During installation, the finish script gets a "304 Not Modified" from the director. Which is true because Foreman has already created the host. However, this leads to an error and the installation can not be completed:
E, [2018-02-02T15:35:26.518563 4f8568d9] ERROR -- : Error connecting to Icinga Director at https://icinga.test.local/director/host?name=test02-fra0.test.local: 304 Not Modified
D, [2018-02-02T15:35:26.518610 4f8568d9] DEBUG -- : Error connecting to Icinga Director at https://icinga.test.local/director/host?name=test02-fra0.test.local: 304 Not Modified (Proxy::Monitoring::Error)
/usr/lib/ruby/vendor_ruby/smart_proxy_monitoring_icingadirector/director_client.rb:41:in `rescue in put'
/usr/lib/ruby/vendor_ruby/smart_proxy_monitoring_icingadirector/director_client.rb:38:in `put'
/usr/lib/ruby/vendor_ruby/smart_proxy_monitoring_icingadirector/monitoring_icingadirector_main.rb:21:in `update_host'
/usr/lib/ruby/vendor_ruby/smart_proxy_monitoring/monitoring_api.rb:42:in `block (2 levels) in <class:Api>'
/usr/lib/ruby/vendor_ruby/smart_proxy_monitoring/monitoring_api.rb:83:in `log_provider_errors'
/usr/lib/ruby/vendor_ruby/smart_proxy_monitoring/monitoring_api.rb:36:in `block in <class:Api>'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1610:in `call'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1610:in `block in compile!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:975:in `block (3 levels) in route!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:994:in `route_eval'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:975:in `block (2 levels) in route!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1015:in `block in process_route'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1013:in `catch'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1013:in `process_route'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:973:in `block in route!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:972:in `each'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:972:in `route!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1085:in `block in dispatch!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1067:in `block in invoke'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1067:in `catch'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1067:in `invoke'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1082:in `dispatch!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:907:in `block in call!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1067:in `block in invoke'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1067:in `catch'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1067:in `invoke'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:907:in `call!'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:895:in `call'
/usr/lib/ruby/vendor_ruby/rack/commonlogger.rb:33:in `call'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:219:in `call'
/usr/share/foreman-proxy/lib/proxy/log.rb:109:in `call'
/usr/share/foreman-proxy/lib/proxy/request_id_middleware.rb:9:in `call'
/usr/lib/ruby/vendor_ruby/rack/protection/xss_header.rb:18:in `call'
/usr/lib/ruby/vendor_ruby/rack/protection/path_traversal.rb:16:in `call'
/usr/lib/ruby/vendor_ruby/rack/protection/json_csrf.rb:18:in `call'
/usr/lib/ruby/vendor_ruby/rack/protection/base.rb:49:in `call'
/usr/lib/ruby/vendor_ruby/rack/protection/base.rb:49:in `call'
/usr/lib/ruby/vendor_ruby/rack/protection/frame_options.rb:31:in `call'
/usr/lib/ruby/vendor_ruby/rack/nulllogger.rb:9:in `call'
/usr/lib/ruby/vendor_ruby/rack/head.rb:13:in `call'
/usr/lib/ruby/vendor_ruby/sinatra/show_exceptions.rb:25:in `call'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:182:in `call'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:2013:in `call'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1487:in `block in call'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1787:in `synchronize'
/usr/lib/ruby/vendor_ruby/sinatra/base.rb:1487:in `call'
/usr/lib/ruby/vendor_ruby/rack/urlmap.rb:66:in `block in call'
/usr/lib/ruby/vendor_ruby/rack/urlmap.rb:50:in `each'
/usr/lib/ruby/vendor_ruby/rack/urlmap.rb:50:in `call'
/usr/lib/ruby/vendor_ruby/rack/builder.rb:153:in `call'
/usr/lib/ruby/vendor_ruby/rack/handler/webrick.rb:88:in `service'
/usr/lib/ruby/2.3.0/webrick/httpserver.rb:140:in `service'
/usr/lib/ruby/2.3.0/webrick/httpserver.rb:96:in `run'
/usr/lib/ruby/2.3.0/webrick/server.rb:296:in `block in start_thread'
During installation, the finish script gets a "304 Not Modified" from the director. Which is true because Foreman has already created the host. However, this leads to an error and the installation can not be completed: