While writing config for App Service Plan, I came across the argument reserved in the terraform documentation
reserved - (Optional) Is this App Service Plan Reserved. Defaults to false.
I am not sure what this reserved argument would do if set to true, except that there is a note stating it must be set to true for Linux plan.
Couldn't find that property in Azure documentation either. Also I don't see that property while creating the plan through portal.
For your issue, just as the node shows you that it must be set to true for Linux plan. Here is a question in the Azure document for Linux service plan, it says if you want to create a Linux service plan, just set the reserved field to true. And there is also an issue in the Github, it shows this:
If you set "kind": "linux" but without setting "reserved": true, it deploys a Windows service plan with a Linux icon!
So just as the description shows in the REST API, the reserved field decides the service plan is Linux or other types.
