Creating a new virtual machine from an existing virtual hard disk

Due to numerous requests, I dedicate this entry to talk about creating a virtual machine from an existing virtual hard disk. It seems that some of you were not able to get it working using the example of adding a DVD as resource to an existing VM. I must admit that it's not intuitive and I still have to do it several times to make it right.
Note:  The script is tested against Hyper-V RC1.

 

Goal

Create a new virtual machine based on an existing virtual hard disk. The VHD file is called C:\W2K3.VHD and the disk will be created on IDE Controller 0 at location 0.

High level steps

1. Create a new virtual machine
2. Locate the IDE Controller 0
3. Get the default Disk Drive instance. Create a new instance from the default one. Attach it to the IDE Controller 0 at location 0. Add the disk drive as new resource to the VM
4. Get the default virtual hard disk instance. Create a new instance from the default one. Attach it to the disk drive. Connect it to the VHD file. Add the disk drive as new resource to the VM

Script

$VHDFile = "C:\W2K3.vhd"

# Step 1

$VM_Service = get-wmiobject –namespace root\virtualization Msvm_VirtualSystemManagementService
$status = $VM_Service.DefineVirtualSystem()

if ($status.ReturnValue -eq 0)
{
    $NewVM_PATH = $status.DefinedSystem
}

# Step 2

$ListOfControllers = get-wmiobject -namespace root\virtualization Msvm_ResourceAllocationSettingData `
                                    | where {$_.ResourceSubType -like "*Emulated*IDE*"}
foreach ($Controller in $ListOfControllers)
{
            if ($Controller.Address -eq 0)
            {
            # It must return exactly one controller. Let's assume that is the case
            $IDEController0 = $Controller
            }
}

# Step 3

$DiskDefault = get-wmiobject -namespace root\virtualization Msvm_ResourceAllocationSettingData | `
                 where {($_.ResourceSubType -like "Microsoft Synthetic Disk Drive") –and   `
                 ($_.InstanceID -like '*Default*')}  

$DiskDrive = $DiskDefault.psbase.Clone()
$DiskDrive.Parent = $IDEController0.__PATH          # Attach to IDE Controller 0
$DiskDrive.Address = 0                                                 # at Location 0
$Status = $VM_Service.AddVirtualSystemResources($NewVM_PATH, $DiskDrive.psbase.GetText(1))
if ($Status.ReturnValue –eq 0)
{
             $NewDiskDrive_PATH = $Status.NewResources
}

# Step 4

$VHDDefault = get-wmiobject -namespace root\virtualization Msvm_ResourceAllocationSettingData | `
                 where {($_.ResourceSubType -like "Microsoft Virtual Hard Disk") –and `
                 ($_.InstanceID -like '*Default*' )}  

$NewDiskDrive = [WMI]"$NewDiskDrive_PATH"
$VHDisk = $VHDDefault.psbase.Clone()
$VHDisk.Parent = $NewDiskDrive.__PATH            # Attach to the disk drive
$VHDisk.Connection = $VHDFile
$VM_Service.AddVirtualSystemResources($NewVM_PATH, $VHDisk.psbase.GetText(1))

 

Enjoy!

/Dung

HyperV WMI PowerShell

 

Hyper-V Virtual Networks - Connecting virtual machines to a virtual network

Now that you know how to create virtual networks, let me show how to connect a NIC of a given virtual machine to a network

The script below is extracted from a discussion in the Virtualization Technet Forum. All credits go to AggieMatt!

