put virtualenv activation during build in comment. That means that for the moment the build machine must be provisionned beforehand, or ansible must be available globally
FastCGIExternalServer <%= @faux_path %> -idle-timeout <%= @timeout %> <%= if @flush then '-flush' end %> -host <%= @host %>
Alias <%= @fcgi_alias %> <%= @faux_path %>
Action <%= @file_type %> <%= @fcgi_alias %>