Add option to enable remote store for segments only

server/src/main/java/org/opensearch/cluster/metadata/MetadataCreateIndexService.java

@@ -227,9 +227,10 @@ public MetadataCreateIndexService(
         // Task is onboarded for throttling, it will get retried from associated TransportClusterManagerNodeAction.
         createIndexTaskKey = clusterService.registerClusterManagerTask(CREATE_INDEX, true);
         Supplier<Version> minNodeVersionSupplier = () -> clusterService.state().nodes().getMinNodeVersion();
-        remoteStoreCustomMetadataResolver = isRemoteDataAttributePresent(settings)
-            ? new RemoteStoreCustomMetadataResolver(remoteStoreSettings, minNodeVersionSupplier, repositoriesServiceSupplier, settings)
-            : null;
+        remoteStoreCustomMetadataResolver = RemoteStoreNodeAttribute.isSegmentRepoConfigured(settings)
+            && RemoteStoreNodeAttribute.isTranslogRepoConfigured(settings)
+                ? new RemoteStoreCustomMetadataResolver(remoteStoreSettings, minNodeVersionSupplier, repositoriesServiceSupplier, settings)
+                : null;
     }
 
     public IndexScopedSettings getIndexScopedSettings() {
@@ -1178,10 +1179,19 @@ public static void updateRemoteStoreSettings(
             if (remoteNode.isPresent()) {
                 translogRepo = RemoteStoreNodeAttribute.getTranslogRepoName(remoteNode.get().getAttributes());
                 segmentRepo = RemoteStoreNodeAttribute.getSegmentRepoName(remoteNode.get().getAttributes());
-                if (segmentRepo != null && translogRepo != null) {
-                    settingsBuilder.put(SETTING_REMOTE_STORE_ENABLED, true)
-                        .put(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, segmentRepo)
-                        .put(SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, translogRepo);
+                if (segmentRepo != null) {
+                    settingsBuilder.put(SETTING_REMOTE_STORE_ENABLED, true).put(SETTING_REMOTE_SEGMENT_STORE_REPOSITORY, segmentRepo);
+                    if (translogRepo != null) {
+                        settingsBuilder.put(SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, translogRepo);
+                    } else if (isMigratingToRemoteStore(clusterSettings)) {
+                        ValidationException validationException = new ValidationException();
+                        validationException.addValidationErrors(
+                            Collections.singletonList(
+                                "Cluster is migrating to remote store but remote translog is not configured, failing index creation"
+                            )
+                        );
+                        throw new IndexCreationException(indexName, validationException);
+                    }
                 } else {
                     ValidationException validationException = new ValidationException();
                     validationException.addValidationErrors(

server/src/main/java/org/opensearch/cluster/node/DiscoveryNode.java

@@ -506,6 +506,14 @@ public boolean isRemoteStoreNode() {
         return isClusterStateRepoConfigured(this.getAttributes()) && RemoteStoreNodeAttribute.isSegmentRepoConfigured(this.getAttributes());
     }
 
+    /**
+     * Returns whether the node is a remote segment store node.
+     * @return true if the node contains remote segment store node attributes, false otherwise
+     */
+    public boolean isRemoteSegmentStoreNode() {
+        return RemoteStoreNodeAttribute.isSegmentRepoConfigured(this.getAttributes());
+    }
+
     /**
      * Returns whether settings required for remote cluster state publication is configured
      * @return true if the node contains remote cluster state node attribute and remote routing table node attribute

server/src/main/java/org/opensearch/index/IndexService.java

@@ -673,7 +673,7 @@ public synchronized IndexShard createShard(
             Store remoteStore = null;
             Directory remoteDirectory = null;
             boolean seedRemote = false;
-            if (targetNode.isRemoteStoreNode()) {
+            if (targetNode.isRemoteSegmentStoreNode()) {
                 if (this.indexSettings.isRemoteStoreEnabled()) {
                     remoteDirectory = remoteDirectoryFactory.newDirectory(this.indexSettings, path);
                 } else {

server/src/main/java/org/opensearch/index/IndexSettings.java

@@ -1412,9 +1412,7 @@ public boolean isAssignedOnRemoteNode() {
      * Returns if remote translog store is enabled for this index.
      */
     public boolean isRemoteTranslogStoreEnabled() {
-        // Today enabling remote store automatically enables remote translog as well.
-        // which is why isRemoteStoreEnabled is used to represent isRemoteTranslogStoreEnabled
-        return isRemoteStoreEnabled;
+        return remoteStoreTranslogRepository != null && remoteStoreTranslogRepository.isEmpty() == false;
     }
 
