Add support for restoring from snapshot with search replicas (#16111)

CHANGELOG.md

@@ -29,6 +29,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - [Star Tree - Search] Add support for metric aggregations with/without term query ([15289](https://github.com/opensearch-project/OpenSearch/pull/15289))
 - URI path filtering support in cluster stats API ([#15938](https://github.com/opensearch-project/OpenSearch/pull/15938))
 - Add support for renaming aliases during snapshot restore ([#16292](https://github.com/opensearch-project/OpenSearch/pull/16292))
+- Add support for restoring from snapshot with search replicas ([#16111](https://github.com/opensearch-project/OpenSearch/pull/16111))
 
 ### Dependencies
 - Bump `org.apache.logging.log4j:log4j-core` from 2.23.1 to 2.24.0 ([#15858](https://github.com/opensearch-project/OpenSearch/pull/15858))

server/src/internalClusterTest/java/org/opensearch/indices/replication/SearchReplicaRestoreIT.java

@@ -0,0 +1,226 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.indices.replication;
+
+import org.opensearch.action.search.SearchResponse;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.common.util.FeatureFlags;
+import org.opensearch.index.query.QueryBuilders;
+import org.opensearch.indices.replication.common.ReplicationType;
+import org.opensearch.snapshots.AbstractSnapshotIntegTestCase;
+import org.opensearch.snapshots.SnapshotRestoreException;
+import org.opensearch.test.OpenSearchIntegTestCase;
+
+import java.util.List;
+
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SEARCH_REPLICAS;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertAcked;
+import static org.opensearch.test.hamcrest.OpenSearchAssertions.assertHitCount;
+
+@OpenSearchIntegTestCase.ClusterScope(scope = OpenSearchIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class SearchReplicaRestoreIT extends AbstractSnapshotIntegTestCase {
+
+    private static final String INDEX_NAME = "test-idx-1";
+    private static final String RESTORED_INDEX_NAME = INDEX_NAME + "-restored";
+    private static final String REPOSITORY_NAME = "test-repo";
+    private static final String SNAPSHOT_NAME = "test-snapshot";
+    private static final String FS_REPOSITORY_TYPE = "fs";
+    private static final int DOC_COUNT = 10;
+
+    @Override
+    protected Settings featureFlagSettings() {
+        return Settings.builder().put(super.featureFlagSettings()).put(FeatureFlags.READER_WRITER_SPLIT_EXPERIMENTAL, true).build();
+    }
+
+    public void testSearchReplicaRestore_WhenSnapshotOnDocRep_RestoreOnDocRepWithSearchReplica() throws Exception {
+        bootstrapIndexWithOutSearchReplicas(ReplicationType.DOCUMENT);
+        createRepoAndSnapshot(REPOSITORY_NAME, FS_REPOSITORY_TYPE, SNAPSHOT_NAME, INDEX_NAME);
+
+        SnapshotRestoreException exception = expectThrows(
+            SnapshotRestoreException.class,
+            () -> restoreSnapshot(
+                REPOSITORY_NAME,
+                SNAPSHOT_NAME,
+                INDEX_NAME,
+                RESTORED_INDEX_NAME,
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT)
+                    .put(SETTING_NUMBER_OF_SEARCH_REPLICAS, 1)
+                    .build()
+            )
+        );
+        assertTrue(exception.getMessage().contains(getSnapshotExceptionMessage(ReplicationType.DOCUMENT, ReplicationType.DOCUMENT)));
+    }
+
+    public void testSearchReplicaRestore_WhenSnapshotOnDocRep_RestoreOnSegRepWithSearchReplica() throws Exception {
+        bootstrapIndexWithOutSearchReplicas(ReplicationType.DOCUMENT);
+        createRepoAndSnapshot(REPOSITORY_NAME, FS_REPOSITORY_TYPE, SNAPSHOT_NAME, INDEX_NAME);
+
+        restoreSnapshot(
+            REPOSITORY_NAME,
+            SNAPSHOT_NAME,
+            INDEX_NAME,
+            RESTORED_INDEX_NAME,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+                .put(SETTING_NUMBER_OF_SEARCH_REPLICAS, 1)
+                .build()
+        );
+        ensureYellowAndNoInitializingShards(RESTORED_INDEX_NAME);
+        internalCluster().startDataOnlyNode();
+        ensureGreen(RESTORED_INDEX_NAME);
+        assertEquals(1, getNumberOfSearchReplicas(RESTORED_INDEX_NAME));
+
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, DOC_COUNT);
+    }
+
+    public void testSearchReplicaRestore_WhenSnapshotOnSegRep_RestoreOnDocRepWithSearchReplica() throws Exception {
+        bootstrapIndexWithOutSearchReplicas(ReplicationType.SEGMENT);
+        createRepoAndSnapshot(REPOSITORY_NAME, FS_REPOSITORY_TYPE, SNAPSHOT_NAME, INDEX_NAME);
+
+        SnapshotRestoreException exception = expectThrows(
+            SnapshotRestoreException.class,
+            () -> restoreSnapshot(
+                REPOSITORY_NAME,
+                SNAPSHOT_NAME,
+                INDEX_NAME,
+                RESTORED_INDEX_NAME,
+                Settings.builder()
+                    .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT)
+                    .put(SETTING_NUMBER_OF_SEARCH_REPLICAS, 1)
+                    .build()
+            )
+        );
+        assertTrue(exception.getMessage().contains(getSnapshotExceptionMessage(ReplicationType.SEGMENT, ReplicationType.DOCUMENT)));
+    }
+
