AWS Resources Using AssumeRole

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This example shows how to use the AssumeRole functionality of the AWS provider to create resources in the security context of an IAM Role assumed by the IAM User running the Pulumi programs.

Deploying the Example

Prerequisites

1. Install Pulumi
2. Configure Pulumi for AWS
3. Configure Pulumi for Python

Part 1: Privileged Components

The Pulumi program in create-role requires credentials with permissions to create an IAM User, an IAM Role, and assign an AWS Access Key to the user. The program creates a new, unprivileged user with no policies attached, and a role which specifies a trust policy allowing assumption by the unprivileged user. The role allows the s3:* actions on all resources.

You’ll need to set the create-role:unprivilegedUsername configuration variable to the name of the unprivilged user, as well as the AWS region in which to operate.

First, you need to create a new stack:

$ cd create-role
$ pulumi stack init assume-role-create
$ pulumi config set create-role:unprivilegedUsername somebody@pulumi.com
$ pulumi config set aws:region us-east-1
$ pulumi up

The program can then be run with pulumi up. The outputs of the program tell you the ARN of the Role, and the Access Key ID and Secret associated with the User:

$ pulumi stack output --json
{
  "accessKeyId": "AKIAYJ7EUPHL3DSDH4CX",
  "roleArn": "arn:aws:iam::571173272023:role/allow-s3-management-fcc71c0",
  "secretAccessKey": [secret]
}

If we just use the above command then the secretAccessKey would not be shown. In order to show the secret value use this

$ pulumi stack output --json --show-secrets
{
  "accessKeyId": "AKIAYJ7EUPHL3DSDH4CX",
  "roleArn": "arn:aws:iam::571173272023:role/allow-s3-management-fcc71c0",
  "secretAccessKey": "[plain text value]"
}

Part 2: Assuming the Role

The Pulumi program in assume-role creates an S3 bucket after assuming the Role created in Part 1. It should be run with the unprivileged user credentials created in Part 1. This can be configured as follows, from the assume-role directory, replacing {YOUR_STACK_PATH/assume-role-create} with the full name of your stack from Part 1. Full name of your stack is available at app.pulumi.com

$ cd ../assume-role
$ export AWS_ACCESS_KEY_ID="$(pulumi stack output --stack {YOUR_STACK_PATH/assume-role-create} accessKeyId)"
$ export AWS_SECRET_ACCESS_KEY="$(pulumi stack output --stack {YOUR_STACK_PATH/assume-role-create} --show-secrets secretAccessKey)"

The configuration variable roleToAssumeARN must be set to the ARN of the role allowing S3 access, and the AWS region must be set to the region in which you wish to operate:

$ pulumi stack init assume-role-assume
$ pulumi config set roleToAssumeARN "$(pulumi stack output --stack {YOUR_STACK_PATH/assume-role-create} roleArn)"
$ pulumi config set aws:region us-east-1

Unset the AWS_SESSION_TOKEN or any additional credential setting if you have set for previous access

$ unset AWS_SESSION_TOKEN

The program can then be run with pulumi up. You can verify that the role is indeed assumed by looking at the CloudTrail logs of the bucket creation operation, or by commenting out the assumeRole configuration in the provider and ensuring creation is not successful.

Clean up

To clean up your resources, run pulumi destroy and respond yes to the confirmation prompt.