Horizon has, since OSA's inception, been deployed with HTTPS
access enabled, and has had no way to turn it off. Some use-cases
may want to access via HTTP instead, so this patch enables
the following:
1. Listen via HTTPS on a load balancer, but via HTTP on the
horizon host and have the load balancer forward the correct
headers. It will do this by default in the integrated build
due to the presence of the load balancer, so the current
behaviour is retained.
2. Enable HTTPS on the horizon host without a load balancer.
This is the role's default behaviour which matches what it
always has been.
3. Disable HTTPS entirely by setting ``haproxy_ssl: no`` (which
will also disable https on haproxy. This setting is inherited
by the new ``horizon_enable_ssl`` variable by default. This
is a new option.
Co-Authored-By: Jesse Pretorius <jesse.pretorius@rackspace.co.uk>
Change-Id: I823f2f949258157e306dbf80570abe53373da0c3
Closes-Bug: 1794337
4283200534