     /**

server/src/main/java/org/opensearch/index/shard/IndexShard.java

@@ -2821,14 +2821,16 @@ private void innerOpenEngineAndTranslog(LongSupplier globalCheckpointSupplier, b
                     syncSegmentsFromRemoteSegmentStore(false);
                 }
                 if (shardRouting.primary()) {
-                    if (syncFromRemote) {
-                        syncRemoteTranslogAndUpdateGlobalCheckpoint();
-                    } else if (isSnapshotV2Restore() == false) {
-                        // we will enter this block when we do not want to recover from remote translog.
-                        // currently only during snapshot restore, we are coming into this block.
-                        // here, as while initiliazing remote translog we cannot skip downloading translog files,
-                        // so before that step, we are deleting the translog files present in remote store.
-                        deleteTranslogFilesFromRemoteTranslog();
+                    if (indexSettings.isRemoteTranslogStoreEnabled()) {
+                        if (syncFromRemote) {
+                            syncRemoteTranslogAndUpdateGlobalCheckpoint();
+                        } else if (isSnapshotV2Restore() == false) {
+                            // we will enter this block when we do not want to recover from remote translog.
+                            // currently only during snapshot restore, we are coming into this block.
+                            // here, as while initiliazing remote translog we cannot skip downloading translog files,
+                            // so before that step, we are deleting the translog files present in remote store.
+                            deleteTranslogFilesFromRemoteTranslog();
+                        }
                     }
                 } else if (syncFromRemote) {
                     // For replicas, when we download segments from remote segment store, we need to make sure that local

server/src/main/java/org/opensearch/indices/IndicesService.java

@@ -217,7 +217,6 @@
 import static org.opensearch.index.TieredMergePolicyProvider.MIN_DEFAULT_MAX_MERGE_AT_ONCE;
 import static org.opensearch.index.query.AbstractQueryBuilder.parseInnerQueryBuilder;
 import static org.opensearch.indices.IndicesRequestCache.INDICES_REQUEST_CACHE_MAX_SIZE_ALLOWED_IN_CACHE_SETTING;
-import static org.opensearch.node.remotestore.RemoteStoreNodeAttribute.isRemoteDataAttributePresent;
 import static org.opensearch.search.SearchService.ALLOW_EXPENSIVE_QUERIES;
 
 /**
@@ -707,7 +706,7 @@ private static BiFunction<IndexSettings, ShardRouting, TranslogFactory> getTrans
                     remoteStoreStatsTrackerFactory.getRemoteTranslogTransferTracker(shardRouting.shardId()),
                     remoteStoreSettings
                 );
-            } else if (isRemoteDataAttributePresent(settings) && shardRouting.primary()) {
+            } else if (RemoteStoreNodeAttribute.isTranslogRepoConfigured(settings) && shardRouting.primary()) {
                 return new RemoteBlobStoreInternalTranslogFactory(
                     repositoriesServiceSupplier,
                     threadPool,

server/src/main/java/org/opensearch/node/remotestore/RemoteStoreNodeAttribute.java

@@ -81,6 +81,8 @@ public class RemoteStoreNodeAttribute {
         REMOTE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEYS
     );
 
+    public static final String REMOTE_STORE_MODE_KEY = "remote_store.mode";
+
     /**
      * Creates a new {@link RemoteStoreNodeAttribute}
      */
@@ -190,17 +192,42 @@ private static Tuple<String, String> getValue(Map<String, String> attributes, Li
         return null;
     }
 
