When I take a VMware VM and attempt to rebuild it by hitting the build button the UI appears to hang: https://www.evernote.com/l/APddCSYEeqlK9LWiE28lXbNpX2MJ_BXFLig

It appears to have an issue with retrieving power status:

018-04-24T12:33:04 ea2faca8 [app] [I]   Rendered hosts/review_before_build.html.erb (38.8ms)
2018-04-24T12:33:04 ea2faca8 [app] [W] Action failed
 | ActionView::Template::Error: uninitialized constant Fog::Compute::Ovirt
 | /usr/share/foreman/app/services/power_manager/virt.rb:35:in `default_action'
 | /usr/share/foreman/app/services/power_manager/base.rb:25:in `block (2 levels) in <class:Base>'
 | /usr/share/foreman/app/models/concerns/hostext/power_interface.rb:22:in `supports_power_and_running?'
 | /usr/share/foreman/app/views/hosts/review_before_build.html.erb:27:in `block in _8de6f7cd1a0a8decfc092ad8f7d483d1'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/helpers/capture_helper.rb:39:in `block in capture'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/helpers/capture_helper.rb:203:in `with_output_buffer'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/helpers/capture_helper.rb:39:in `capture'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/helpers/form_helper.rb:450:in `form_for'
 | /usr/share/foreman/app/helpers/form_helper.rb:296:in `form_for'
 | /usr/share/foreman/app/views/hosts/review_before_build.html.erb:22:in `_8de6f7cd1a0a8decfc092ad8f7d483d1'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/template.rb:157:in `block in render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/notifications.rb:168:in `instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/template.rb:352:in `instrument_render_template'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/template.rb:155:in `render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/deface-1.2.0/lib/deface/action_view_extensions.rb:41:in `render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/template_renderer.rb:52:in `block (2 levels) in render_template'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/abstract_renderer.rb:42:in `block in instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/notifications.rb:166:in `block in instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/notifications.rb:166:in `instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/abstract_renderer.rb:41:in `instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/template_renderer.rb:51:in `block in render_template'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/template_renderer.rb:59:in `render_with_layout'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/template_renderer.rb:50:in `render_template'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/template_renderer.rb:14:in `render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/renderer.rb:42:in `render_template'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/renderer/renderer.rb:23:in `render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/rendering.rb:103:in `_render_template'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/streaming.rb:217:in `_render_template'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/rendering.rb:83:in `render_to_body'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/rendering.rb:52:in `render_to_body'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/renderers.rb:141:in `render_to_body'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/abstract_controller/rendering.rb:24:in `render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/rendering.rb:36:in `render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/instrumentation.rb:44:in `block (2 levels) in render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/core_ext/benchmark.rb:12:in `block in ms'
 | /usr/lib/ruby/2.3.0/benchmark.rb:308:in `realtime'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/core_ext/benchmark.rb:12:in `ms'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/instrumentation.rb:44:in `block in render'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/instrumentation.rb:87:in `cleanup_view_runtime'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activerecord-5.1.4/lib/active_record/railties/controller_runtime.rb:29:in `cleanup_view_runtime'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/instrumentation.rb:43:in `render'
 | /usr/share/foreman/app/controllers/hosts_controller.rb:227:in `review_before_build'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/basic_implicit_render.rb:4:in `send_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/abstract_controller/base.rb:186:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/rendering.rb:30:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/abstract_controller/callbacks.rb:20:in `block in process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:108:in `block in run_callbacks'
 | /usr/share/foreman/app/controllers/concerns/application_shared.rb:15:in `set_timezone'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /usr/share/foreman/app/models/concerns/foreman/thread_session.rb:32:in `clear_thread'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /usr/share/foreman/app/controllers/concerns/foreman/controller/topbar_sweeper.rb:12:in `set_topbar_sweeper_controller'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/audited-4.5.0/lib/audited/sweeper.rb:14:in `around'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/audited-4.5.0/lib/audited/sweeper.rb:14:in `around'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:117:in `block in run_callbacks'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:135:in `run_callbacks'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/abstract_controller/callbacks.rb:19:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/rescue.rb:20:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/notifications.rb:166:in `block in instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/notifications/instrumenter.rb:21:in `instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/notifications.rb:166:in `instrument'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/instrumentation.rb:30:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal/params_wrapper.rb:252:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activerecord-5.1.4/lib/active_record/railties/controller_runtime.rb:22:in `process_action'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/abstract_controller/base.rb:124:in `process'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionview-5.1.4/lib/action_view/rendering.rb:30:in `process'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal.rb:189:in `dispatch'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_controller/metal.rb:253:in `dispatch'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/routing/route_set.rb:49:in `dispatch'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/routing/route_set.rb:31:in `serve'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/journey/router.rb:50:in `block in serve'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/journey/router.rb:33:in `each'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/journey/router.rb:33:in `serve'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/routing/route_set.rb:834:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/apipie-rails-0.5.7/lib/apipie/static_dispatcher.rb:65:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/apipie-rails-0.5.7/lib/apipie/extractor/recorder.rb:136:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/apipie-rails-0.5.7/lib/apipie/middleware/checksum_in_headers.rb:27:in `call'
 | /usr/share/foreman/lib/middleware/catch_json_parse_errors.rb:8:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/etag.rb:25:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/conditional_get.rb:25:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/head.rb:12:in `call'
 | /usr/share/foreman/lib/middleware/session_safe_logging.rb:17:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/session/abstract/id.rb:232:in `context'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/session/abstract/id.rb:226:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/cookies.rb:613:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/callbacks.rb:26:in `block in call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/callbacks.rb:97:in `run_callbacks'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/callbacks.rb:24:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/debug_exceptions.rb:59:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/show_exceptions.rb:31:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/railties-5.1.4/lib/rails/rack/logger.rb:36:in `call_app'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/railties-5.1.4/lib/rails/rack/logger.rb:26:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/sprockets-rails-3.2.1/lib/sprockets/rails/quiet_assets.rb:13:in `call'
 | /usr/share/foreman/lib/middleware/tagged_logging.rb:18:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/remote_ip.rb:79:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/request_id.rb:25:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/method_override.rb:22:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/runtime.rb:22:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/activesupport-5.1.4/lib/active_support/cache/strategy/local_cache_middleware.rb:27:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/executor.rb:12:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/actionpack-5.1.4/lib/action_dispatch/middleware/static.rb:125:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/sendfile.rb:111:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/secure_headers-3.7.3/lib/secure_headers/middleware.rb:12:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/railties-5.1.4/lib/rails/engine.rb:522:in `call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/railties-5.1.4/lib/rails/railtie.rb:185:in `public_send'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/railties-5.1.4/lib/rails/railtie.rb:185:in `method_missing'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/urlmap.rb:68:in `block in call'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/urlmap.rb:53:in `each'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/rack-2.0.4/lib/rack/urlmap.rb:53:in `call'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/rack/thread_handler_extension.rb:97:in `process_request'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler/thread_handler.rb:152:in `accept_and_process_next_request'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler/thread_handler.rb:113:in `main_loop'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/request_handler.rb:416:in `block (3 levels) in start_threads'
 | /usr/lib/ruby/vendor_ruby/phusion_passenger/utils.rb:113:in `block in create_thread_and_abort_on_exception'
 | /usr/share/foreman/vendor/ruby/2.3.0/gems/logging-2.2.2/lib/logging/diagnostic_context.rb:474:in `block in create_with_logging_context'
2018-04-24T12:33:04 ea2faca8 [app] [I]   Rendering common/500.html.erb
2018-04-24T12:33:04 ea2faca8 [app] [I]   Rendered common/500.html.erb (3.5ms)
2018-04-24T12:33:04 ea2faca8 [app] [I] Completed 500 Internal Server Error in 2959ms (Views: 6.1ms | ActiveRecord: 162.4ms)

Notice the error is with ovirt, and my VMs are VMWare. As another data point, power status and functionality works inside the Computer Resource/Virtual Machine tab.

More then willing to help debug this!!