An architectural description to capture dynamic aspects of software architecture provides the fundamental information to the external adaptation mechanism for self-adaptive systems. This paper presents a dAcme framework for distributed self-adaptive systems and introduces an architecture description language to address the dynamism of software architecture. In dAcme, the traditional model layer is separated into model and instance layers. Multi-domain constraints and self-adaptive tactics are extended based on basic Acme syntax. These extensions turn the analyzing and planning phase of the adaptation life circle into searching a solution for distributed constraint satisfactory problems. A media distribution case study is presented to demonstrate the expressiveness of the proposed approach