Validating distributed systems is particularly difficult, since failures may occur due to a correlated occurrence of faults in different parts of the system. This paper describes the basis for and preliminary implementation of a new fault injector, called Loki, developed specifically for distributed systems. Loki addresses issues related to injecting correlated faults in distributed systems. In Loki, fault injection is performed based on a partial view of the global state of an application. In particular, facilities are provided to pass user-specified state information between nodes to provide a partial view of the global state in order to try to inject complex faults successfully. A post-runtime analysis, done using an off-line clock synchronization and a bounding technique, is used to place events and injections on a single global timeline and determine whether the intended faults were properly injected. Finally, observations containing successful fault injections are used to estima...