node graph

problem: Cann't find node info when running node in in-docker env.

case 1: in-docker

in-docker$ python talker.py
[info]  node_name = /talker_17328_1562752752991  node_uri = http://172.17.0.1:34267/ 
...
$ rosnode list
/rosout
/rosout_agg

case 2: out-docker

$ python talker.py
[info]  node_name = /talker_17722_1562753684575  node_uri = http://robin-ZHAOYANG-K42-80:36603/
...
$ rosnode list
/chatter
/rosout
/rosout_agg

No matter roscore is launched in in-docker env.(at http://172.17.0.1:36273/) or in out-docker env (at http://robin-ZHAOYANG-K42-80:11311/ ), we cannot find talker node info in case 1?

The test script talker.py is almost like code here