This paper presents QuoCast, a resource-aware protocol for reliable stream diffusion in unreliable environments, where processes may crash and communication links may lose messages. QuoCast is resource-aware in the sense that it takes into account memory, CPU, and bandwidth constraints. Memory constraints are captured by the limited knowledge each process has of its neighborhood. CPU and bandwidth constraints are captured by a fixed quota on the number of messages that a process can use for streaming. Both incoming and outgoing traffic are accounted for. QuoCast maximizes the probability that each streamed packet reaches all consumers while respecting their incoming and outgoing quotas. The algorithm is based on a tree-construction technique that dynamically distributes the forwarding load among processes and links, based on their reliabilities and on their available quotas. The evaluation results show that the adaptiveness of QuoCast to several contraints provides better reliability when compared to other adaptive approaches.