+    public void testSearchReplicaRestore_WhenSnapshotOnSegRep_RestoreOnSegRepWithSearchReplica() throws Exception {
+        bootstrapIndexWithOutSearchReplicas(ReplicationType.SEGMENT);
+        createRepoAndSnapshot(REPOSITORY_NAME, FS_REPOSITORY_TYPE, SNAPSHOT_NAME, INDEX_NAME);
+
+        restoreSnapshot(
+            REPOSITORY_NAME,
+            SNAPSHOT_NAME,
+            INDEX_NAME,
+            RESTORED_INDEX_NAME,
+            Settings.builder().put(SETTING_NUMBER_OF_SEARCH_REPLICAS, 1).build()
+        );
+        ensureYellowAndNoInitializingShards(RESTORED_INDEX_NAME);
+        internalCluster().startDataOnlyNode();
+        ensureGreen(RESTORED_INDEX_NAME);
+        assertEquals(1, getNumberOfSearchReplicas(RESTORED_INDEX_NAME));
+
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, DOC_COUNT);
+    }
+
+    public void testSearchReplicaRestore_WhenSnapshotOnSegRepWithSearchReplica_RestoreOnDocRep() throws Exception {
+        bootstrapIndexWithSearchReplicas();
+        createRepoAndSnapshot(REPOSITORY_NAME, FS_REPOSITORY_TYPE, SNAPSHOT_NAME, INDEX_NAME);
+
+        SnapshotRestoreException exception = expectThrows(
+            SnapshotRestoreException.class,
+            () -> restoreSnapshot(
+                REPOSITORY_NAME,
+                SNAPSHOT_NAME,
+                INDEX_NAME,
+                RESTORED_INDEX_NAME,
+                Settings.builder().put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT).build()
+            )
+        );
+        assertTrue(exception.getMessage().contains(getSnapshotExceptionMessage(ReplicationType.SEGMENT, ReplicationType.DOCUMENT)));
+    }
+
+    public void testSearchReplicaRestore_WhenSnapshotOnSegRepWithSearchReplica_RestoreOnDocRepWithNoSearchReplica() throws Exception {
+        bootstrapIndexWithSearchReplicas();
+        createRepoAndSnapshot(REPOSITORY_NAME, FS_REPOSITORY_TYPE, SNAPSHOT_NAME, INDEX_NAME);
+
+        restoreSnapshot(
+            REPOSITORY_NAME,
+            SNAPSHOT_NAME,
+            INDEX_NAME,
+            RESTORED_INDEX_NAME,
+            Settings.builder()
+                .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.DOCUMENT)
+                .put(SETTING_NUMBER_OF_SEARCH_REPLICAS, 0)
+                .build()
+        );
+        ensureGreen(RESTORED_INDEX_NAME);
+        assertEquals(0, getNumberOfSearchReplicas(RESTORED_INDEX_NAME));
+
+        SearchResponse resp = client().prepareSearch(RESTORED_INDEX_NAME).setQuery(QueryBuilders.matchAllQuery()).get();
+        assertHitCount(resp, DOC_COUNT);
+    }
+
+    private void bootstrapIndexWithOutSearchReplicas(ReplicationType replicationType) throws InterruptedException {
+        startCluster(2);
+
+        Settings settings = Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+            .put(SETTING_NUMBER_OF_SEARCH_REPLICAS, 0)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, replicationType)
+            .build();
+
+        createIndex(INDEX_NAME, settings);
+        indexRandomDocs(INDEX_NAME, DOC_COUNT);
+        refresh(INDEX_NAME);
+        ensureGreen(INDEX_NAME);
+    }
+
+    private void bootstrapIndexWithSearchReplicas() throws InterruptedException {
+        startCluster(3);
+
+        Settings settings = Settings.builder()
+            .put(super.indexSettings())
+            .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
+            .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 1)
+            .put(SETTING_NUMBER_OF_SEARCH_REPLICAS, 1)
+            .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
+            .build();
+
+        createIndex(INDEX_NAME, settings);
+        ensureGreen(INDEX_NAME);
+        for (int i = 0; i < DOC_COUNT; i++) {
+            client().prepareIndex(INDEX_NAME).setId(String.valueOf(i)).setSource("foo", "bar").get();
+        }
+        flushAndRefresh(INDEX_NAME);
+    }
+
+    private void startCluster(int numOfNodes) {
+        internalCluster().startClusterManagerOnlyNode();
+        internalCluster().startDataOnlyNodes(numOfNodes);
+    }
+
+    private void createRepoAndSnapshot(String repositoryName, String repositoryType, String snapshotName, String indexName) {
+        createRepository(repositoryName, repositoryType, randomRepoPath().toAbsolutePath());
+        createSnapshot(repositoryName, snapshotName, List.of(indexName));
+        assertAcked(client().admin().indices().prepareDelete(INDEX_NAME));
+        assertFalse("index [" + INDEX_NAME + "] should have been deleted", indexExists(INDEX_NAME));
+    }
+
+    private String getSnapshotExceptionMessage(ReplicationType snapshotReplicationType, ReplicationType restoreReplicationType) {
+        return "snapshot was created with [index.replication.type] as ["
+            + snapshotReplicationType
+            + "]. "
+            + "To restore with [index.replication.type] as ["
+            + restoreReplicationType
+            + "], "
+            + "[index.number_of_search_only_replicas] must be set to [0]";
+    }
+
+    private int getNumberOfSearchReplicas(String index) {
+        Metadata metadata = client().admin().cluster().prepareState().get().getState().metadata();
+        return Integer.valueOf(metadata.index(index).getSettings().get(SETTING_NUMBER_OF_SEARCH_REPLICAS));
+    }
+}

