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

Edit: Resolved. We did indeed have to wrap the whole userData generation process inside an apply for aws.ec2.LaunchTemplate to pass pulumi.Output<string> vars into it:
```    imageId: "ami-0427090fd1714168b",
    instanceType: "m5.xlarge",
    keyName: "Lovelace-EC2-KP",
    updateDefaultVersion: true,
    userData: masterApiKey.apply(apiKey => {
        return Buffer.from(getUserData(deploymentMask, apiKey)).toString('base64')
    }),```