WowRegistrationMetadata

Gives the registration of this node in the application's service registry its WowInstanceMetadata: its service and the address it advertises to its members (ServiceNode.address), so a peer that looks the service up there reaches its internal port. Spring Cloud announces the registration (InstancePreRegisteredEvent) just before it registers it, once the public server is up, so after the node has bound its internal port, a port the system chose included.

Consul, Nacos and Zookeeper send the registration's metadata as it is when they register it, so it is written there; Eureka copies it when its instance's bean is built, so it is given to Eureka's ApplicationInfoManager too, and Zookeeper builds its instance on first use, so it is built first. A registration whose metadata takes no entry fails the start: its peers would never find the node.