Problem

The error Unable to locate credentials is returned when attempting to install an AWS StackPack instance with use-role set for the Access Key ID and Secret Access Key.

Cause

When use-role is specified, the AWS StackPack instance will attempt to assume the IAM role attached to the EC2 instance where StackState runs to retrieve metrics from CloudWatch. If the correct policy is not attached to this role, the Unable to locate credentials error will be returned.

Solution

To resolve the error:

1. Click UNINSTALL to uninstall the StackPack instance reporting the error.
2. Set up the IAM role for the StackState EC2 instance.
3. Install the AWS StackPack again.