Credentials are automatically resolved by the SDK. The order of precedence when resolving credentials is:

1. Static Credentials
2. Environment Credentials
3. Shared Credentials
4. Instance Profile Credentials

Credentials provided in code using AWS Options are "Static Credentials".

Environment credentials are provided via the environment variables AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, and AWS_SESSION_TOKEN.

When running on an Elastic Compute Cloud (EC2) instance or inside an Elastic Container Service (ECS) instance, credentials will be automatically sourced from the instance profile.