### Summary Opening Admin Settings page results in the error 500 if ElasticSearch hostname contains `localhost`, and it is not accessible on the server. ### Steps to reproduce - have a GitLab instance without properly configured loopback/localhost address (you may emulate it by adding a fake `<IP> localhost` record to `/etc/hosts` file) - have default ElasticSearch settings on your GitLab server: URL set to `http://localhost:9200`, `Elasticsearch indexing` & `Search with Elasticsearch enabled` unchecked - try to open Admin Area > Settings ### What is the current *bug* behavior? Error 500 will be shown in UI, see the log below ### What is the expected *correct* behavior? There should be no error in UI ### Relevant logs and/or screenshots ```text ==> /var/log/gitlab/gitlab-rails/production.log <== Started GET "/admin/application_settings/general" for 10.21.255.20 at 2021-01-26 03:05:53 +0000 Processing by Admin::ApplicationSettingsController#general as HTML Completed 500 Internal Server Error in 475ms (ActiveRecord: 53.5ms | Elasticsearch: 0.0ms | Allocations: 420907) ActionView::Template::Error (Network is unreachable - Network is unreachable - connect(2) for "localhost" port 9200 (localhost:9200)): 4: - recreate_index_link_start = '<a href="%{url}" target="_blank" rel="noopener noreferrer">'.html_safe % { url: recreate_index_url } 5: - recreate_index_text = _("Changes won't take place until the index is %{link_start}recreated%{link_end}.").html_safe % { link_start: recreate_index_link_start, link_end: '</a>'.html_safe } 6: - expanded = integration_expanded?('elasticsearch_') 7: - elasticsearch_available = Gitlab::Elastic::Helper.default.client.ping 8: 9: %section.settings.as-elasticsearch.no-animate#js-elasticsearch-settings{ class: ('expanded' if expanded), data: { qa_selector: 'elasticsearch_tab' } } 10: .settings-header lib/gitlab/instrumentation/elasticsearch_transport.rb:12:in `perform_request' ee/app/views/admin/application_settings/_elasticsearch_form.html.haml:7 app/helpers/application_helper.rb:17:in `render_if_exists' app/views/admin/application_settings/general.html.haml:107 app/controllers/application_controller.rb:125:in `render' ee/lib/gitlab/ip_address_state.rb:10:in `with' ee/app/controllers/ee/application_controller.rb:44:in `set_current_ip_address' app/controllers/application_controller.rb:482:in `set_current_admin' lib/gitlab/session.rb:11:in `with_session' app/controllers/application_controller.rb:473:in `set_session_storage' lib/gitlab/i18n.rb:73:in `with_locale' lib/gitlab/i18n.rb:79:in `with_user_locale' app/controllers/application_controller.rb:467:in `set_locale' lib/gitlab/error_tracking.rb:52:in `with_context' app/controllers/application_controller.rb:532:in `sentry_context' app/controllers/application_controller.rb:460:in `block in set_current_context' lib/gitlab/application_context.rb:56:in `block in use' lib/gitlab/application_context.rb:56:in `use' lib/gitlab/application_context.rb:22:in `with_context' app/controllers/application_controller.rb:451:in `set_current_context' lib/gitlab/metrics/elasticsearch_rack_middleware.rb:16:in `call' lib/gitlab/middleware/rails_queue_duration.rb:33:in `call' lib/gitlab/metrics/rack_middleware.rb:16:in `block in call' lib/gitlab/metrics/transaction.rb:56:in `run' lib/gitlab/metrics/rack_middleware.rb:16:in `call' lib/gitlab/request_profiler/middleware.rb:17:in `call' lib/gitlab/jira/middleware.rb:19:in `call' lib/gitlab/middleware/go.rb:20:in `call' lib/gitlab/etag_caching/middleware.rb:21:in `call' lib/gitlab/middleware/multipart.rb:172:in `call' lib/gitlab/middleware/read_only/controller.rb:50:in `call' lib/gitlab/middleware/read_only.rb:18:in `call' lib/gitlab/middleware/same_site_cookies.rb:27:in `call' lib/gitlab/middleware/handle_malformed_strings.rb:21:in `call' lib/gitlab/middleware/basic_health_check.rb:25:in `call' lib/gitlab/middleware/handle_ip_spoof_attack_error.rb:25:in `call' lib/gitlab/middleware/request_context.rb:23:in `call' config/initializers/fix_local_cache_middleware.rb:9:in `call' lib/gitlab/metrics/requests_rack_middleware.rb:76:in `call' lib/gitlab/middleware/release_env.rb:12:in `call' ``` Another possible error message: ```text ActionView::Template::Error (No route to host - No route to host - connect(2) for "localhost" port 9200 (localhost:9200)): ``` ### Output of checks #### Results of GitLab environment info <!