vCloud Director uses a message bus architecture for communicating vCloud Director events with third-party systems or services. Events fall into two classes, non-blocking and blocking. In the case of non-blocking events, vCloud Director publishes every action taken as a message to the configured exchange queue. Non-blocking messages do not halt the generating task and the task continues on regardless of what processing or acknowledgement is done on the event message.

Non-blocking and blocking event messages are not multitenant in nature and are not exposed to the tenant layer of the cloud. They are inherently intended for use by the cloud provider and not the tenant.