## Assumes that  you already identify a virtual switch and store it in a variable called $Switch

## Create a new SwitchPort
$VSwitch_Mgmt = gwmi -namespace root/virtualization Msvm_VirtualSwitchManagementService
$VSwitch = gwmi -namespace root/virtualization Msvm_VirtualSwitch
$PortName = "MyPortName"
$Scope = ""
$Status = $VSwitch_Mgmt.CreateSwitchPort($VSwitch, $PortName, $PortName, $Scope)
$NewPortPath = $Status.CreatedSwitchPort
## Add a new SyntheticEthernetPort
$DefaultNIC = gwmi -namespace root/virtualization Msvm_SyntheticEthernetPortSettingData | where {$_.InstanceID -like "*Default*"}
$NewSyntheticNIC = $DefaultNIC.psbase.Clone()
$NewSyntheticNIC.Connection = $NewPortPath
$NewSyntheticNIC.ElementName = "Network Adapter"
$SyntheticNICGUID = [guid]::NewGuid().ToString()
$NewSyntheticNIC.VirtualSystemIdentifiers = "{" + $SyntheticNICGUID + "}"
## Apply the settings to the selected computer
$VM_Mgmt = get-wmiobject -namespace root\virtualization Msvm_VirtualSystemManagementService
$VMName = "MyVMName"
$VM = get-wmiobject -namespace root\virtualization Msvm_ComputerSystem | where {$_.ElementName -like $VMName}
$VM_Mgmt.AddVirtualSystemResources($VM.__PATH, $NewSyntheticNIC.psbase.gettext(1))

Enjoy!

/Dung

HyperV WMI PowerShell

 

Hyper-V Virtual Networks - Creating External Virtual Networks

Finally let's see how you can create an External virtual network. Here is an overview of high level steps:

External Virtual Network

1. Find the Msvm_ExternalEthernetPort instance associated to a physical network adapter
2. Call CreateSwitch to create a virtual network.
3. Call CreateSwitchPort  to create at least 2 ports on the switch
4. Call SetupSwitch  to create an external virtual network

Script

# Step 0: Connect to the Virtual Network Management Service
$SW_Service = get-wmiobject –namespace root\virtualization Msvm_VirtualSwitchManagementService

# Step 1
$ThisPhysicalAdapter = get-wmiobject -namespace root\virtualization msvm_ExternalEthernetPort -filter "Name = 'Broadcom BCM5708C NetXtreme II GigE (NDIS VBD Client) #2' "

## Change the name used above to the name of your network adapter.

# Step 2
$Status = $SW_Service.CreateSwitch("External_Network", "External Virtual Network", 1024, "")

# Store the path for later use
$External_SwitchPATH = $Status.CreatedSwitchService

# Step 3: Create two ports on the switch
# Port for Internal
$Status = $SW_Service.CreateSwitchPort($External_SwitchPATH, "Internal_Port" , "Internal Port for Host")

# Store the path for later use
$InternalSwitchPortPATH = $Status. CreatedSwitchPort

# Port for External
$Status = $SW_Service.CreateSwitchPort($External_SwitchPATH, "External_Port" , "External Port")

# Store the path for later use
$ExternalSwitchPortPATH = $Status. CreatedSwitchPort

# Step 4
$Status = $SW_Service.SetupSwitch($ExternalSwitchPortPATH, $InternalSwitchPortPATH, $ThisPhysicalAdapter, "Internal Network Adapter", "Internal NIC to External Virtual Network")

Enjoy!

/Dung

HyperV WMI PowerShell

 

Hyper-V Virtual Networks - Creating Internal Virtual Networks

Let's talk about how to create Internal Virtual Networks. In my previous post, I described the concept and high level steps to create internal virtual network.

Steps to create a Internal Virtual Network

1. Call CreateInternalEthernetPort to create a virtual NIC on the Hyper-V host system.
2. Find the LAN Endpoint  associated to this virtual NIC by querying Msvm_LANEndPoint
3. Call CreateSwitch to create a virtual network.
4. Call CreateSwitchPort  to create at least one port on the switch
5. Call ConnectSwitchPort to connect the port with the LAN Endpoint

Script

$SW_Service = get-wmiobject –namespace root\virtualization Msvm_VirtualSwitchManagementService

## Step 1

$Status = $Sw_Service.CreateInternalEthernetPort("Internal Network Adapter", "Internal NIC", "020304050607" )

if ($Status.ReturnValue -eq 0)

{
write-host "Internal Ethernet Port successfully created"
$InternalEtherPortPATH = $Status.CreatedInternalEthernetPort
}

## Step 2

$NIC_Port = [WMI]$InternalEtherPortPATH
# Get the name of this NIC
$NIC_Name = $NIC_Port.Name

