Summary

After the web identity test detaches the host's EC2 instance profile, the auth_aws teardown tries to put it back, but the call fails with InvalidInstanceID.NotFound. The script runs with the task's secrets-role credentials, which belong to a different AWS account than the host, so the instance is invisible to it. The teardown should clear the ambient AWS credentials before the script picks up its own, as the setup script already does.

Motivation

Who is the affected end user?

Driver teams running the MONGODB-AWS auth tests on Evergreen, and the drivers-evergreen-tools maintainers reading the task logs.

How does this affect the end user?

Mildly confused. A traceback appears in the task logs even though the task passes, and the host is left without its instance profile.

How likely is it that this problem or use case will occur?

Every run that reaches teardown after the web identity test. Observed on Windows hosts; the cause is not specific to Windows.

If the problem does occur, what are the consequences and how severe are they?

The error is swallowed, so tasks still pass and the instance profile is not restored. Minor if hosts are not reused after the task.

Is this issue urgent?

No.

Is this ticket required by a downstream team?

No.

Is this ticket only for tests?

Yes. It only affects the test teardown script.

Acceptance Criteria

• The auth_aws teardown restores the host's instance profile after the web identity test, with no error in the task log.
• Verified on Linux and Windows Evergreen hosts.