Locust insists on using IPv6 despite being in an IPv4 stack.

[axot]

Prerequisites

• I am using the latest version of Locust
• I am reporting a bug, not asking a question

Description

I have an environment that is IPv4-only, but there is an IPv6 address listed in /etc/hosts. When I try to connect to the master using the following command, it results in an error:

# locust -f ./p4_basic_code.py --worker --master-host locust-master -L DEBUG
[2024-04-25 06:24:31,138] ip-192-168-0-235.ap-northeast-3.compute.internal/DEBUG/locust.runners: Failed to connect to master locust-master:5557, retry 1/60.

By changing self.socket.setsockopt(zmq.IPV6, 1) to 0 resolves the issue.

# cat /etc/hosts
127.0.0.1 localhost
192.168.0.235 ip-192-168-0-235.ap-northeast-3.compute.internal
127.255.0.1 locust-master
2600:f0f0:0:0:0:0:0:1 locust-master

I recommend detecting whether the current environment supports IPv6 before enabling it.

Command line

locust -f ./p4_basic_code.py --worker --master-host locust-master -L DEBUG

Locustfile contents

N/A

Python version

3.11

Locust version

2.26.0

Operating system

Debian 12

[cyberw]

Latest locust version is 2.26, start by updating. If that doesnt work, maybe you could provide a PR?

[axot]

Hi, I've verified that the issue persists in the latest version 2.26.0. I'll check if I can submit a pull request."

[axot]

FYI, use version 2.20.0 as a temporary solution.

[cyberw]

Can you try out the suggested fix and see if it works for you? (pip install --pre -U locust)