# Find the LANEndPoint associated to this NIC
$LANEndPoint = get-wmiobject -namespace root\virtualization Msvm_LanEndPoint -filter "Name = `'$($NIC_Name)`'"

## Step 3

$Status = $SW_Service.CreateSwitch(“Internal_Network”, “Host and Guests Virtual Network”, 1024, “”)

if ($Status.ReturnValue -eq 0)

{
write-host "Switch successfully created"
$SwitchPATH = $Status.CreatedSwitchService
}

## Step 4

$Status = $SW_Service.CreateSwitchPort($SwitchPATH, "Internal_Port" , "Internal Port for Host")

if ($Status.ReturnValue -eq 0)

{
write-host "SwitchPort successfully created"
$PortPATH = $Status.CreatedSwitchPort
}

## Step 5

$Status = $SW_Service.ConnectSwitchPort($PortPATH , $LANEndPoint)

## Additional Step - Create a port to connect VM

$Status = $SW_Service.CreateSwitchPort($SwitchPATH, "One_Port" , "A Switch Port to connect VM")

if ($Status.ReturnValue -eq 0)

{
write-host "SwitchPort successfully created"
$PortPATH = $Status.CreatedSwitchPort
}

 

Enjoy!

/Dung

 HyperV WMI PowerShell

Hyper-V Virtual Networks - Creating Private Virtual Networks

In a previous post, I give you an overview of virtual networks and high-level steps to create virtual networks. Let's put it in practice today and show how to create a private virtual network.

Steps to create a Private virtual network

1. Call CreateSwitch to create a virtual network. By default, this method creates a private virtual network
2. Call CreateSwitchPort  to create ports on the switch

Script

$SW_Service = get-wmiobject –namespace root\virtualization Msvm_VirtualSwitchManagementService

# Call CreateSwitch
# 1024 represents the max number of MAC addresses learnable by the switch
# The 4^th parameter represents the scope of residence and is not currently defined and used

$Status = $SW_Service.CreateSwitch(“Private_Network”, “Guest only Virtual Network”, 1024, “”)

if ($Status.ReturnValue -eq 0)

{
write-host "Switch successfully created"
$SwitchPATH = $Status.CreatedSwitchService
}

## Create a SwitchPort

$Status = $SW_Service.CreateSwitchPort($SwitchPATH, "One_Port" , "A Switch Port to connect VM")

if ($Status.ReturnValue -eq 0)

{
write-host "SwitchPort successfully created"
$PortPATH = $Status.CreatedSwitchPort
}

 

Enjoy!

/Dung

 HyperV WMI PowerShell

 

Hyper-V Virtual Networks

Up to now, we've spent a significant amount of time and blog entries to talk about virtual machines. Let's switch gear and discuss about virtual networks.

Networking Concepts

In Hyper-V, you create virtual networks and connect virtual network cards (NICs) of virtual machines to allow communications between the machines themselves, the host system and eventually the physical network.

A virtual network, also called Virtual Switch can be one of the three following types:

· Private: Virtual machines connected to this network can communicate between them. The host system has no connectivity with virtual machines

· Internal: Virtual machines connected to this network can communicate between themselves and the host system. There is no connectivity with the physical network.

· External: An external virtual network binds to the physical network adapter so that virtual machines as well as the host system can access the physical network.

Virtual networks and connections of virtual machines to virtual networks are managed by a Hyper-V service called Virtual Switch Management Service. There is a WMI class associated to this service called Msvm_VirtualSwitchManagementService.

 

Private Virtual Network

When you create a private virtual network, the Virtual Network Manager Service running on the host system will create a Virtual Switch and allows you to connect virtual machines to this switch. The host system does not participate in this private network, as such, cannot communicate with virtual machines connected to it. This type of network is also known as "Guest-Only Network" or "Private Virtual Machine Network". The figure below shows a visual representation of a private virtual network.

 

 

 

 

 

 

 

 

 

 

 

Internal Virtual Network

When you create an Internal virtual network, the Virtual Network Manager Service running on the host system will create:

· A virtual network

· A virtual NIC on the host system that will be connected to the virtual network.

