Chapter 3. Managing Your Hyper-V Virtual Machines

In this chapter, we will continue to explore the PowerShell cmdlets available in the Hyper-V PowerShell module to manage virtual machine infrastructure components. This chapter has been subdivided into smaller sections and we will be covering the following topics:

· Managing virtual switches and virtual network adapters in virtual machines

· Managing virtual machine migrations

· Managing virtual machine imports, exports, and snapshots

· Managing virtual machine backups with Hyper-V Replica

· Managing virtual machine connect

With Hyper-V you can configure a virtual machine to use a dynamic or a static MAC address for any given network adapter. The default option is to use a dynamic MAC address – which means that Hyper-V will generate an initial MAC address for the network adapter, and it will regenerate the MAC address if it believes it is necessary. In Hyper-V on the mainline Enterprise branch (Build 1803 17134.345), I've only ever seen the Default Switch assign a Class B address in the 172.X.X.X range, and the last three octets seem variable. Although, when I create a new External Switch (haven't tried the other types), it is assigned a Class C address in the 192.X.X.X range.

We will start by taking a deep dive into cmdlets, which can help us manage the virtual machine switches and network adapters; this will help us to understand the various ways to automate network configuration for virtual machines. Next, we will explore the cmdlets that allow a Hyper-V admin to manage virtual machine migrations across hosts and clusters. After that, we will explore cmdlets that allow us to export, import, and use snapshot-based technology on virtual machines, which aids in the quick testing of installed applications on virtual machines and also serves as a backup mechanism. Next, we will also explore the cmdlets related to Hyper-V Replica—a new disaster recovery technology—which allows an administrator to back up a virtual machine to a secondary site and maintain its high availability when the primary data center goes offline. Lastly, we will explore virtual machine connect—a new feature that uses the VMBus as a connection path and allows the administrator to connect to virtual machines without using a network connection.

Managing virtual switches and virtual network adapters

The Hyper-V PowerShell module comes with a set of cmdlets, which can be used to manage the virtual machine network adapters and virtual switches. Virtual machine networks and switches form the core networking component of virtual machines. Virtual switch is a software-based network switch that helps in connecting virtual machines to virtual and physical networks. They can be of three types: external, internal, and private. Once the virtual switches are created, the virtual network adapters created for a virtual machine can be tagged to these virtual switches, allowing the virtual machine to connect to both physical and virtual networks. The virtual network adapters assigned to a virtual machine require it to have the required drivers provided by integration services to be installed on it.

Open a PowerShell prompt, and type the cmdlets shown in the following screenshot to get a list of all the cmdlets that are available to manage the virtual network and virtual switches:

Let's explore these cmdlets and look at their real-world applications.

Managing a virtual machine's migration networks

Let's look at how to add an IPv4 address range as a possible live migration network on the local Hyper-V host by using a subnet mask:

1. Open a PowerShell prompt and type the command shown in the following screenshot:

2. Once we execute the cmdlet shown in the preceding screenshot, we will be able to see that the network has been added as a live migration network in the Hyper-V manager:

This can also be attained by executing the Get-VMMigrationNetwork cmdlet:

3. Similarly, one can use the Remove-VMMigrationNetwork cmdlet to remove the virtual machine migration network that has been assigned to the Hyper-V host.

4. The command shown in the following screenshot removes all the networks starting with the address, 192.168, for the migration:

5. To get a list of all the virtual machine's live migration networks on the system, type the cmdlet shown in the following screenshot:

Next, we will look at an example, which adds an Access Control List (ACL) to allow the virtual machine, testvm, to send and receive from traffic on the IP subnet, 192.168.11.0/24. Executing this cmdlet creates an ACL that can be applied to specific traffic that is passing through a virtual machine network.

6. You can also use the Get-NetworkadapterAcl cmdlet to verify the changes that were made:

Configuring virtual machine network adapters with a virtual switch

Now, we will look at the cmdlets that can be used to manage virtual machine migration networks, and later, we will look at some examples on how you can use the Connect and Disconnect network adapter cmdlets to assign a network adapter to a virtual switch.

The InternetAccess cmdlet will connect a virtual network adapter named Internet present in virtual machines Test1 and Test2 to a virtual switch named. For the command shown in the following screenshot to work, the prerequisite is that there should be a network adapter named Internet present on both these virtual machines:

Another use case would be to connect all the virtual machine network adapters present on a virtual machine to a virtual switch. The next example shows how this can be done by using the PowerShell pipeline. The cmdlet shown in the following screenshot illustrates how you can connect all the virtual network adapters in a virtual machine, Test1, to a virtual switch, InternetAccess:

Similarly, let's look at another use case to disconnect all the virtual machine networks from a virtual switch that is available on all the virtual machines hosted on the Hyper-V host. The cmdlet shown in the following screenshot disconnects all the virtual network adapters whose switch name is InternetAccess in all the virtual machines on the local Hyper-V server:

Next, we will take a look at an easy way to extract all the virtual networks attached to the virtual machine. Executing the cmdlet shown in the following screenshot gives more details about the virtual switch MAC addresses and also the IP addresses:

The cmdlet shown in the preceding screenshot when run with the –All switch gives details on all the virtual network adapters on both the virtual machines and the management switches:

Configuring virtual machine network failover settings

Hyper-V allows an administrator to configure failover capabilities for a virtual machine's network adapter IP address after the Hyper-V Replica recovers the virtual machine at the disaster recovery site; these failover details can be extracted and set up by using the next cmdlet. The cmdlet shown in the following screenshot configures a failover IPv4 address for the virtual network adapter, NetworkAdapter01, on a virtual machine, VM01:

The cmdlet shown in the following screenshot clears the current failover IPv4 settings on the virtual network adapter, NetworkAdapter01, for a virtual machine, VM01:

The cmdlet shown in the following screenshot clears the current failover IPv6 settings on a virtual network adapter NetworkAdapter01 for a virtual machine, VM01:

The cmdlet shown in the following screenshot obtains the failover IP address configuration of all the virtual network adapters attached to a virtual machine named VM01:

Adding, removing, and renaming virtual machine network adapters

Adding a new virtual machine network adapter to a virtual machine is relatively simple by using the Add-VMNetworkAdapter cmdlet. The cmdlet shown in the following screenshot adds a network adapter, New Network, to a virtual machine named SCOM2012R2_1:

You can also remove the virtual machine network adapter attached to a virtual machine by using the Remove-VMNetworkAdapter cmdlet. The example shown in the following screenshot removes the network adapter, Network Adapter, from a virtual machine namedSCOM2012R2_1:

Similarly, the example shown in the following screenshot renames all the virtual network adapters of a virtual machine, SCOM2012R2, to NewNetwork:

Configuring a virtual machine's network adapter VLANs

Hyper-V PowerShell cmdlets also allow the administrator to assign a VLAN to a virtual machine network. The cmdlet shown in the following screenshot sets the virtual network adapter(s) in the virtual machine, scom2012r2_1, to the Access mode; also, the traffic sent by this virtual machine is tagged with the VLAN ID, 2:

The Get-VMNetwork

Microsoft Hyper-v Address Range