alpine: py-pip has been renamed to py2-pip
FYI
Here: https://github.com/William-Yeh/docker-ansible/blob/master/alpine3/Dockerfile#L20 , the py-pip package is installed using apk on the alpine flavour:
apk --update add python py-pip openssl ca-certificates && \
However AFAIK, the py-pip package was at some point in the past renamed to simply py2-pip. Therefore I would suspect this action to fail on your alpine builds.
py-pip search: NO RESULTS
https://pkgs.alpinelinux.org/packages?name=py-pip&branch=edge
It looks like this happened as of alpine version 3.4
py-pip search: YIELDS RESULTS
https://pkgs.alpinelinux.org/packages?name=py-pip&branch=v3.4&arch=x86_64
vs.
py-pip search: NO RESULTS
https://pkgs.alpinelinux.org/packages?name=py-pip&branch=v3.5&arch=x86_64
vs.
py2-pip search: YIELDS RESULTS
https://pkgs.alpinelinux.org/packages?name=py2-pip&branch=v3.5&arch=x86_64
on an unrelated note, there is no py3-pip, as it comes in the python3 package
https://pkgs.alpinelinux.org/package/v3.5/main/x86_64/python3