how can i test this? hard to find documentation for building images

https://github.com/colemickens/nixcfg/tree/master/machines/azure

That's what I'm using currently to build images. I think something like ./upload-image.sh ./image-azplex.nix will build+upload an image an output the Azure Image ID.

Then ./boot-vm.sh should create a running VM booted from that image.

from a pm with @colemickens (hopefully you dont mind me posting it)

not sure if this is right, but:

[nix-shell:/home/jon/.cache/nixpkgs-review/pr-78827-1]$ nix-build -E "(import ./nixpkgs/nixos/lib/eval-config.nix { modules = [ ./nixpkgs/nixos/modules/virtualisation/azure-image.nix ({...}: { config.virtualisation.azureImage.diskSize = 4096; }) ]; }).config.system.build.azureImage"
...
WARNING: Image format was not specified for 'nixos.raw' and probing guessed raw.
         Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
         Specify the 'raw' format explicitly to remove the restrictions.
qemu-system-x86_64: CPU model 'host' requires KVM
builder for '/nix/store/4xd7jnanlllr2jl0bmsxga3nmwck23qs-azure-image.drv' failed with exit code 1
error: build of '/nix/store/4xd7jnanlllr2jl0bmsxga3nmwck23qs-azure-image.drv' failed

looks like I had CPU virtualization turned off on my BIOS.....

Thanks for testing @jonringer. Seems like you're maybe unblocked, I had meant to reply earlier...

Indeed, @dali99 shared the best instructions I have right now; that's what I use anyway. Once this change is in, I was going to extract another piece from my nixcfg and replace what is in nixos/scripts/maintainers/azure.

For those subscribed, I've updated this significantly. To summarize, I'll just copy the new PR body text. It now includes:

• add a diskSize option
• enable boot.growPartition so that / is expanded when it boots in Azure
• add a pair of scripts that make it easy to see how to:
  1. build a custom image and upload it as a disk, then create a re-usable image from it
  2. boot a VM from the image

And the demo! https://asciinema.org/a/euXb9dIeUybE3VkstLWLbvhmp

We may want to update this page as well, but that can be done outside of this PR https://nixos.org/nixos/download.html#microsoft-azure

I left the fixes as separate commits for reviewers. LMK what you think and I can squash.

do you have issues with azcopy? Yesterday it was murdering my network, but overall using very little bandwidth

I run from my local network where I have symmetric gigabit, or from Azure, so I tend not to notice. I've only ever monitored it from an "eye ball the status bar / percentage" standpoint and it's done what I've expected.

How were you observing this? Was it starving other things? Were you monitoring its network usage?

I was trying to join a conference call, and I couldn't. And my network usage utility was showing me <100KB/s , when azcopy was showing 1MB/s+.

Hm, yeah, I'm not sure, I don't think I've seen that. It's possible that az can upload directly to the disk blob now, a bit confusing/silly that I had to use azcopy for it in the first place.

I don't see any options to use the disk command for upload, however, you can upload to blob then use blob url to create disk

        az disk create -g MyResourceGroup -n MyDisk --source
        https://vhd1234.blob.core.windows.net/vhds/osdisk1234.vhd

I spent considerable time figuring out how to avoid Azure storage accounts so, I'm unlikely to write any code that deals with storage accounts unless there's literally no other way.

Do you mind if I write it? then we can also remove the azure-storage-azcopy dependency

Here's my take. I've written the storage account management code many times and worked relatively hard to figure out the undocumented-yet-publicly-available APIs in order to remove that goop from this version of this PR - storage accounts are slow, take multiple steps to create, have annoying, asinine naming requirements, and, in this scenario, are only necessary because ... well... it's Azure.

I know this works and would prefer to merge as-is. If you want to revise it and remove azcopy, and you can make it so I can safely just look away during the storage account part (maybe even clean it up), then that seems reasonable. But I'm pretty resolved that the right fix is Azure-CLI fixing SAS Blob uploads... Azure/azure-cli#10192

Here's my take. I've written the storage account management code many times and worked relatively hard to figure out the undocumented-yet-publicly-available APIs in order to remove that goop from this version of this PR - storage accounts are slow, take multiple steps to create, have annoying, asinine naming requirements, and, in this scenario, are only necessary because ... well... it's Azure.

Agreed

I know this works and would prefer to merge as-is. If you want to revise it and remove azcopy, and you can make it so I can safely just look away during the storage account part (maybe even clean it up), then that seems reasonable. But I'm pretty resolved that the right fix is Azure-CLI fixing SAS Blob uploads... Azure/azure-cli#10192

That's fair, I'll open a new PR with a azcopyless version

Thanks Jon. I'll update docs now.