Correctly migrate system indices that are still using named types (#8…

…3817) Prior to this PR, the system index migration facility did not use the index type configured in the descriptor, instead always using `_doc`. This PR adjusts the migration facility to use the index type specified in the descriptor instead. Note that this PR is only targeted at 7.17, as it is the only version impacted.
elastic · Feb 17, 2022 · c3f34f6 · c3f34f6
1 parent f8e5598
commit c3f34f6
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Showing 4 changed files with 28 additions and 3 deletions.
diff --git a/docs/changelog/83817.yaml b/docs/changelog/83817.yaml
@@ -0,0 +1,6 @@
+pr: 83817
+summary: Correctly migrate system indices that are still using named types
+area: Infra/Core
+type: bug
+issues:
+ - 83779
diff --git a/.../reindex/src/internalClusterTest/java/org/elasticsearch/migration/FeatureMigrationIT.java b/.../reindex/src/internalClusterTest/java/org/elasticsearch/migration/FeatureMigrationIT.java
@@ -356,12 +356,13 @@ public void createSystemIndexForDescriptor(SystemIndexDescriptor descriptor) thr
         .setPrimaryIndex(".int-man-old")
         .setType(SystemIndexDescriptor.Type.INTERNAL_MANAGED)
         .setSettings(createSimpleSettings(NEEDS_UPGRADE_VERSION, INTERNAL_MANAGED_FLAG_VALUE))
-        .setMappings(createSimpleMapping(true, true, true))
+        .setMappings(createSimpleMapping(true, true, false)) // See note below
         .setOrigin(ORIGIN)
         .setVersionMetaKey(VERSION_META_KEY)
         .setAllowedElasticProductOrigins(Collections.emptyList())
         .setMinimumNodeVersion(NEEDS_UPGRADE_VERSION)
         .setPriorSystemIndexDescriptors(Collections.emptyList())
+        .setIndexType("doc") // This simulates `.tasks`, which uses a nonstandard type name. EXTERNAL_MANAGED tests the default type.
         .build();
     static final SystemIndexDescriptor INTERNAL_UNMANAGED = SystemIndexDescriptor.builder()
         .setIndexPattern(".int-unman-*")

diff --git a/server/src/main/java/org/elasticsearch/upgrades/SystemIndexMigrationInfo.java b/server/src/main/java/org/elasticsearch/upgrades/SystemIndexMigrationInfo.java
@@ -47,6 +47,7 @@ class SystemIndexMigrationInfo implements Comparable<SystemIndexMigrationInfo> {
     private final Settings settings;
     private final String mapping;
     private final String origin;
+    private final String indexType;
     private final SystemIndices.Feature owningFeature;
 
     private static final Comparator<SystemIndexMigrationInfo> SAME_CLASS_COMPARATOR = Comparator.comparing(
@@ -59,13 +60,15 @@ private SystemIndexMigrationInfo(
         Settings settings,
         String mapping,
         String origin,
+        String indexType,
         SystemIndices.Feature owningFeature
     ) {
         this.currentIndex = currentIndex;
         this.featureName = featureName;
         this.settings = settings;
         this.mapping = mapping;
         this.origin = origin;
+        this.indexType = indexType;
         this.owningFeature = owningFeature;
     }
 
@@ -118,6 +121,13 @@ String getOrigin() {
         return origin;
     }
 
+    /**
+     * Gets the type that should be used for the mapping of this index
+     */
+    String getIndexType() {
+        return indexType;
+    }
+
     /**
      * Invokes the pre-migration hook for the feature that owns this index.
      * See {@link SystemIndexPlugin#prepareForIndicesMigration(ClusterService, Client, ActionListener)}.
@@ -220,7 +230,15 @@ static SystemIndexMigrationInfo build(
             }
         }
 
-        return new SystemIndexMigrationInfo(currentIndex, feature.getName(), settings, mapping, descriptor.getOrigin(), feature);
+        return new SystemIndexMigrationInfo(
+            currentIndex,
+            feature.getName(),
+            settings,
+            mapping,
+            descriptor.getOrigin(),
+            descriptor.getIndexType(),
+            feature
+        );
     }
 
     private static Settings copySettingsForNewIndex(Settings currentIndexSettings, IndexScopedSettings indexScopedSettings) {

diff --git a/server/src/main/java/org/elasticsearch/upgrades/SystemIndexMigrator.java b/server/src/main/java/org/elasticsearch/upgrades/SystemIndexMigrator.java
@@ -468,7 +468,7 @@ private void createIndex(SystemIndexMigrationInfo migrationInfo, ActionListener<
             settingsBuilder.remove("index.blocks.metadata");
         }
         createRequest.waitForActiveShards(ActiveShardCount.ALL)
-            .mappings(Collections.singletonMap("_doc", migrationInfo.getMappings()))
+            .mappings(Collections.singletonMap(migrationInfo.getIndexType(), migrationInfo.getMappings()))
             .settings(migrationInfo.getSettings() == null ? Settings.EMPTY : settingsBuilder.build());
         metadataCreateIndexService.createIndex(createRequest, listener);
     }