  When deploying mission-critical systems in the cloud, where deviations may
have severe consequences, the assurance of critical decisions becomes
essential. Typical cloud systems are operated by third parties and are built on
complex software stacks consisting of e.g., Kubernetes, Istio, or Kafka, which
due to their size are difficult to be verified. Nevertheless, one needs to make
sure that mission-critical choices are made correctly. We propose a flexible
runtime monitoring approach that is independent of the implementation of the
observed system that allows to monitor safety and data-related properties. Our
approach is based on combining distributed Datalog-based programs with
tamper-proof storage based on Trillian to verify the premises of
safety-critical actions. The approach can be seen as a generalization of the
Certificate Transparency project. We apply our approach to an industrial use
case that uses a cloud infrastructure for orchestrating unmanned air vehicles.
