hyperv-info-api

This is a small API project, meant to run as a Windows Service, that uses Powershell to manage Hyper-V VMs.

VM Data

This API uses the Notes field on the Hyper-V VM to store extra data about the VM that is used to set the AutomaticStartDelay for VMs. The data is stored in the following format:

{
    "startGroup": 0,
    "delayOffset": 0
}

Property	Type	Description	Default
startGroup	int	The one-based group used to calculate the start delay.	0
delayOffset	int	The offset within the group.	0

Delay Calculation

The AutomaticStartDelay is the delay, in seconds, before the host will start the VM. Based on the VM Data above, the following calculation is used:

delay = ((startGroup - 1) * groupDelay) + delayOffset

The above calculation is only run if the startGroup is greater than 1. The groupDelay can be specified in the POST to /vm/refreshdelay, but it defaults to 480 seconds.

Installing the Service

You can install this service using any of the methods described in Host ASP.NET Core in a Windows Service. The service will need to run as a user with Powershell access and rights to modify the VMs.

You will most likely have to create a new user and grant them service log on via local security policy. See Enable Service Logon for details.

Deployment Powershell

Once the service is installed, Deploy-ToMachine.ps1 can be used to stop the service on the target machine, build this library in debug, and copy the build to the machine. This is meant to be a template for your own deployments.

Authentication

This API is setup with optional JWT Bearer Token authentication. If you have an OAuth 2 service, you can configure authentication by setting the Identity values in the appSettings.json folder.

Identity Property	Description
AuthorityUrl	The url of the Token Authority
ApiName	This is the audience value required for the incoming call

At this time, only the audience is validated via the ApiName. Further validation, such as issuer and issuer signing key, can be added to the code if you need. How to Implement JWT Authentication in ASP.NET Core 6 will get you started.