How to create multiple VMs in Hyper-v

WonderWoman · Mar 14, 2024

Hello,

I will be starting to create multiple VMs that will all be running Win11 Pro in Hyper-v on my Win11 Pro computer. I know that it is easy to just create them one by one but I want to learn some more advanced methods to enhance my skills/knowledge. I am aware that there's a method to create multiple VMs at once but I have never done it before. One thing to note about my skills/knowledge is that I am EXTREMELY WEAK on everything that gets done either through a command prompt or Powershell, so to anyone helping, I appreciate the help but I will need more than the ordinary hand holding so-to-speak.

I did see some post on here referencing "copy any vhdx and attach to new vm" which sounds like it might be what I need to do. Can I get some more details on that process along with any articles to read or tutorials to watch?

pparks1 · Mar 14, 2024

Here is a powershell example for creating a vm.

New-VM -Name "Kali Linux" -MemoryStartupBytes 4GB -Path "D:\VM\Kali Linux" -NewVHDPath "D:\VM\Kali Linux\Kali Linux.vhdx" -NewVHDSizeBytes 40GB -Generation 2 -SwitchName "Ethernet"

Bree · Mar 14, 2024

WonderWoman said:
I will be starting to create multiple VMs that will all be running Win11 Pro in Hyper-v on my Win11 Pro computer. I know that it is easy to just create them one by one but I want to learn some more advanced methods to enhance my skills/knowledge.

This sounds like an ideal case for using differencing disks. You create your .vhdx with a clean install of W11 Pro installed just the once, then leave it alone and untouched. For each VM you create its own Child disk, with your standard install of W11 Pro on the original disk as the Parent. The Parent could be at the point when it's ready to do the OOBE setup, that way each VM would boot up to the initial 'setup' screen and you could configure each one individually. All subsequent changes to each VM are stored in its Child disk, the Parent remains unaltered. Tutorial here:

Hyper-V - Use Differencing Disks

How to Use Differencing Disks in Hyper-V

www.tenforums.com

Microsoft documentation here:

Microsoft Docs said:
Using multiple differencing disks with one parent disk
You can associate more than one differencing disk to one parent, which means that virtual machines can share one parent disk but have their own differencing disk. This way of using differencing disks can be useful in a variety of scenarios. For example, a test engineer or call center technician could have a dozen or more virtual machines with different configurations, such as allocated memory or type of networking, with different software updates, and different installed applications. The virtual machines could share a parent disk that contains the operating system, and each virtual machine could have its own differencing disk to store the configuration that differs from the parent.

Using differencing disks

learn.microsoft.com

pparks1 · Mar 14, 2024

Differencing disks are great...but I find that I don't often need to run multiple versions of the same OS.

Bree · Mar 14, 2024

pparks1 said:
Differencing disks are great...but I find that I don't often need to run multiple versions of the same OS.

Neither do I. But that is exactly what @WonderWoman wants to do - so it should be just what is needed here.

cereberus · Mar 15, 2024

We need to understand what OP @WonderWoman wants to do.

1 - why do you want multiple vms

2 - are you wanting to run more than 1 vm at q time.

3 - each vm needs a licence. Are you sure this is what you want.

3. You would need a powerful pc to run say 3 or more vms - even twio could be a stretch. Using SSD for vms is pretty much essential.

4. Rather multiple vms, you could have a single vm, and create multiple vhdx files each with an installation of Pro, and create boot entries so you get a menu to select which OS to use.

5 - Differencing disks may help save space but it sort of depends on what you are trying to do. They can be complicated to update and manage.

6. It would definitely be easier to set up pne vhdx file and copy it several times.

7. Would you need access to external drives on the host?

8. Would you want to network between the vms?

We need some detailed understanding of what you are trying to achieve, so we can advise best approach.

Even then, it is quite a learning curve, and I suggest you peruse the Hyper-V tutorials on the sister tenforums site.

In the end, baby steps is the way to learn.

jimbo45 · Mar 15, 2024

Hi there
I find unless you really want to run concurrent VM's then the best way is to create several vhdx files on the same "Virtual disk" and then at boot you get a choice of which Windows system to boot into -- and it's the SAME VM - even though multiple Windows systems.