server/src/main/java/org/opensearch/cluster/routing/IndexRoutingTable.java

@@ -572,6 +572,17 @@ private Builder initializeAsRestore(
                         );
                     }
                 }
+                for (int i = 0; i < indexMetadata.getNumberOfSearchOnlyReplicas(); i++) {
+                    indexShardRoutingBuilder.addShard(
+                        ShardRouting.newUnassigned(
+                            shardId,
+                            false,
+                            true,
+                            PeerRecoverySource.INSTANCE, // TODO: Update to remote store if enabled
+                            unassignedInfo
+                        )
+                    );
+                }
                 shards.put(shardNumber, indexShardRoutingBuilder.build());
             }
             return this;

server/src/main/java/org/opensearch/snapshots/RestoreService.java

@@ -93,6 +93,7 @@
 import org.opensearch.index.store.remote.filecache.FileCacheStats;
 import org.opensearch.indices.IndicesService;
 import org.opensearch.indices.ShardLimitValidator;
+import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.node.remotestore.RemoteStoreNodeAttribute;
 import org.opensearch.node.remotestore.RemoteStoreNodeService;
 import org.opensearch.repositories.IndexId;
@@ -121,10 +122,12 @@
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_HISTORY_UUID;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_INDEX_UUID;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_REPLICAS;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SEARCH_REPLICAS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_NUMBER_OF_SHARDS;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_SEGMENT_STORE_REPOSITORY;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_STORE_ENABLED;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY;
+import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_REPLICATION_TYPE;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_CREATED;
 import static org.opensearch.cluster.metadata.IndexMetadata.SETTING_VERSION_UPGRADED;
 import static org.opensearch.common.util.FeatureFlags.SEARCHABLE_SNAPSHOT_EXTENDED_COMPATIBILITY;
@@ -413,6 +416,13 @@ public ClusterState execute(ClusterState currentState) {
                                     overrideSettingsInternal,
                                     ignoreSettingsInternal
                                 );
+
+                                validateReplicationTypeRestoreSettings(
+                                    snapshot,
+                                    metadata.index(index).getSettings().get(SETTING_REPLICATION_TYPE),
+                                    snapshotIndexMetadata
+                                );
+
                                 if (isRemoteSnapshot) {
                                     snapshotIndexMetadata = addSnapshotToIndexSettings(snapshotIndexMetadata, snapshot, snapshotIndexId);
                                 }
@@ -1320,6 +1330,32 @@ private static void validateSnapshotRestorable(final String repository, final Sn
         }
     }
 
