Synchronization techniques for computing systems that interface with external service providers. A method for accessing status and other attributes of an external service provider commences upon identifying an external service such as a firewall appliance or backup repository that provides computing-related functions to computing entities of the computing system. One or more access mechanisms such as an application programming interface is exposed to the external service. The external service is registered with the computing system to use the access mechanism. When the external service detects a change of its state, the external service can communicate that change to the computing system through a “push” operation. The computing system processes the “pushed” data from the external service by verifying the status of the registration and authorization permissions, and then modifies one or more entity attributes of the computing resource entity.