No matter how you like to participate in developer communities, Pulumi wants to meet you there. If you want to meet other Pulumi users to share use-cases and best practices, contribute code or documentation, see us at an event, or just tell a story about something cool you did with Pulumi, you are part of our community.

Pulumi Community

I think that user is referring to the machine that you're running Pulumi on as "a provisioner machine". Basically, you need to either run Pulumi from inside the VPC if it's impossible to interact with the RDS instance from outside. 

tl;dr The machine running Pulumi needs access to the RDS instance if it's going to interact with it

Oh, I undertstood is as that there is some kind of pre-made "resource" that would say create a lambda/ec2 inside the vpc to run my pulumi code..
But I guess I can do that manually then (or run pulumi from somwhere that has access to the vpc to begin with), thank you

No, we don't have a pre-made resource that will do this for you

We have examples and tutorials that will show you how to create ec2 instances and then you can install Pulumi on those, but nothing specific