+    private enum RemoteStoreMode {
+        SEGMENTS_ONLY,
+        DEFAULT
+    }
+
     private Map<String, String> getValidatedRepositoryNames(DiscoveryNode node) {
         Set<Tuple<String, String>> repositoryNames = new HashSet<>();
-        if (containsKey(node.getAttributes(), REMOTE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEYS)
-            || containsKey(node.getAttributes(), REMOTE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEYS)) {
-            repositoryNames.add(validateAttributeNonNull(node, REMOTE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEYS));
-            repositoryNames.add(validateAttributeNonNull(node, REMOTE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEYS));
-            repositoryNames.add(validateAttributeNonNull(node, REMOTE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEYS));
-        } else if (containsKey(node.getAttributes(), REMOTE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEYS)) {
-            repositoryNames.add(validateAttributeNonNull(node, REMOTE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEYS));
+        RemoteStoreMode remoteStoreMode = RemoteStoreMode.DEFAULT;
+        if (containsKey(node.getAttributes(), List.of(REMOTE_STORE_MODE_KEY))) {
+            String mode = node.getAttributes().get(REMOTE_STORE_MODE_KEY);
+            if (mode != null && mode.equalsIgnoreCase(RemoteStoreMode.SEGMENTS_ONLY.name())) {
+                remoteStoreMode = RemoteStoreMode.SEGMENTS_ONLY;
+            } else if (mode != null && mode.equalsIgnoreCase(RemoteStoreMode.DEFAULT.name()) == false) {
+                throw new IllegalStateException("Unknown remote store mode [" + mode + "] for node [" + node + "]");
+            }
         }
+        if (remoteStoreMode == RemoteStoreMode.SEGMENTS_ONLY) {
+            repositoryNames.add(validateAttributeNonNull(node, REMOTE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEYS));
+        } else if (containsKey(node.getAttributes(), REMOTE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEYS)
+            || containsKey(node.getAttributes(), REMOTE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEYS)) {
+                repositoryNames.add(validateAttributeNonNull(node, REMOTE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEYS));
+                repositoryNames.add(validateAttributeNonNull(node, REMOTE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEYS));
+                repositoryNames.add(validateAttributeNonNull(node, REMOTE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEYS));
+            } else if (containsKey(node.getAttributes(), REMOTE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEYS)) {
+                repositoryNames.add(validateAttributeNonNull(node, REMOTE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEYS));
+            }
         if (containsKey(node.getAttributes(), REMOTE_ROUTING_TABLE_REPOSITORY_NAME_ATTRIBUTE_KEYS)) {
+            if (remoteStoreMode == RemoteStoreMode.SEGMENTS_ONLY) {
+                throw new IllegalStateException(
+                    "Cannot set "
+                        + REMOTE_ROUTING_TABLE_REPOSITORY_NAME_ATTRIBUTE_KEYS
+                        + " attributes when remote store mode is set to segments only for node ["
+                        + node
+                        + "]"
+                );
+            }
             repositoryNames.add(validateAttributeNonNull(node, REMOTE_ROUTING_TABLE_REPOSITORY_NAME_ATTRIBUTE_KEYS));
         }
 

server/src/test/java/org/opensearch/cluster/coordination/JoinTaskExecutorTests.java

@@ -662,7 +662,7 @@ public void testJoinRemotePubClusterWithRemoteStoreNodes() {
             IllegalStateException.class,
             () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
         );
-        assertTrue(e.getMessage().equals("a remote store node [" + joiningNode + "] is trying to join a non remote store cluster"));
+        assertEquals("a remote store node [" + joiningNode + "] is trying to join a non remote store cluster", e.getMessage());
     }
 
     public void testPreventJoinRemotePublicationClusterWithIncompatibleAttributes() {
@@ -719,7 +719,7 @@ public void testPreventJoinClusterWithRemoteStateNodeJoiningRemoteStoreCluster()
             IllegalStateException.class,
             () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
         );
-        assertTrue(e.getMessage().equals("a non remote store node [" + joiningNode + "] is trying to join a remote store cluster"));
+        assertEquals("a non remote store node [" + joiningNode + "] is trying to join a remote store cluster", e.getMessage());
     }
 
