Created for the following post: https://www.wporter.org/getting-started-with-cloud-init-on-hyper-v
This will demonstrate using PowerShell to generate a basic Cloud-init config and stand up an AlmaLinux VM from the AlmaLinux Generic Cloud image on a Server 2025 or Windows 11 24H2 Hyper-V host. What follows is an excerpt from the linked post.
Get a VHDX cloud-init image
To convert an image:
(irm https://cloudbase.it/downloads/qemu-img-win-x64-2_3_0.zip -outfile qemu-img.zip); expand-archive .\qemu-img.zip
.\qemu-img\qemu-img.exe convert -O vhdx .\AlmaLinux-8-GenericCloud-latest.x86_64.qcow2 .\AlmaLinux-8-GenericCloud-latest.x86_64.vhdxGet oscdimg
Import-Module .\cloudinit-vm.ps1
$bind = @{
VMName = 'bind.lab.wporter.org'
VMSwitchName = 'vlab0-natswitch'
OriginalVHDXPath = '.\al9gc.vhdx'
Username = 'liam'
PublicKey = 'ssh-ed25519 Zn'
Force = $true
HashedPassword = ('foobar' | ConvertTo-SecureString -AsPlainText -Force)
}
CloudInit-VM @bindCreating a hashed PW you can pass through:
liam@liam-z790-0:~$ salt=$(openssl rand -base64 16)
liam@liam-z790-0:~$ hashed_string=$(openssl passwd -6 -salt "$salt" foobar)
liam@liam-z790-0:~$ echo "$hashed_string"
$6$7oxzBYUGVIiTl7mK$u/VhUPQwTFi2TtwU7iKFbdIaWfKWzrYPxxmVxJI07Ulz2Wy4XHE6qS0zwsTZ9lYX2JK/TQLRtb77j2urZci.e/- qemu-img (only if you need to convert GenericCloud images to VHDXes - Azure images MIGHT work out of the box)
- genisoimage, mkisofs, xorriso, or oscdimg
You will also need a GenericCloud image of some kind to use this.
qemu-img alone can be downloaded from Cloudbase Solutions (the company that supports the "cloud-init for Windows" tool cloudbase-init): https://cloudbase.it/qemu-img-windows/.
Get it with PowerShell:
(irm https://cloudbase.it/downloads/qemu-img-win-x64-2_3_0.zip -outfile qemu-img.zip); expand-archive .\qemu-img.zipThe archive will look something like this:
PS C:\Users\liam\projects\cloud-init-a9> gci qemu-img
Directory: C:\Users\liam\projects\cloud-init-a9\qemu-img
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a--- 9/18/2013 1:35 PM 86528 libgcc_s_sjlj-1.dll
-a--- 3/30/2015 3:09 PM 2584872 libglib-2.0-0.dll
-a--- 3/30/2015 3:10 PM 79707 libgthread-2.0-0.dll
-a--- 3/30/2015 3:38 AM 1475928 libiconv-2.dll
-a--- 3/30/2015 1:59 PM 464017 libintl-8.dll
-a--- 9/18/2013 1:35 PM 18944 libssp-0.dll
-a--- 6/16/2015 9:37 PM 5615492 qemu-img.exeMore complete QEMU binaries for Windows (include qemu-img) can be found at: https://qemu.weilnetz.de/w64/.
oscdimg is a part of the Windows Assessment and Deployment Kit, which can be installed with the winget package manager, if you have that installed (24H2+, incl. Server 2025 have Winget working by default).
Note that installing the ADK this way will not prompt you to select which components to install - and, by default, the ADK has a 2gb footprint, which is a bit much for just a tool to build ISOs.
winget install Microsoft.WindowsADKAlternatively, you can download and run the ADK installer directly from Microsoft. If you do it this way, you can select only the "Deployment Tools" feature and save some disk space, or download and run the oscdimg installer alone.
(irm https://go.microsoft.com/fwlink/?linkid=2196127 -method GET -outfile adksetup.exe) |
.\adksetup.exeIf you install the Deployment Tools, oscdimg will, by default, be at: C:\Program Files (x86)\Windows Kits\10\Assessment and Deployment Kit\Deployment Tools\amd64\Oscdimg\oscdimg.exe.
If you download the Deployment Tools, you won't be prompted to select which features you want, but can then navigate to the downloaded directory and run the oscdimg installer Oscdimg (DesktopEditions)-x86_en-us.msi.
If you downloaded the ADK to your Downloads directory, the path to the installer(s) including that for oscdimg would be ~\Downloads\ADK\Installers.