As such, all virtual machines connected to the Internal virtual network can communicate with the host system and vice-versa. It is important to note that existing physical network adapters are left untouched. The figure below shows a visual representation of an internal virtual network.

 

 

 

External Virtual Network

When you create an External virtual network, you specify a physical network adapter for the virtual network to bind to. As a consequence, the Virtual Network Manager Service running on the host system will create:

· A virtual network

· A virtual NIC on the host system that will be connected to the virtual network

The physical network adapter will then be connected to the virtual network. The latter will be acting as a router and allow both virtual machines and host system to connect to the physical network. Figure 3 illustrates the concept of an external virtual network.

It's interesting to note that:

• all the existing network connections to the host system will be lost as soon as you create an external virtual network that binds to a unique physical NIC of the host system. The host is now “connected” to the physical network through the virtual NIC and the virtual “switch”
• You cannot create an external virtual networks that is bound to a wireless adapter.

The figure below illustrates the concept of an external virtual network.

 

 

How to connect a virtual machine to a virtual network?

Now that you understand the concept of virtual network, your next question would be to connect a virtual machine to a virtual network.

Assume that your virtual machine already has a NIC and that you have created a virtual network, you will need to create a port on the virtual network, or to be exact, create a SwitchPort, and then associate this SwtichPort to a NIC by setting  the Connection property of the NIC to the WMI Path of the SwitchPort.

If your virtual machine does not have a NIC, you need to create one by duplicating the default instance of Msvm_SyntheticEthernetPortSettingData and perform the same operations as above.

Overview of Msvm_VirtualSwitchManagementService

The Msvm_VirtualSwitchManagementService class is used to control the creation and configuration of virtual networks. As you can see from the explanations above, there are two distinct tasks in virtual networks management. First you create a virtual network and define its type – private, internal, external. Once the virtual network created, you then create ports on the switch for network connections. Second you connect virtual NICs (either from virtual machines or the host system) to a virtual network. The Msvm_VirtualSwitchManagementService class provides several methods to create virtual networks and configure its type. Creating a virtual network is very easy and consists of a single-step operation. To configure the type, you may need additional steps.

Here is a high-level overview of steps to create and configure virtual networks. All the methods listed below come from the Msvm_VirtualSwitchManagementService class.

Private Virtual Network

1. Call CreateSwitch to create a virtual network. By default, this method creates a private virtual network
2. Call CreateSwitchPort  to create ports on the switch

Internal Virtual Network

1. Call CreateInternalEthernetPort to create a virtual NIC on the Hyper-V host system.
2. Find the LAN Endpoint  associated to this virtual NIC by querying Msvm_LANEndPoint
3. Call CreateSwitch to create a virtual network.
4. Call CreateSwitchPort  to create at least one port on the switch
5. Call ConnectSwitchPort to connect the port with the LAN Endpoint

 

External Virtual Network

1. Find the Msvm_ExternalEthernetPort instance associated to a physical network adapter
2. Call CreateSwitch to create a virtual network.
3. Call CreateSwitchPort  to create at least 2 ports on the switch
4. Call SetupSwitch  to create an external virtual network

That's it!

Until next time...

/Dung

 HyperV WMI PowerShell

 

Adding Resources of a VM

To continue from the previous post, let's discuss how you can add a resource to a VM. In this scenario, I want to add a new DVD drive to my VM virtual machine and attach an ISO file called c:\ISO\W2K3.ISO.

When you explore settings of a given VM using the Hyper-V Manager console, you notice that a VM can have up to 2 IDE controllers (0,1) and each IDE controller has 2 slots (0,1). You can add either a disk drive or a DVD drive to each of the IDE controllers.

You also notice that you can only add a drive (disk or DVD) when selecting a controller and cannot use the generic action "Add Hardware" to add a drive. The script should behave exactly like the GUI interface, meaning that I have to provide the IDE controller number and slot as parameters when creating a drive.

Enough talk , let's do real work :=)

Note:  Script updated based on James Logan's feedback.

