Why does Ray attempt to install ray wheels from ray-wheels.s3-us-west-2.amazonaws.com?

1. Severity of the issue: (select one)
None: I’m just curious or want clarification.
Low: Annoying but doesn’t hinder my work.
Medium: Significantly affects my productivity but can find a workaround.
High: Completely blocks me.

2. Environment:

  • Ray version: 2.20.0
  • Python version: 3.11.9
  • OS: Ubuntu 22.04.5 LTS
  • Cloud/Infrastructure: Azure
  • Other libs/tools (if relevant): conda

3. What happened vs. what you expected:

  • Expected: Ray installs ray wheel from custom Python package index (Artifactory)
  • Actual: Ray ignores pip configuration and attempts to install ray from ray-wheels.s3-us-west-2.amazonaws.com

For full transparency: I already posted this question on SO before I learned about the existence of this forum.

When submitting a Ray job using a conda runtime env (runtime_env = {"conda": "environment.yml"}), Ray attempts to install the ray wheel from ray-wheels.s3-us-west-2.amazonaws.com even when I configure pip to use a different Python package index (--index-url). Example environment.yml:

name: test
channels:
  - https://conda.anaconda.org/conda-forge/
  - nodefaults

dependencies:
  - pandas=2.2.3
  - pip
  - pip:
      - --index-url https://artifactory.company.com/artifactory/api/pypi/pypi-remote/simple/
      - ray==2.20.0

Ray seems to ignore the provided configuration and attempt to install the ray wheel from ray-wheels.s3-us-west-2.amazonaws.com. Is there a configuration setting to change this behavior or how can ray be installed from a custom Python package index without having to go out to the Internet?