[mugsie]

Only one of the main Open Stack projects uses Django - and it is a complete pain to work on as a result.

Most of the projects in OpenStack use Flask or Pecan - or Falcon for one or two of the more performance sensitive APIs

[gejjaxxita]

Having used Django and that project (Horizon) extensively, I think that Horizon is not a pain to work on as a result of Django, it was just badly written.