Github user zhangminglei commented on the issue: https://github.com/apache/flink/pull/5449 Thank you for your response, @StephanEwen You are very correct. We would not connect JM / RM / ZK if we use ```getByName("localhost")``` . I will give an example based I have known about this issue. We still can't believe ```getLocalHost()``` too much , as the file ```/etc/hosts``` once change the mapping of host name to an IP. That will cause a problem after that. And we will get different value( that you set the mapping including this value) Below is my machine about this file, and I can always get a correct stuff of ```ricezhang-pjhzf.vclound.com/10.199.203.242``` that works for my network if I do not set that manually. ``` 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 ``` Once I modify that file like below though, I will always get an **incorrect** value, because ```192.168.1.1``` is a a fake address. and will cause some issue. ``` 127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4 ::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 192.168.1.1 ricezhang-pjhzf.vclound.com ``` As refers to this **instability** test, **I don't know if something dynamically modified that file on Travis** ? Or something like that ? Even if not, we also CAN NOT rely on this method to get a IP that can connect to. Once the ```Zookeeper``` records the incorrect IP address, this will cause error. We can not get a correct IP to connect to what we want. I agree with retry or a better test ( I do not know at this moment ) approach, I will study this issue in depth in these days.