How does Jetty deployment on Azure App Service work?

So, Azure API Apps are a PAAS, not IAAS service. You can access the PaaS platform by coming to yoursite.scm.azurewebsites.net, where you can browse the file system in CMD or Powershell, and you can see the running processes. This may feel like you are on a single VM, but you are not. The data you see here is replicated down into your API App instances. You can control how many instances you have through scaling your API App.

I have commonly seen your issue with deploying, then ROOT being empty(working internally to see this fixed...). The best method that works every time for me, is to stop your API App, manually UNZIP your ROOT.war. Move the files into /ROOT/, then to start your API App.

You can simply place ROOT.war, and let the system unpack it when you turn it back on, but this can sometimes lead to that empty ROOT directory, then requiring another restart.

All of this has me moving to Spring-Boot instead. No unpacking required. Simply configure your web.config and drop the jar file.

https://docs.microsoft.com/en-us/azure/app-service-web/web-sites-java-custom-upload#springboot

I had the same problem. The solution is to call the endpoint after de deploy.

1. Stop the Azure App Service.
2. Deploy the ROOT.war artifact in the /webapps folder.
3. Start the Azure App Service.
4. Call the URL of the App Service once.

The four-step is very important and start the process that you mentioned before (the automagically deploy).

I lost a lot of time figuring out what was the problem.