Installing Ansible on a RISC-V computer

Ansible runs on Python, and Python runs on... well pretty much everything. Including newer RISC-V machines.

But Ansible has a lot of dependencies, and some of these dependencies have caused frustration from time to time on x86 and Arm (so having issues with a dependency is just a way of life when you enter dependency hell)... but in this case, for the past few months, I've never had luck installing Ansible from PyPI (Python's Package Index) on any RISC-V system, using pip install ansible.

I prefer installing this way (rather than compiling from source or from system packages) because it generally gets the latest version of Ansible, with an easy upgrade/downgrade path. It's also easy to add ansible to a Python requirements.txt file and install it alongside other package dependencies.

Regardless, the cryptography library, which requires a Rust compiler to build if the package is not already built for a particular system, has made it difficult to install Ansible from pip:

      copying src/cryptography/hazmat/bindings/_rust/openssl/x448.pyi -> build/lib.linux-riscv64-cpython-310/cryptography/hazmat/bindings/_rust/openssl
      running build_ext
      running build_rust
      error: can't find Rust compiler

      If you are using an outdated pip version, it is possible a prebuilt wheel is available for this package but pip is not able to install from it. Installing from the wheel would avoid the need for a Rust compiler.

      To update pip, run:

          pip install --upgrade pip

      and then retry package installation.

      If you did intend to build this package from source, try installing a Rust compiler from your system package manager and ensure it is on the PATH during installation. Alternatively, rustup (available at https://rustup.rs) is the recommended way to download and update the Rust compiler toolchain.

      This package requires Rust >=1.63.0.
      [end of output]

  note: This error originates from a subprocess, and is likely not a problem with pip.
  ERROR: Failed building wheel for cryptography
  Building wheel for MarkupSafe (setup.py) ... done
  Created wheel for MarkupSafe: filename=MarkupSafe-2.1.5-cp310-cp310-linux_riscv64.whl size=23821 sha256=da37d67f972b1023bca608d3c5a2038e1f99061240ccd1a57a2d9a30baeddf3d
  Stored in directory: /home/user/.cache/pip/wheels/2a/04/fa/f54a9011eaf18a437110e8171478b3e963dc249ed60ce77f17
Successfully built PyYAML MarkupSafe
Failed to build cryptography
ERROR: Could not build wheels for cryptography, which is required to install pyproject.toml-based projects

See this GitHub issue for a bit more.

After posting about this on Twitter/X, user @mediocreDevops followed up with a solution, which he details in this GitHub Gist.

I followed along and tried to do this on a Milk-V Mars SBC I'm testing currently (see test results here), and here's how I tried installing it:

1. Install rustup: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh (choose the 'default' option)
2. Make sure your shell has the rust env vars added: . "$HOME/.cargo/env" (or log out and back in)
3. Make sure other dependencies are installed: sudo apt install -y pkg-config python3-pip
4. Install Ansible: pip3 install ansible

Unfortunately, it was locking up, so I rebooted and tried again, but it errored out with IndexError: list index out of range since it seemed to be trying to get Rust's version and failing. rustc --version was returning nothing, so I reinstalled rust:

user@milkv:~$ rustup uninstall stable
...
user@milkv:~$ rustup install stable

After doing that, I tried installing ansible yet again:

user@milkv:~$ rustc --version
rustc 1.79.0 (129f3b996 2024-06-10)
user@milkv:~$ pip3 install ansible
...
Successfully installed MarkupSafe-2.1.5 PyYAML-6.0.1 ansible-10.1.0 ansible-core-2.17.1 cffi-1.16.0 cryptography-42.0.8 jinja2-3.1.4 packaging-24.1 pycparser-2.22 resolvelib-1.0.1
user@milkv:~$ export PATH=$PATH:/home/user/.local/bin
user@milkv:~$ ansible --version
ERROR: Ansible could not initialize the preferred locale: unsupported locale setting

Running it with a locale environment variable Ansible is happy with (see this issue for more details):

user@milkv:~$ LC_ALL="C.UTF-8" ansible --version
ansible [core 2.17.1]
  config file = None
  configured module search path = ['/home/user/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /home/user/.local/lib/python3.10/site-packages/ansible
  ansible collection location = /home/user/.ansible/collections:/usr/share/ansible/collections
  executable location = /home/user/.local/bin/ansible
  python version = 3.10.9 (main, Dec  7 2022, 13:47:07) [GCC 12.2.0] (/usr/bin/python3)
  jinja version = 3.1.4
  libyaml = False

So we got it going... eventually. Hopefully as RISC-V becomes a bit more widespread, things like more universal wheels will exist in that ecosystem like they do Arm today. And if not, hopefully installation of things like the Rust language become a little simpler / more stable!