Failure detectors are basic building blocks from which fault tolerance for distributed systems is constructed. The Quality of Service (QoS) of failure detectors refers to the speed and accuracy of detections and is defined from the applications and computing environment under consideration. Existing failure detection approaches for distributed systems do not support the automatic (re)configuration of failure detectors from QoS requirements. However, when the behavior of the computing environment is unknown and changes over time, or when the application itself changes, self-configuration is a basic issue that must be addressed - particularly for those applications requiring response time and high availability requirements. In this paper we present the design and implementation of a novel autonomic failure detector based on feedback control theory, which is capable of self-configuring its QoS parameters at runtime from previously specified QoS requirements.