manylinux-ubuntu

This is only a PoC that serves multiple purposes:

• experiment with multiarchitecture images in GHA
• provide a path to build armv7l manylinux wheels
• provide a path to build riscv64 manylinux wheels

Why this won't be part of pypa/manylinux as a whole

If you're building manylinux wheels for x86_64, aarch64, ppc64le or s390x then, the already existing images based on RHEL derivatives are better suited for the job. They do provide compatibility with older systems while providing a recent gcc toolchain. As an example, the manylinux_2_28 image that ensure built wheels will run on glibc 2.28+ systems currently provides a gcc 13 toolchain. A manylinux_2_35 image based on Ubuntu 22.04 would only ensure compatibility with more recent glibc 2.35+ systems while providing an older gcc 11 toolchain.

This linked issue has more information about this.

Path to build armv7l manylinux wheels

armv7l is still used nowadays, for example on Raspberry Pi. There are no RHEL derivatives for this architecture that would allow for "old systems with a recent toolchain" out-of-the-box.

As such, one way forward is to have a Debian derivative image that allows building manylinux wheels for this architecture. This comes with some caveats:

• in order to achieve compatibility with "older" systems, you get an older toolchain:
  • gcc9 on Ubuntu 20.04 (manylinux_2_31 wheels compatible with Ubuntu 20.04+, Debian 11+)
  • gcc11 on Ubuntu 22.04 (manylinux_2_35 wheels compatible with Ubuntu 22.04+, Debian 12+)
• the package manager & packages names are different than what is found on pypa/manylinux images: pypa/manylinux images are using RHEL derivatives only for now so using yum/dnf as a package manager and RHEL like packages names while images here are using apt and Debian like packages names. If one depends on let's say OpenSSL development package, then, the commands to issue to install it are a bit different:
  • dnf -y install openssl-devel on RHEL derivatives
  • apt-get update && apt-get install -y libssl-dev on Debian derivatives

An experiment has been proposed in pypa/cibuildwheel using the manylinux_2_31 image from this repository as a first step towards supporting armv7l manylinux wheel building.

If the experiment proves successful, a specific armv7l image will be added in pypa/manylinux.