New and more advanced applications are supporting end-to-end quality-of-service (QoS) guarantees through the configuration and management of distributed resources. As an effect of the sharing of static resources across multiple concerns, coupled with the use of dynamically changing resources such as mobile communications, the general availability of resources in a distributed environment is variable and potentially unpredictable. In this paper, we discuss the requirements for QoS adaptation mechanisms and QoS-based distributed resource management, together with our approaches to QoS monitoring and adaptation, in the context of our recently developed Distributed Resource Management Architecture (DRMA).