Swarm-agent reports no such host failure after start

Rancher 1.x
1

The issue appears when I’m setting up a swarm environment with the catalog hanging in state of launching services (1/2).
Then the following error was found after I checked docker logs of swarm-agent, one of the 2 services to be brought up:

time="2016-09-08T06:37:23Z" level=info msg="Listening for health checks on 0.0.0.0:10240/healthcheck" time="2016-09-08T06:37:23Z" level=error msg="Rancher stream listener exited with error: Get http://docker-rancher:8080/v1: dial tcp: lookup docker-rancher on 169.254.169.250:53: no such host" time="2016-09-08T06:37:23Z" level=info msg=Exiting.

The segment repeats itself every 30 seconds and thus the service kept stuck in “activating”. It seems that swarm-agent is trying to connect to rancher but name resolution keeps failing.
As I put rancher on the same host of rancheros I think it should just connect to 0.0.0.0:8080. How should I adjust related configs to make it work?

2

Resolved by replacing the hostname of rancher server with its FQDN.
Seems rancher agent DNS cannot resolve host without DN by itself, although domain name config does exist in /etc/resolv.conf when I was checking agent container.