Assume that I want to add a DVD drive to my VM on IDE Controller 1 at location 1

-------------------Start of Script to Add a resource ------------------------------------------------

VM_Service = get-wmiobject -namespace root\virtualization Msvm_VirtualSystemManagementService
$VM = gwmi -namespace root\virtualization Msvm_ComputerSystem | where {$_.ElementName -like "My VM"}

# Step 1; Locate an IDE controller and an available location 

$ListOfControllers = get-wmiobject -namespace root\virtualization Msvm_ResourceAllocationSettingData | `
                          where {$_.ResourceSubType -like "*Emulated*IDE*"}

foreach ($Controller in ListOfControllers)
{

            if ($Controller.Address -eq 1)
            {
             # It must return exactly one controller. Let's assume that is the case
             $IDEController1 = $Controller
             }
}

# Step 2: Create a synthetic DVD drive
# Now we create a new DVD drive. To create a new drive you will search for the Default instance object and clone it.

$DVD_Default = get-wmiobject -namespace root\virtualization Msvm_ResourceAllocationSettingData | `
                          where {($_.ResourceSubType -like "Microsoft Synthetic DVD Drive") -and ($_.InstanceID -like '*Default*'" )}  

$NewDVDDrive = $DVD_Default.psbase.Clone()

## So fill out the necessary information

$NewDVDDrive.Parent = $IDEController1.__PATH

$NewDVDDrive.Address = 1              

## Apply the changes

$VM_Service.AddVirtualSystemResources($VM.__PATH, $NewDVDDrive.psbase.Gettext(1))

  #Step 3: Create a CD/DVD disk

# First locate the new DVD drive created in previous step.
# Note: There must be a more elegant way to find a DVD drive attached to IDE controller 1 at location1.
#          I just use a quick and "dirty" way to get it.

$NewDVD = get-wmiobject -namespace root\virtualization Msvm_ResourceAllocationSettingData | `
                          where {($_.ResourceSubType -like "Microsoft Synthetic DVD Drive") -and ($_.InstanceID -like '*\1\1\*'" )}  

# Create a CD/DVD disk. To create a new disk you will search for the Default instance object and clone it.

$CD_Default = get-wmiobject -namespace root\virtualization Msvm_ResourceAllocationSettingData | `
                          where {($_.ResourceSubType -like "Microsoft Virtual CD/DVD Disk") -and ($_.InstanceID -like '*Default*'" )}  

$CDDisk = $CD_Default.psbase.Clone()
$CDDisk.Parent = $NewDVD.__PATH
$CDDisk.Connection = "c:\ISO\W2K3.ISO"

# Apply the changes
$VM_Service.AddVirtualSystemResources($VM.__PATH, $CDDisk.psbase.Gettext(1))

-------------------End of Script to Add a resource ----------------------------------------------

Done!

Until the next time ......

/Dung

 HyperV WMI PowerShell

 

Modifying Resources of a VM

Now that you know how to query WMI to get list of resources associated to a VM, let's discuss how you can modify a resource.

Modifying the location of VHD file

Let's say that my VM has a VHD file named C:\VMs\MyVM.VHD and I want to move the location of the file from C: to L: drive. After copying the VHD file to the new location, here is the script to change the location of the disk image file for the VM

-------------------Start of Script to modify a resource ------------------------------------------------

VM_Service = get-wmiobject -namespace root\virtualization Msvm_VirtualSystemManagementService
$VM = gwmi -namespace root\virtualization Msvm_ComputerSystem | where {$_.ElementName -like "My VM"}

## First you need to locate the active settings of a virtual machine
$VMSettingData = get-wmiobject -namespace root\virtualization Msvm_VirtualSystemSettingData -filter "SystemName = `'$($VM.Name)`'"

## Then find all the resources allocated to this VM.
## Here we are interested only on Msvm_ResourceAllocationSettingData instances.
$VResourceComponents = gwmi -namespace root\virtualization Msvm_VirtualSystemSettingDataComponent | `
                                       where {($_.GroupComponent -like $($VMSettingData.__PATH)) -and ($_.PartComponent -like `
                                      "*Msvm_ResourceAllocationSettingData*")} 

