Failures in a distributed system are not only possible but expected and notoriously difficult to handle. For this reason, it is imperative to provide system-level means for building failure-transparent services, i.e., services which transparently recover from failures, effectively masking them. Towards this, this paper presents a syntax and semantics for compositionally failure-transparent actors. It is structured around three kinds of failure-transparent compositions: composition within a system; between systems; and application-level composition. For the former two, we prove that the semantics is failure transparent by simulation using prophecy variables. For the latter, we discuss its implementation; additionally, we discuss the necessity for leaking system-level failures to the application-level. The presented material provides low-level building blocks for failure-transparent services, thus greatly simplifying their construction
Acknowledgments. The authors would like to thank the anonymous reviewers for their helpful comments. This study was partially funded by Digital Futures under a Research Pairs Consolidator grant (PORTALS).