How can I build a Linux VM that I can use to test Rest API calls in a lab? I work in Enterprise CloudOps Support and the products we support use Rest API for notifications. Frequently we get requests to help troubleshoot solutions like Pager Duty, PagerTree, ServiceNow, etc. Obviously I can't and won't signup for trials of these products, nor do I need to know them. However, I do need to know how Rest API works and how to set it up. I've been researching it and so far all I've found is this MS DevOps write-up: https://microsoft.github.io/PartsUnlimitedMRP/pandp/200.1x-PandP-LocustTest.html

However, as of yet I can't seem to make sense of some of the steps. I thought there must be a better way, so here I am. Ultimately what I'm after is a VM that I can build in a lab and use for testing Rest API calls that relay notifications, alerts, etc.
You can test basically any rest api call from postman, a free app that runs perfectly well in windows or Linux (or Mac I’m sure).  You don’t need anything special.

If you want to use Linux specific tools, you can sign up for AWS free tier and make a Linux box in minutes following any of their tutorials (it will be free for 1 year).

You can also use docker on your computer (including on windows).  Docker will be suitable for running most non GUI based or web GUI based Linux apps.  I see a locust image here for example - https://docs.locust.io/en/stable/running-locust-docker.html.