Comment 0 for bug 1788180

Setup description
------------------
Multinode deployment with kolla with keepalived and haproxy with SSL termination.
nova-serialproxy is configured with base_url=wss:// because I want my users to
connect through a secure channel.

Problem description
-------------------
Get a serial-proxy url with token like this (works fine):
  openstack console url show --insecure --serial <uuid>

Connect to the url (in my case: simple python websocket):
  python serial.py wss://hostname:6083?token=<token>

Result:
  nova-serialproxy closes the connection
  Log contains "Origin header protocol does not match this host."

Expected result:
  connection works

Problem analysis
----------------
haproxy accepts the wss:// connection and forwards the connection to the
serialproxy process. HAproxy changes the Origin header to 'http' and adds
a header 'X-Forwarded-Proto: https'.

'websocketproxy.py' accepts the connection and fails because the URL in 'Origin'
has not the same scheme/protocol as issued in the 'console url show' command.

AFAIK the behaviour of haproxy is ok and the serialproxy should offer a possiblity to
check the value of 'X-Forwarded-Proto' as source protocol.