1. A method, comprising: in a cloud computing system having system domains including a storage domain, a network domain, a compute domain, and a virtual layer, which comprises a virtualization server, a virtualization application, and a data store application; receiving a first alert in a first domain of the system domains and a second alert in a second domain of the system domains, the first and second alerts caused by a first event in the first domain and receiving a third alert in the virtual layer; determining a topology of the system including physical and logical connections for components in the storage, network, compute domains, and the virtual layer, wherein the topology comprises topology objects; performing, using a computer processor, connectivity matching to identify connections between ports in the first domain and ports in the second domain for port-to-port connectivity between components in the first and second domains; performing identity matching, using unique identifiers for domain components that are hardware components, to determine that a first component in the first domain associated with the first alert is the same component as a second component associated with the second alert in the second domain for cross domain event correlation; maintaining intra-domain relationships by periodically querying the components in the system domains; receiving alerts for a second event that is caused by and related to the first event; performing state updates by mapping the first and second alerts to respective states of ones of the topology objects, wherein the first and second events correspond to respective states of the ones of the topology objects; and querying at least one of the first and second events to determine that the second event is explained by the first event.