Update to Drupal 8.0.0 beta 14. For more information, see https://drupal.org/node/2544542

core/modules/search/migration_templates/d6_search_page.yml

@@ -0,0 +1,25 @@
+id: d6_search_page
+label: Drupal 6 search page configuration
+migration_tags:
+  - Drupal 6
+source:
+  plugin: variable
+  variables:
+    - node_rank_comments
+    - node_rank_promote
+    - node_rank_recent
+    - node_rank_relevance
+    - node_rank_sticky
+    - node_rank_views
+  constants:
+    id: node_search
+    path: node
+    plugin: node_search
+process:
+  id: 'constants/id'
+  path: 'constants/path'
+  plugin: 'constants/plugin'
+  'configuration/rankings':
+    plugin: d6_search_configuration_rankings
+destination:
+  plugin: entity:search_page

core/modules/search/migration_templates/d6_search_settings.yml

@@ -0,0 +1,22 @@
+id: d6_search_settings
+label: Drupal 6 search configuration
+migration_tags:
+  - Drupal 6
+source:
+  plugin: variable
+  constants:
+    status: true
+  variables:
+    - minimum_word_size
+    - overlap_cjk
+    - search_cron_limit
+    - search_tag_weights
+    - search_and_or_limit
+process:
+  'index/minimum_word_size': minimum_word_size
+  'index/overlap_cjk': overlap_cjk
+  'index/cron_limit': search_cron_limit
+  logging: 'constants/status'
+destination:
+  plugin: config
+  config_name: search.settings