A simple beginner question: what happens if you manually created some resources in Azure and you use these resources in a stack? Will the resources be (re)created? Of only the new ones?

depends on how you use them: * if you just want to reference existing resources, generally there's a

<resource>.get

function that returns a reference to the existing resource. You can use this elsewhere in your stack and it won't be modified. * if you want to 'adopt'/'import' existing resources, you define the resource as if it were brand new, and add some additional information to show pulumi how to reference it. this kind of use will result in pulumi making changes to the resource. more info here: https://www.pulumi.com/blog/adopting-existing-cloud-resources-into-pulumi/