Ansible, pip and virtualenv

[Albert-Jan Roskam]

   Hi
   I wrote an Ansible .yml to deploy a Flask webapp. I use python 3.6 for the
   ansible-playbook executable. The yml starts with some yum installs,
   amongst which python-pip. That installs an ancient pip version (v9). Then
   I create a virtualenv where I use a requirements.txt for pip install -r.
   Should I precede that step with a separate --upgrade pip step? Or should
   pip just be in my requirements.txt?
   Separate question: what locations do I need to specify in my pip
   --trusted-host list? Could it be that this has recently changed? I
   suddenly got SSL errors.
   Thanks in advance!
   Albert-Jan