Manager and select Start Virtual Machines to start the virtual machine and install the operating system.

Once the operating system is installed, Live Migration can be used to move the cluster from one node to another.

Deploying Existing Virtual Machines on CSV Failover Clusters

If the LUN provisioned as a CSV disk in the cluster contains existing virtual machine images, these can be made highly available. You can also copy any virtual hard disk to the CSV volume and make it highly available:

1.	On one of the cluster nodes, open Failover Cluster Management.
2.	Expand the cluster and select Services and Applications.
3.	Right-click Services and Applications and select Configure a Service or Application. This will open the High Availability Wizard.
4.	Click Next on the Before You Begin page.
5.	On the Service or Application page, click Virtual Machine and click Next.
6.	Select the virtual machine(s) to be made highly available and click Next.
7.	Review the Summary page in the wizard and click Finish.
8.	Select the virtual machine in the Service and Application pane and click Start Virtual Machines in the Actions pane.

Performing a Live Migration

The virtual machine runs on one of the cluster nodes, known as the owner. When a Live Migration is performed, multiple steps are performed. These steps can be broken down into three stages: preflight migration, virtual machine transfer, and final transfer/startup of the virtual machine.

The first step in Live Migration occurs on the source node (where the virtual machine is currently running) and the target node (where the virtual machine will be moved) to ensure that migration can, in fact, occur successfully.

The detailed steps of Live Migration are as follows:

1.	Identify the source and destination machines.
2.	Establish a network connection between the two nodes.
3.	The preflight stage begins. Check if the various resources available are compatible between the source and destination nodes: Are the processors using similar architecture? (For example, a virtual machine running on an AMD node cannot be moved to an Intel node, and vice versa.) Are there a sufficient number of CPU cores available on the destination? Is there sufficient RAM available on the destination? Is there sufficient access to required shared resources (VHD, network, and so on)? Is there sufficient access to physical device resources that must remain associated with the virtual machine after migration (CD drives, DVDs, and LUNs or offline disks)? Migration cannot occur if there are any problems in the preflight stage. If there are, the virtual machine will remain on the source node and processing ends here. If preflight is successful, migration can occur and the virtual machine transfer continues.
4.	The virtual machine state (inactive memory pages) moves to the target node to reduce the active virtual machine footprint as much as possible. All that remains on the source node is a small memory working set of the virtual machine. The virtual machine configuration and device information are transferred to the destination node and the worker process is created. Then, the virtual machine memory is transferred to the destination while the virtual machine is still running. The cluster service intercepts memory writes and tracks actions that occur during the migration. This page will be retransmitted later. Up to this point, the virtual machine technically remains on the source node.
5.	What remains of the virtual machine is briefly paused on the source node. The virtual machine working set is then transferred to the destination host, storage access is moved to the destination host, and the virtual machine is reset on the destination host.

The only downtime on the virtual machine occurs in the last step, and this outage is usually much less than most network applications are designed to tolerate. For example, an administrator can be accessing the virtual machine via Remote Desktop while it is being Live Migrated and will not experience an outage. Or a virtual machine could be streaming video to multiple hosts, Live Migrated to another node, and the end users don’t know the difference.

Use the following steps to perform a Live Migration between two cluster nodes:

1.	On one of the cluster nodes, open Failover Cluster Management.
2.	Expand the Cluster and select Services and Applications.
3.	Select the virtual machine to Live Migrate.
4.	Click Live Migrate Virtual Machine to Another Node in the Actions pane and select the node to move the virtual machine to. The virtual machine will migrate to the selected node using the process described previously.

Note

If there are processor differences between the source and destination node, Live Migration will display a warning that the CPU capabilities do not match. To perform a Live Migration, you must shut down the virtual machine and edit the settings of the processor to “Migrate to a Physical Computer with a Different Processor Version”.