PyPI — a repository of python modules. apt is used to download and install packages from Ubuntu repositories

In ubuntu repository packages available only for selected python modules. but in , PyPI repository a much broader range of python modules. So, there are a lot of python modules which you won't be able to install using apt.

In ubuntu repository, generally, the latest version package or the one released latest. So, in apt ubuntu repository, we cannot able to specify the version of python-package that we need. but using pip we can install specific version the of package we need.

if we use apt, the modules install in the system-wide location, we are not able to install into the virtualenv. but, the pip will solver this probelm.

In your scenario, there will be a prerequisite required, Currently, the clients do not support Python 3. https://docs.openstack.org/newton/use...