     public void testPreventJoinClusterWithRemoteStoreNodeJoiningRemoteStateCluster() {
@@ -739,7 +739,7 @@ public void testPreventJoinClusterWithRemoteStoreNodeJoiningRemoteStateCluster()
             IllegalStateException.class,
             () -> JoinTaskExecutor.ensureNodesCompatibility(joiningNode, currentState.getNodes(), currentState.metadata())
         );
-        assertTrue(e.getMessage().equals("a remote store node [" + joiningNode + "] is trying to join a non remote store cluster"));
+        assertEquals("a remote store node [" + joiningNode + "] is trying to join a non remote store cluster", e.getMessage());
     }
 
     public void testUpdatesClusterStateWithSingleNodeCluster() throws Exception {

server/src/test/java/org/opensearch/cluster/metadata/MetadataCreateIndexServiceTests.java

@@ -1702,7 +1702,7 @@ public void testNewIndexIsRemoteStoreBackedForRemoteStoreDirectionAndMixedMode()
         assertEquals(error.getMessage(), "failed to create index [test-index]");
         assertThat(
             error.getCause().getMessage(),
-            containsString("Cluster is migrating to remote store but no remote node found, failing index creation")
+            containsString("Cluster is migrating to remote store but remote translog is not configured, failing index creation")
         );
     }
 
@@ -1771,6 +1771,8 @@ private IndexMetadata testRemoteCustomData(boolean remoteStoreEnabled, PathType
         Settings.Builder settingsBuilder = Settings.builder();
         if (remoteStoreEnabled) {
             settingsBuilder.put(NODE_ATTRIBUTES.getKey() + REMOTE_STORE_SEGMENT_REPOSITORY_NAME_ATTRIBUTE_KEY, "test");
+            settingsBuilder.put(NODE_ATTRIBUTES.getKey() + REMOTE_STORE_TRANSLOG_REPOSITORY_NAME_ATTRIBUTE_KEY, "test");
+            settingsBuilder.put(NODE_ATTRIBUTES.getKey() + REMOTE_STORE_CLUSTER_STATE_REPOSITORY_NAME_ATTRIBUTE_KEY, "test");
         }
         settingsBuilder.put(RemoteStoreSettings.CLUSTER_REMOTE_STORE_PATH_TYPE_SETTING.getKey(), pathType.toString());
         Settings settings = settingsBuilder.build();

server/src/test/java/org/opensearch/index/seqno/ReplicationTrackerTests.java

@@ -1570,6 +1570,7 @@ public void testInSyncIdsAreIgnoredIfNotValidatedByClusterManagerWithRemoteTrans
         Settings settings = Settings.builder()
             .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
             .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, "true")
+            .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "translog-repo")
             .build();
         final ReplicationTracker tracker = newTracker(primaryId, settings);
         tracker.updateFromClusterManager(randomNonNegativeLong(), ids(active.keySet()), routingTable(initializing.keySet(), primaryId));

server/src/test/java/org/opensearch/index/shard/IndexShardTests.java

@@ -1825,6 +1825,7 @@ public void testShardStatsWithRemoteStoreEnabled() throws IOException {
             Settings.builder()
                 .put(IndexMetadata.SETTING_REPLICATION_TYPE, "SEGMENT")
                 .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+                .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "translog-repo")
                 .build()
         );
         RemoteSegmentTransferTracker remoteSegmentTransferTracker = shard.getRemoteStoreStatsTrackerFactory()

server/src/test/java/org/opensearch/index/store/remote/metadata/RemoteSegmentMetadataHandlerTests.java

@@ -50,6 +50,7 @@ public void setup() throws IOException {
             .put(IndexMetadata.SETTING_VERSION_CREATED, org.opensearch.Version.CURRENT)
             .put(IndexMetadata.SETTING_REPLICATION_TYPE, ReplicationType.SEGMENT)
             .put(IndexMetadata.SETTING_REMOTE_STORE_ENABLED, true)
+            .put(IndexMetadata.SETTING_REMOTE_TRANSLOG_STORE_REPOSITORY, "translog-repo")
             .build();
 
         indexShard = newStartedShard(false, indexSettings, new NRTReplicationEngineFactory());