Got no such host error in compose and go-machine in HA startup

For rancher-compose-executor:
time=“2016-09-27T06:14:47Z” level=fatal msg="exit status 1"
time=“2016-09-27T06:15:01Z” level=info msg="Listening on"
time=“2016-09-27T06:15:01Z” level=info msg="Forwarding setup to: :80"
time=“2016-09-27T06:15:02Z” level=info msg="Listening on port: 80"
time=“2016-09-27T06:15:02Z” level=info msg=“Starting rancher-compose-executor” version=v0.8.6
time=“2016-09-27T06:15:02Z” level=fatal msg=“Unable to create event router” error="Get http://haproxy01/v1: dial tcp: lookup haproxy01 on no such host"
time=“2016-09-27T06:15:02Z” level=fatal msg=“exit status 1”

For go-machine-service:
time=“2016-09-27T06:12:25Z” level=info msg="Listening on"
time=“2016-09-27T06:12:25Z” level=info msg="Forwarding setup to: :80"
time=“2016-09-27T06:12:26Z” level=info msg="Listening on port: 80"
time=“2016-09-27T06:12:26Z” level=info msg=“Setting log level” logLevel=info
time=“2016-09-27T06:12:26Z” level=info msg=“Starting go-machine-service…” gitcommit=v0.31.7
time=“2016-09-27T06:12:26Z” level=info msg="Waiting for handler registration (1/2)"
time=“2016-09-27T06:12:26Z” level=fatal msg="Exiting go-machine-service: Get http://haproxy01/v1: dial tcp: lookup haproxy01 on no such host"
time=“2016-09-27T06:12:26Z” level=fatal msg=“exit status 1”

haproxy01 is the external load balancer for 3 rancher-server nodes.
I’m wondering if anybody could offer clues on how to look into the lookup failure on The name can be correctly resolved in rancherOS which hosts docker service.

Resolved the same way with Swarm-agent reports no such host failure after start