-- Input any relevant GitLab environment information if needed. --> <details> <summary>Expand for output related to GitLab environment info</summary> <pre> System information System: Ubuntu 18.04 Proxy: no Current User: git Using RVM: no Ruby Version: 2.7.2p137 Gem Version: 3.1.4 Bundler Version:2.1.4 Rake Version: 13.0.3 Redis Version: 5.0.9 Git Version: 2.29.0 Sidekiq Version:5.2.9 Go Version: unknown GitLab information Version: 13.8.0-ee Revision: 1ae10d09692 Directory: /opt/gitlab/embedded/service/gitlab-rails DB Adapter: PostgreSQL DB Version: 12.4 URL: https://domain.tld HTTP Clone URL: https://domain.tld/some-group/some-project.git SSH Clone URL: git@domain.tld:some-group/some-project.git Elasticsearch: no Geo: no Using LDAP: no Using Omniauth: yes Omniauth Providers: GitLab Shell Version: 13.15.0 Repository storage paths: - default: /var/opt/gitlab/git-data/repositories GitLab Shell path: /opt/gitlab/embedded/service/gitlab-shell Git: /opt/gitlab/embedded/bin/git </pre> </details> #### Results of GitLab application Check <!-- Input any relevant GitLab application check information if needed. --> <details> <summary>Expand for output related to the GitLab application check</summary> <pre> Checking GitLab subtasks ... Checking GitLab Shell ... GitLab Shell: ... GitLab Shell version >= 13.15.0 ? ... OK (13.15.0) Running /opt/gitlab/embedded/service/gitlab-shell/bin/check Internal API available: OK Redis available via internal API: OK gitlab-shell self-check successful Checking GitLab Shell ... Finished Checking Gitaly ... Gitaly: ... default ... OK Checking Gitaly ... Finished Checking Sidekiq ... Sidekiq: ... Running? ... yes Number of Sidekiq processes ... 1 Checking Sidekiq ... Finished Checking Incoming Email ... Incoming Email: ... Reply by email is disabled in config/gitlab.yml Checking Incoming Email ... Finished Checking LDAP ... LDAP: ... LDAP is disabled in config/gitlab.yml Checking LDAP ... Finished Checking GitLab App ... Git configured correctly? ... yes Database config exists? ... yes All migrations up? ... yes Database contains orphaned GroupMembers? ... no GitLab config exists? ... yes GitLab config up to date? ... yes Log directory writable? ... yes Tmp directory writable? ... yes Uploads directory exists? ... yes Uploads directory has correct permissions? ... yes Uploads directory tmp has correct permissions? ... yes Init script exists? ... skipped (omnibus-gitlab has no init script) Init script up-to-date? ... skipped (omnibus-gitlab has no init script) Projects have namespace: ... ... Redis version >= 4.0.0? ... yes Ruby version >= 2.7.2 ? ... yes (2.7.2) Git version >= 2.29.0 ? ... yes (2.29.0) Git user has default SSH configuration? ... yes Active users: ... 37 Is authorized keys file accessible? ... yes GitLab configured to store new projects in hashed storage? ... yes All projects are in hashed storage? ... yes Elasticsearch version 7.x (6.4 - 6.x deprecated to be removed in 13.8)? ... skipped (elasticsearch is disabled) Checking GitLab App ... Finished Checking GitLab subtasks ... Finished </pre> </details> ### Details - Seems that the issue was introduced in the MR https://gitlab.com/gitlab-org/gitlab/-/merge_requests/51335, see the comment https://gitlab.com/gitlab-org/gitlab/-/merge_requests/51335#note_493819122 for details - When one tries to open Admin Area > Settings page, there is an attempt to run `Gitlab::Elastic::Helper.default.client.ping` even when ElasticSearch is not enabled, and the error is shown in UI if this request fails.