p>To simplify the system and improve developer experience, Istio uses
shared attribute definitions across all components. For example, the same
authenticated user attribute will be used for logging, monitoring, analytics,
billing, access control, auditing. Many Istio components provide their
functionality by collecting, generating, and operating on attributes.
For example, the proxy collects the error code attribute, and the logging
stores it into a log.</p><h3 id=design>Design</h3><p>Each Istio attribute m