+    // Visible for testing
+    static void validateReplicationTypeRestoreSettings(Snapshot snapshot, String snapshotReplicationType, IndexMetadata updatedMetadata) {
+        int restoreNumberOfSearchReplicas = updatedMetadata.getSettings().getAsInt(SETTING_NUMBER_OF_SEARCH_REPLICAS, 0);
+
+        if (restoreNumberOfSearchReplicas > 0
+            && ReplicationType.DOCUMENT.toString().equals(updatedMetadata.getSettings().get(SETTING_REPLICATION_TYPE))) {
+            throw new SnapshotRestoreException(
+                snapshot,
+                "snapshot was created with ["
+                    + SETTING_REPLICATION_TYPE
+                    + "]"
+                    + " as ["
+                    + snapshotReplicationType
+                    + "]."
+                    + " To restore with ["
+                    + SETTING_REPLICATION_TYPE
+                    + "]"
+                    + " as ["
+                    + ReplicationType.DOCUMENT
+                    + "], ["
+                    + SETTING_NUMBER_OF_SEARCH_REPLICAS
+                    + "] must be set to [0]"
+            );
+        }
+    }
+
     public static boolean failed(SnapshotInfo snapshot, String index) {
         for (SnapshotShardFailure failure : snapshot.shardFailures()) {
             if (index.equals(failure.index())) {

server/src/test/java/org/opensearch/cluster/routing/SearchOnlyReplicaRestoreTests.java

@@ -0,0 +1,59 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ */
+
+package org.opensearch.cluster.routing;
+
+import org.opensearch.Version;
+import org.opensearch.cluster.ClusterName;
+import org.opensearch.cluster.ClusterState;
+import org.opensearch.cluster.metadata.IndexMetadata;
+import org.opensearch.cluster.metadata.Metadata;
+import org.opensearch.common.UUIDs;
+import org.opensearch.common.settings.Settings;
+import org.opensearch.repositories.IndexId;
+import org.opensearch.snapshots.Snapshot;
+import org.opensearch.snapshots.SnapshotId;
+import org.opensearch.test.OpenSearchTestCase;
+
+import java.util.HashSet;
+
+public class SearchOnlyReplicaRestoreTests extends OpenSearchTestCase {
+
+    public void testSearchOnlyReplicasRestored() {
+        Metadata metadata = Metadata.builder()
+            .put(
+                IndexMetadata.builder("test")
+                    .settings(settings(Version.CURRENT))
+                    .numberOfShards(1)
+                    .numberOfReplicas(1)
+                    .numberOfSearchReplicas(1)
+            )
+            .build();
+
+        IndexMetadata indexMetadata = metadata.index("test");
+        RecoverySource.SnapshotRecoverySource snapshotRecoverySource = new RecoverySource.SnapshotRecoverySource(
+            UUIDs.randomBase64UUID(),
+            new Snapshot("rep1", new SnapshotId("snp1", UUIDs.randomBase64UUID())),
+            Version.CURRENT,
+            new IndexId("test", UUIDs.randomBase64UUID(random()))
+        );
+
+        RoutingTable routingTable = RoutingTable.builder().addAsNewRestore(indexMetadata, snapshotRecoverySource, new HashSet<>()).build();
+
+        ClusterState clusterState = ClusterState.builder(ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY))
+            .metadata(metadata)
+            .routingTable(routingTable)
+            .build();
+
+        IndexShardRoutingTable indexShardRoutingTable = clusterState.routingTable().index("test").shard(0);
+
+        assertEquals(1, clusterState.routingTable().index("test").shards().size());
+        assertEquals(3, indexShardRoutingTable.getShards().size());
+        assertEquals(1, indexShardRoutingTable.searchOnlyReplicas().size());
+    }
+}