Poor performance of Python socket module on MacOS 15 runner

[MetRonnie]

Description

socket.getfqdn() is taking more than 1 minute to run for some reason!

Platforms affected

• Azure DevOps
• GitHub Actions - Standard Runners
• GitHub Actions - Larger Runners

Runner images affected

• Ubuntu 22.04
• Ubuntu 24.04
• macOS 13
• macOS 13 Arm64
• macOS 14
• macOS 14 Arm64
• macOS 15
• macOS 15 Arm64
• Windows Server 2019
• Windows Server 2022
• Windows Server 2025

Image version and build link

macos-15-arm64 20250428.1341

https://github.com/MetRonnie/muldoon/actions/runs/14890924049/job/41822518502

Is it regression?

Yes, see macos-14-arm64 20250505.1431 run: https://github.com/MetRonnie/muldoon/actions/runs/14890924049/job/41822518514

Expected behavior

socket.getfqdn() should take ~1s or less

Actual behavior

It's taking more than 1 minute to run.

Repro steps

- shell: python
  run: |
    import socket
    socket.getfqdn()

(I have checked that import socket does not take an undue amount of time by running it alone in a different step)

[aartis17]

Hi @MetRonnie, We will look into the issue and keep you posted with updates. Thanks.

[aartis17]

Hi @MetRonnie,
I have reviewed the workflow you provided and observed that socket.getfqdn() takes more than 1 minute to execute on the macos-15 image. However, on the macos-15-large image with 3.9 python version, it executes in seconds.
please see below snip:

• macos-15-large image with 3.9 python version :

• For workaround , you can use the command socket.gethostname() along with import socket for faster execution.

We are continuing to investigate the root cause of the delay when using socket.getfqdn() on the macOS-15 image. Thank you for your patience!

[aartis17]

Hi @MetRonnie, Following up on my previous comment regarding error on macOS-15 runners, have you had a chance to review the information and the suggested recommendation above? Thanks.

[MetRonnie]

We are currently not using MacOS-15 runners (I think macos-latest is still 14?) so happy to wait for a fix. Changing our usage of socket in our application due to performance problems on one GH Actions system is a no-go, however

[aartis17]

@MetRonnie 👋
Thank you for your patience. We are still investigating the issue, stay tunned. Thanks.