The Virtual Disk Geometry (not physical disk) needs to be -- Main EFI partition, Msr, vhdx1, vhdx2, vhdx3 etc.

the vhdx disks should be formatted as plain ntfs disks.

To install the VM's you need from Hyper-V to boot the Windows install media for the system you want to create and then do the install via Dism /Apply-Image. To do that simply from the install choose "repair system -->command mode and use diskpart to mount the EFI partition, and the vhdx file for the target of the install.

Of course if you have wildly different hardware to test on VM's then you'd need to make separate VM's. One advantage of using a single VM which contains several different vhdx windows systems is that you don't have potential problems of Windows activation going bonkers because the uuid of the VM is different - and often Windows activation flags that as changed hardware.

Tip though if doing it this way keep your Windows installs small - data such as multi-media, office stuff etc in any case should be on separate disks / partitions to the main OS.

Also a tip -- if doing multiple vhdx installs to the same VM endure the boot loader goes to the primary efi file to avoid a 2nd boot after you''ve selected your OSso the boot menu will boot straight into the OS without another reboot.

Cheers
jimbo

WonderWoman · Mar 16, 2024

pparks1 said:
Here is a powershell example for creating a vm.

New-VM -Name "Kali Linux" -MemoryStartupBytes 4GB -Path "D:\VM\Kali Linux" -NewVHDPath "D:\VM\Kali Linux\Kali Linux.vhdx" -NewVHDSizeBytes 40GB -Generation 2 -SwitchName "Ethernet"

Uhhh.....did I mention that they will all be running Win11 Pro and that I suck at all forms of command line everything type of scripting?

WonderWoman · Mar 16, 2024

jimbo45 said:
Hi there
I find unless you really want to run concurrent VM's then the best way is to create several vhdx files on the same "Virtual disk" and then at boot you get a choice of which Windows system to boot into -- and it's the SAME VM - even though multiple Windows systems.

The Virtual Disk Geometry (not physical disk) needs to be -- Main EFI partition, Msr, vhdx1, vhdx2, vhdx3 etc.

the vhdx disks should be formatted as plain ntfs disks.

To install the VM's you need from Hyper-V to boot the Windows install media for the system you want to create and then do the install via Dism /Apply-Image. To do that simply from the install choose "repair system -->command mode and use diskpart to mount the EFI partition, and the vhdx file for the target of the install.

Of course if you have wildly different hardware to test on VM's then you'd need to make separate VM's. One advantage of using a single VM which contains several different vhdx windows systems is that you don't have potential problems of Windows activation going bonkers because the uuid of the VM is different - and often Windows activation flags that as changed hardware.

Tip though if doing it this way keep your Windows installs small - data such as multi-media, office stuff etc in any case should be on separate disks / partitions to the main OS.

Also a tip -- if doing multiple vhdx installs to the same VM endure the boot loader goes to the primary efi file to avoid a 2nd boot after you''ve selected your OSso the boot menu will boot straight into the OS without another reboot.

Cheers
jimbo

Hiya,

Thanks for the reply. First question I have is going to sound really really stupid.....but without quoting the comment is there a method to simply reply on the forum? I find that many times it is not necessary to quote, only a reply comment is needed (like now).

Second, many times I would be running these VMs simultaneously on the same computer. Would that make any difference in what ever process I would need to do in order to create multiple VMs that were nothing more than copies of the original?

Third, they would all be run as individual computers from one physical desktop computer which is running Win11 Pro. It would be my second computer that I just built.

Fourth, much of what you described with the commands went right over my head a bit. Years ago when I first started on computers I metaphorically shot myself in my own foot with how I started. I never learned command line anything. I started on an Apple (at the time it was a Performa 400/LCII running System 7) and then I migrated right over to Win 3.1.1 so I was always on folders and such with what I call "ya want it, ya see it, ya click it" functionality. Cut to all of these years later and now at age 57 I am realizing how much I hurt myself with that. Having to learn all that at this age while also having ADD is HARD (and it sux). I can learn it though and will learn it though, but never to the core of the entire "subject theory" like out of a book for anything.

