Is it not possible to have multiple projects when using the aws backend? When I try to create a second project with a stack named the same as a stack in my first project, I get an error about the stack already existing.

That’s right. See also https://github.com/pulumi/pulumi/issues/2522 and https://github.com/pulumi/pulumi/issues/2814.

@white-balloon-205 thanks for those links. I think I'm a little confused now. If I log into a different backend (even if it is within the same s3 bucket, just a different folder structure within it) then it doesn't sound like I can do a stack reference to a stack in another project, right? How can I setup the aws backend to have multiple projects with the ability to do stack references across projects?

I believe you have to log into the same backend across projects, and then use stack names that are unique across all projects - for example following a naming pattern of

<project name>-<stackname>

.

Hmm.. I see. I wish it worked a little more like the Pulumi SAAS offering. I can get this to work though. I'm already separating my environments into different git repositories, so I was already going to have 1 stack per pulumi project, so this should be ok to do (1 project, multiple stacks)

Right - the goal is that those two issues will be addressed so that this is easier.