Added extra checks for secondary nodes

lib/system_check/geo/database_replication_check.rb

+module SystemCheck
+  module Geo
+    class DatabaseReplicationCheck < SystemCheck::BaseCheck
+      set_name 'Using database streaming replication?'
+      set_skip_reason 'not a secondary node'
+
+      def skip?
+        !Gitlab::Geo.secondary?
+      end
+
+      def check?
+        ActiveRecord::Base.connection.execute('SELECT pg_is_in_recovery()').first.fetch('pg_is_in_recovery') == 't'
+      end
+
+      def show_error
+        try_fixing_it(
+          'Follow Geo setup instructions to configure primary and secondary nodes for streaming replication'
+        )
+
+        for_more_information('doc/gitlab-geo/database.md')
+      end
+    end
+  end
+end

lib/system_check/geo/geo_database_configured_check.rb

+module SystemCheck
+  module Geo
+    class GeoDatabaseConfiguredCheck < SystemCheck::BaseCheck
+      set_name 'GitLab Geo secondary database is correctly configured'
+      set_skip_reason 'not a secondary node'
+
+      def skip?
+        !Gitlab::Geo.secondary?
+      end
+
+      def check?
+        Gitlab::Geo.geo_database_configured?
+      end
+
+      def show_error
+        try_fixing_it(
+          'Check if you enabled the `geo_secondary_role` or `geo_postgresql` in the gitlab.rb config file.'
+        )
+
+        for_more_information('doc/gitlab-geo/database.md')
+      end
+    end
+  end
+end

lib/tasks/gitlab/check.rake

@@ -549,6 +549,8 @@ namespace :gitlab do
       checks = [
         SystemCheck::Geo::LicenseCheck,
         SystemCheck::Geo::EnabledCheck,
+        SystemCheck::Geo::GeoDatabaseConfiguredCheck,
+        SystemCheck::Geo::DatabaseReplicationCheck,
         SystemCheck::Geo::HttpConnectionCheck
       ]