I have an archive containing oscdimg.msi and its required .cab files. This could be a useful way to quickly install just the component you want.
For reference, those files are:
Mode LastWriteTime Length Name
---- ------------- ------ ----
-a---- 1/20/2025 8:15 PM 81130 52be7e8e9164388a9e6c24d01f6f1625.cab
-a---- 1/20/2025 8:15 PM 80196 5d984200acbde182fd99cbfbe9bad133.cab
-a---- 1/20/2025 8:15 PM 81299 9d2b092478d6cca70d5ac957368c00ba.cab
-a---- 1/20/2025 8:16 PM 84314 bbf55224a0290f00676ddc410f004498.cab
-a---- 1/19/2025 10:22 PM 417792 Oscdimg (DesktopEditions)-x86_en-us.msiFinally, here's a link to the Oscdimg help page at (on?) MS Learn.
I typically use WSL on my workstation, so I figured I'd include this as well. It's a little easier to get qemu-img this way, but you might not want/be able to go the WSL route on a locked-down work laptop or Windows build box.
You can install both genisoimage and qemu-img on Debian 12 from the standard repositories:
# apt install genisoimage qemu-imgOn Enterprise Linux & friends (I like to use Alma), you'll have to install EPEL first.
# dnf install epel-release
# dnf install genisoimage qemu-imgThis is one command (qemu-img convert -O vhdx), once you've downloaded qemu-img somewhere.
.\qemu-img\qemu-img.exe convert -O vhdx GenericCloud.qcow2 .GenericCloud.vhdxOnce you've got a VHDX, you can come up with some parameters:
$ManicPgSQLParams = @{
VMName = 'manictime-pgsql'
VMSwitchName = 'ext-untagged'
OriginalVHDXPath = 'D:\VHDX\AlmaLinux-9-GenericCloud-122024.vhdx'
Username = 'liam'
PublicKey = 'ssh-ed25519 ssh key here'
Force = $true
}Import the cloudinit-vm.ps1 file (containing one function) as a module, then run the function, like so:
CloudInit-VM @ManicPgSQLParamsHere's the full list of parameters that may be set in its current state:
param (
[string]$VMName = 'manictime-pgsql',
[string]$VMSwitchName = 'ext-untagged',
[string]$OriginalVHDXPath = 'D:\VHDX\AlmaLinux-9-GenericCloud-122024.vhdx',
[string]$CloudInitMetadataPath = 'C:\tmp\cloud-init',
[string]$CloudInitMetadataOutPath = 'C:\tmp\cloud-init.iso',
[string]$Username = 'cloud-user',
[string]$PublicKey,
[securestring]$HashedPassword = 'aabbccddeeff',
[int]$vCPUs = 8,
[long]$Memory = 8GB,
[bool]$Force = $false
)Self explanatory
The Hyper-V vSwitch you would like to attach the VM to.
The Cloud-init-ready image you would like to copy to create your new VM.
Path to the directory that will be used for metadata.
Path to the ISO image that will be created from said metadata.
The user that will be created in your VM with Cloud-init.
The created user's SSH public key
If you'd like to use a password, you could uncomment this and the other relevant lines in the script. To create a hashed password, use the mkpasswd utility provided by the whois package (Debian 12) or mkpasswd package (AlmaLinux 9 appstream). Alternatively, you can use OpenSSL directly:
liam@liam-z790-0:~$ salt=$(openssl rand -base64 16)
liam@liam-z790-0:~$ hashed_string=$(openssl passwd -6 -salt "$salt" foobar)
liam@liam-z790-0:~$ echo "$hashed_string"
$6$7oxzBYUGVIiTl7mK$u/VhUPQwTFi2TtwU7iKFbdIaWfKWzrYPxxmVxJI07Ulz2Wy4XHE6qS0zwsTZ9lYX2JK/TQLRtb77j2urZci.e/You can probably use OpenSSL for Windows. There is no native way to do this, as far as I'm aware, because the SHA-512-CRYPT algorithm is not implemented by .NET cryptography libraries.
The number of threads to assign to the VM
The amount of memory, in bytes, to assign to the VM
Optional flag to overwrite existing files instead of failing
Anyway. Yeah. This is an example I chucked together for a post, so don't judge me too harshly on the lack of code quality. I'd recommend reading the blog post (again, that's at https://www.wporter.org/getting-started-with-cloud-init-on-hyper-v) for the full deetz. Happy VM-ing-ing!