Dependable service components selection is the key to implement dependability assurance in distributed virtualized environment.The service components selection can be modeled as Multi-Constrained Optimal Path(MCOP) problem

and service components will be selected by searching trust path.However

existing trust path search algorithms have disadvantages of high complexity and low performance.And the researches about modeling dependable service components selection lack the consideration of trust relationships and evidence spread among service components during service construction and composition.Therefore

we proposed the concept of QoD

the Quality of Dependability

introducing the attributes(e.g.componentintimacy) to describe and restrict the model of service components selection in distributed virtualized environment.We also designed a heuristic optimal trust service path search algorithm HA_OTPS

and chose service components on the optimal trust service path to satisfy users' demand for service dependability.The experimental results showed that HA_OTPS has shorter execution time and higher utility of search results than the existing trust path search algorithms.