title: What is the reserved argument in azure app service plan terraform config
body: <p>While writing config for App Service Plan, I came across the argument <em>reserved</em> in the <a href="https://www.terraform.io/docs/providers/azurerm/r/app_service_plan.html" rel="noreferrer">terraform documentation</a></p>
  
  <blockquote>
    <p>reserved - (Optional) Is this App Service Plan Reserved. Defaults to false.</p>
  </blockquote>
  
  <p>I am not sure what this <em>reserved</em> argument would do if set to true, except that there is a note stating it must be set to true for Linux plan.</p>
  
  <p>Couldn't find that property in <a href="https://docs.microsoft.com/en-us/cli/azure/appservice/plan?view=azure-cli-latest" rel="noreferrer">Azure documentation</a> either. Also I don't see that property while creating the plan through portal.</p>