An automated arrangement for deploying software updates to a distributed system based on state differences is provided in which a manifest defines a target snapshot of the desired state of the system after it is updated. A snapshot of the current distributed system state is taken and a state difference between the current state and the target state is calculated. A rule-based engine applies pre-defined rules to generate a sequence of actions that when performed will bring the distributed system to the target state. Accordingly, rather than have to focus on how to change the distributed system, software developers and system administrators may instead specify the target distributed system state in the manifest and the present automated deployment arrangement will perform the required actions to deploy the updates and achieve the desired state.