## IN this scenario, I'm interested only on the resources whose Subtype is "Microsoft Virtual Hard Disk "

foreach ($item in $VResourceComponents)

{

# Get a WMI instance from the path stored in the PartComponent Property

$VRes= [WMI]$item.PartComponent

if ( $VRes.ResourceSubType -eq "Microsoft Virtual Hard Disk")

       { $Res_VHD = $VRes }

}

if ($Res_VHD -ne $NULL)

         {

           $Res_VHD.Connection = $Res_VHD.Connection -replace "C:", "L:"

$VM_Service.ModifyVirtualSystemResources ($VM.__PATH, $Res_VHD.psbase.Gettext(1))

}

-------------------End of Script to modify a resource ------------------------------------------------

 

Enjoy!

/Dung

 HyperV WMI PowerShell

 

Today I will talk about finding resources of virtual machine.
A resource associated to a virtual machine includes virtual hard disk, NIC, DVD drive... and each resource is represented by an instance of a class Msvm_ResourceAllocationSettingData. This class has some interesting properties:

• Resource Type: a value indicating the generic type of resource such as: CPU, Memory, IDE Controller, Parallel SCSI HBA, FC SCSI HBA, iSCSI HBA, FCP Adapter, IB HCA, Ethernet Adapter, Other Network Adapter, I/O Slot, I/O Device, Floppy Drive, CD/DVD drive, Serial port, Parallel port, USB Controller, Graphics controller, Disk, Tape, Other storage device, Firewire Controller
• Resource SubType: a string that describes a specific implementation of the resource. For example, a disk drive in Hyper-V has a ResourceSubType of "Microsoft Disk Drive" which is MS implementation of the resource of type Disk.
• Connection: This is a link of the object to the "real" resource. For example, a hard disk drive of a VM that points to a VHD file has the Connection string set to the path of the VHD file.

 

Now that you understand how a resource is represented in Hyper-V, the next question is how those resources are attached to a specific Virtual Machine (VM). First all virtualization-specific settings of each VM is represented by an instance of the class Msvm_VirtualSystemSettingData.  The class describes a kind of "motherboard" of a VM. It has properties like BIOS, BaseBoardSerialNumber... Do note that a snapshot is also represented by an instance of the same class, it means that a snapshot is also viewed as a virtual machine of a specific type.

Once you get the Msvm_VirtualSystemSettingData, you can find all resources associated to a VM by querying the class Msvm_VirtualSystemSettingDataComponent. The query returns all associations between an instance of  Msvm_VirtualSystemSettingData and one or more instances of Msvm_ResourceAllocationSettingData.

This is how you can find resources that are allocated to a VM. You need to go through Msvm_VirtualSystemSettingData and then Msvm_VirtualSystemSettingDataComponet 

So let's put it in practice:

$VM_Service = get-wmiobject -namespace root\virtualization Msvm_VirtualSystemManagementService
$VM = gwmi -namespace root\virtualization Msvm_ComputerSystem | where {$_.ElementName -like "My VM"}

## First you need to locate the active settings of a virtual machine
$VMSettingData = get-wmiobject -namespace root\virtualization Msvm_VirtualSystemSettingData -filter "SystemName = `'$($VM.Name)`'"

## Then find all the resources allocated to this VM.
## Here we are interested only on Msvm_ResourceAllocationSettingData instances.
$VResourceComponents = gwmi -namespace root\virtualization Msvm_VirtualSystemSettingDataComponent | `
                                       where {($_.GroupComponent -like $($VMSettingData.__PATH)) -and ($_.PartComponent -like `
                                      "*Msvm_ResourceAllocationSettingData*")} 

## Now we have all resources associated to a VM, let's enumerate them

foreach ($item in $VResourceComponents)

{

# Get a WMI instance from the path stored in the PartComponent Property

$VRes= [WMI]$item.PartComponent

write-host "Type is $($VRes.ResourceType), SubType is $($VRes.ResourceSubType), Connection is $($VRes.Connection) "

}

Et Voilà!

/Dung

 HyperV WMI PowerShell