You have the option of running Tutor with `Podman <https://podman.io/>`__, instead of the native Docker tools. This has some practical advantages: it does not require a running Docker daemon, and it enables you to run and build Docker images without depending on any system component running ``root``. As such, it is particularly useful for building Tutor images from CI pipelines.
The ``podman`` CLI aims to be fully compatible with the ``docker`` CLI, and ``podman-compose`` is meant to be a fully-compatible alias of ``docker-compose``. This means that you should be able to use together with Tutor, without making any changes to Tutor itself.
Since this was written, it was discovered that there are major compatibility issues between ``podman-compose`` and ``docker-compose``. Thus, podman cannot be considered a drop-in replacement of Docker in the context of Tutor -- at least for running Open edX locally.
You should not attempt to run Tutor with Podman on a system that already has native ``docker`` installed. If you want to switch to ``podman`` using the aliases described here, you should uninstall (or at least stop) the native Docker daemon first.
Podman is supported on a variety of development platforms, see the `installation instructions <https://podman.io/getting-started/installation>`_ for details.
Once you have installed Podman and its dependencies on the platform of your choice, you'll need to make sure that its ``podman`` binary, usually installed as ``/usr/bin/podman``, is aliased to ``docker``, and is included as such in your system ``$PATH``. On some CentOS and Fedora releases you can install a package named ``podman-docker`` to do this for you, but on other platforms you'll need to take of this yourself.
- If ``$HOME/bin`` is in your ``$PATH``, you can create a symbolic link there::
ln -s $(which podman) $HOME/bin/docker
- If you want to instead make ``docker`` a system-wide alias for ``podman``, you can create your symlink in ``/usr/local/bin``, an action that normally requires ``root`` privileges::
``podman-compose`` is available as a package from PyPI, and can thus be installed with ``pip``. See `its README <https://github.com/containers/podman-compose/blob/devel/README.md>`_ for installation instructions. Note that if you have installed Tutor in its own virtualenv, you'll need to run ``pip install podman-compose`` in that same virtualenv.
Once installed, you'll again need to create a symbolic link that aliases ``docker-compose`` to ``podman-compose``.
- If you run Tutor and ``podman-compose`` in a virtualenv, create the symlink in that virtualenv's ``bin`` directory: activate the virtualenv, then run::
Once you have configured your symbolic links as described, you should be able to run ``docker version`` and ``docker-compose --help`` and their output should agree, respectively, with ``podman version`` and ``podman-compose --help``.
After that, you should be able to use ``tutor local``, ``tutor build``, and other commands as if you had installed the native Docker tools.
