Support building Linux wheels without Docker/Podman when already running inside a manylinux container

[Laky-64]

Description

I'm using a custom manylinux-based container image in CI.

The environment already contains:

• the manylinux userspace
• all required Python interpreters
• the complete build toolchain

When running cibuildwheel inside that container, it still requires a container engine (docker or podman) and attempts to launch a nested manylinux container.

This fails in environments where Docker is unavailable, for example:

• GitHub Actions container jobs
• some self-hosted runners
• restricted CI environments

Question

Is there currently any supported way to tell cibuildwheel:

"I am already running inside a valid manylinux container, please build directly in the current environment without spawning another container."

Something like a native/containerless Linux mode.

Motivation

This would allow projects that already maintain custom manylinux images to:

• avoid Docker-in-Docker
• avoid Podman setup
• reduce CI complexity
• reuse existing build environments directly

If this is intentionally unsupported, could you explain the main technical or policy reasons behind that decision?

Thanks!