Malformed request url (HTTP 400)

If you get e.g.

  ERROR: Malformed request url (HTTP 400) (Request-ID: req-b83b862f-6aed-4420-8849-6dcf7c2fe9ae)

as a response to Nova API, consider the following:

 1) If you think you're using keystone, make sure that

         auth_strategy = keystone

      is set in nova.conf

 2) Check that the tenant ID in the request matches the tenant you are authenticated under

See also bug #915151