The default value for OFFLINE_COMPRESS is False, as per the Django
compressor docs. When using offline compression, it seems that different
request contexts may generate different CSS files with different names
by way of the SCSS generator. When the HTML is returned to the browser,
the CSS filename referenced will only exist on the node that received
the initial request and generated the CSS file locally, however in a
load-balanced scenario with multiple Horizon instances, the actual HTTP
request for the CSS file has a n-1/n chance of hitting another node that
may be lacking that file, resulting in an unstyled page.
Changing the OFFLINE_COMPRESS value to True enables Django to use the
pre-generated list of resources -- created via the manage.py compress
command -- which is stored in a manifest.json file and should be the
same name/content across the instances since it's not varying by request
context like during online compression.
Change-Id: Iccb9b8cd30b7a61435f9ccc813c4032a24cbe52a
Closes-Bug: #1423783
21f9175fb0