A service registers multiple instances on consul through coding. Why can grpc only call the service configured in the configuration file.

[liq0221]

A service registers multiple instances on consul through coding. Why can grpc only call the service configured in the configuration file.

[ST-DDT]

I'm somewhat confused with your question.
The service will use the address from the config file, that might be one or more hardcoded addresses or a dynamic address such as dns or a service discovery.
See also here: https://grpc-ecosystem.github.io/grpc-spring/en/client/configuration.html#choosing-the-target
Have a look at the discovery scheme.