Need to use external ip or hostname when connecting from client application

[sripri]

I have followed your compose and scripts closely. However, when connecting from a java (spring boot app in my case) I discovered that the config setup for the repl set needs to be the hostname of the machine (or the external IP address). for example,
config= {"_id": "mongors", members:[{"_id": 0, "host": "external-hostname::27017", "priority": 2},{"_id": 1, "host": "external-hostname:27018", "priority": 0},{"_id": 2, "host": "external-hostname:27019", "priority": 0}]}

If I dont and instead give it the docker's internal ip address it does not work. I get a connection error (looks like the hearbeat checks against the address specified in the config variable.