--master-host only accepts ipv4 formatted strings

Description of issue / feature request

When setting up a distributed setup via docker-compose, I’d like to set the master-host to the locust_master service name. However, it seems that non-ipv4 formatted strings cause an error and crashes the slave. This is an example of what I would like to do (but causes the slave to crash with a ZMQError):

services:
version: '2.1'
services:
  locust_master:
    build: .
    ports:
      - "8081:8081"
    volumes:
      - '.:/src'
    command:
      'locust'

  locust_workers:
    build: .
    command:
      'locust  --slave --master-host=locust_master'
    depends_on:
      - locust_master

Expected behavior

It connects to the host via it’s alias’ed hostname.

Actual behavior

It crashes with a ZMQError

Environment settings (for bug reports)

• OS: Red Hat Enterprise Linux 7
• Python version: 2.7
• Locust version: Stable

Steps to reproduce (for bug reports)

Create a dockerfile with locust and then try to bring up a master / slave where --master-host is set to locust_master

[kasturichavan]

@cgoldberg @aldenpeterson-wf Is there no other way than hardcoding an ipaddress to get this working ? When we deploy this in kubernetes, hardcoding ipadress will be a pain.

[cyberw]

Closing this, if it was not a zeromq bug please reopen with a more descriptive title.