WonderWoman · Mar 16, 2024

cereberus said:
We need to understand what OP @WonderWoman wants to do.

1 - why do you want multiple vms It is a personal project involving attending and sometimes recording conference calls. I already have the recording from a VM part down and I am doing it from another physical machine, so I don't need help with that part of the project.

2 - are you wanting to run more than 1 vm at q time. Yes, most times they will be running simultaneously from the same physical computer, which is the second computer listed in my profile, a desktop computer I just built that is running Win11 Pro.

3 - each vm needs a licence. Are you sure this is what you want. I will not be activating Windows. I don't need to. I only need basic functionality.

3. You would need a powerful pc to run say 3 or more vms - even twio could be a stretch. Using SSD for vms is pretty much essential. I will be running them from my brand new desktop PC that I just built. The configs are listed in my profile on here as my second system.

4. Rather multiple vms, you could have a single vm, and create multiple vhdx files each with an installation of Pro, and create boot entries so you get a menu to select which OS to use. That suggestion won't work for what I will be doing. They must be separate individual VMs.

5 - Differencing disks may help save space but it sort of depends on what you are trying to do. They can be complicated to update and manage. What are differencing disks?

6. It would definitely be easier to set up pne vhdx file and copy it several times. I think that sounds like what I need to learn how to do for this project.

7. Would you need access to external drives on the host? I have a QNAP NAS enclosure in my apartment, so, yes, I would definitely want that option available. I already know how to do the "enhanced" sessions of VMs when connecting to them.

8. Would you want to network between the vms? Possibly, I would like to keep that option open.

We need some detailed understanding of what you are trying to achieve, so we can advise best approach. I would be needing simple functionality for the most part, absolutely nothing advanced. Mostly just for attending conference calls and participating and sometimes recording. Additionally for accessing the internet.

Even then, it is quite a learning curve, and I suggest you peruse the Hyper-V tutorials on the sister tenforums site. I was not aware that there was a tenforums version of this....I would love to get a link to those tutorials if possible please....I am however, also on techsupportforum.com

In the end, baby steps is the way to learn.

I have already been working with just a basic few VMs on my MSI Katana GF66 laptop (that is the first computer listed in my profile) but now that my desktop build is complete I am looking to step up my skills a bit. I have been trying to read up on this in some books I have but they are not discussing the topic of creating multiple VMs in a sort of a "Xeroxing" or duplicating method. They also haven't referenced (so far) anything about "differencing disks" either but I am still researching in the multiple books I have. I also must say that the books even to purchase new are not updated or current. It seems that authors have not bothered to write anything new on this in at least 5+ years.

Bree · Mar 16, 2024

WonderWoman said:
5 - Differencing disks may help save space but it sort of depends on what you are trying to do. They can be complicated to update and manage.
What are differencing disks?

See my post #3, and in particular the link I gave there to a Ten Forums tutorial that explains differencing disks in detail.

pseymour · Mar 16, 2024

WonderWoman said:
I have been trying to read up on this in some books I have but they are not discussing the topic of creating multiple VMs in a sort of a "Xeroxing" or duplicating method. They also haven't referenced (so far) anything about "differencing disks" either but I am still researching in the multiple books I have.

Your books may refer to them as "linked clones," since that is the term used in VMware environments, and VMware is the dominant player in this field. You basically only hear "differencing disk" when talking about Hyper-V.

cereberus · Mar 16, 2024

Differencing disks are only of any use when you have one vm running the parent disk with one or multiple child disks. You can only run instance of windows at a time.

They are of no use for @WonderWoman''s case. She has made it clear she may be running several vms in parallel.

Then her solution is really simple - create a vhdx file for first vm, and if she wishes then simply copy vhdx file (copy, paste from file explorer) and then attach each copy to a new vm.

pparks1 · Mar 17, 2024

WonderWoman said:
Uhhh.....did I mention that they will all be running Win11 Pro and that I suck at all forms of command line everything type of scripting?

It was just an example for syntax. Obviously will have to change a few things, but with a little trial and error I bet you can get it working.