Hi,
You'll want to set server.host in your kibana.yml. If you don't, Kibana will default to only binding to localhost. The important part to that is that the container is its own "localhost", so the default value will only allow Kibana to be seen from inside the container, which is clearly not what you want.
That's why, in the default config, we set server.host to 0 (shortcut for 0.0.0.0).