[Backport 2.17] Add path prefix support to hashed prefix snapshots (#15664)

CHANGELOG.md

@@ -5,6 +5,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased 2.17.x]
 ### Added
+- Add path prefix support to hashed prefix snapshots ([#15664](https://github.com/opensearch-project/OpenSearch/pull/15664))
 
 ### Dependencies
 

server/src/main/java/org/opensearch/common/settings/ClusterSettings.java

@@ -152,6 +152,7 @@
 import org.opensearch.ratelimitting.admissioncontrol.AdmissionControlSettings;
 import org.opensearch.ratelimitting.admissioncontrol.settings.CpuBasedAdmissionControllerSettings;
 import org.opensearch.ratelimitting.admissioncontrol.settings.IoBasedAdmissionControllerSettings;
+import org.opensearch.repositories.blobstore.BlobStoreRepository;
 import org.opensearch.repositories.fs.FsRepository;
 import org.opensearch.rest.BaseRestHandler;
 import org.opensearch.script.ScriptService;
@@ -773,6 +774,7 @@ public void apply(Settings value, Settings current, Settings previous) {
                 RemoteStoreSettings.CLUSTER_REMOTE_STORE_PINNED_TIMESTAMP_ENABLED,
                 RemoteStoreSettings.CLUSTER_REMOTE_STORE_SEGMENTS_PATH_PREFIX,
                 RemoteStoreSettings.CLUSTER_REMOTE_STORE_TRANSLOG_PATH_PREFIX,
+                BlobStoreRepository.SNAPSHOT_SHARD_PATH_PREFIX_SETTING,
 
                 // Composite index settings
                 CompositeIndexSettings.STAR_TREE_INDEX_ENABLED_SETTING,

server/src/main/java/org/opensearch/repositories/blobstore/BlobStoreRepository.java

@@ -344,6 +344,16 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
         Setting.Property.NodeScope
     );
 
+    /**
+     * Controls the fixed prefix for the snapshot shard blob path.
+     */
+    public static final Setting<String> SNAPSHOT_SHARD_PATH_PREFIX_SETTING = Setting.simpleString(
+        "cluster.snapshot.shard.path.prefix",
+        "",
+        Setting.Property.NodeScope,
+        Setting.Property.Final
+    );
+
     protected volatile boolean supportURLRepo;
 
     private volatile int maxShardBlobDeleteBatch;
@@ -435,6 +445,8 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
 
     private final NamedXContentRegistry namedXContentRegistry;
 
+    private final String snapshotShardPathPrefix;
+
     /**
      * Flag that is set to {@code true} if this instance is started with {@link #metadata} that has a higher value for
      * {@link RepositoryMetadata#pendingGeneration()} than for {@link RepositoryMetadata#generation()} indicating a full cluster restart
@@ -489,6 +501,7 @@ protected BlobStoreRepository(
         this.clusterService = clusterService;
         this.recoverySettings = recoverySettings;
         this.remoteStoreSettings = new RemoteStoreSettings(clusterService.getSettings(), clusterService.getClusterSettings());
+        this.snapshotShardPathPrefix = SNAPSHOT_SHARD_PATH_PREFIX_SETTING.get(clusterService.getSettings());
     }
 
     @Override
@@ -2828,6 +2841,7 @@ private BlobPath shardPath(IndexId indexId, int shardId) {
         SnapshotShardPathInput shardPathInput = new SnapshotShardPathInput.Builder().basePath(basePath())
             .indexUUID(indexId.getId())
             .shardId(String.valueOf(shardId))
+            .fixedPrefix(snapshotShardPathPrefix)
             .build();
         PathHashAlgorithm pathHashAlgorithm = pathType != PathType.FIXED ? FNV_1A_COMPOSITE_1 : null;
         return pathType.path(shardPathInput, pathHashAlgorithm);

test/framework/src/main/java/org/opensearch/test/OpenSearchIntegTestCase.java

@@ -408,11 +408,14 @@ public abstract class OpenSearchIntegTestCase extends OpenSearchTestCase {
 
     private static Boolean segmentsPathFixedPrefix;
 
+    private static Boolean snapshotShardPathFixedPrefix;
+
     @BeforeClass
     public static void beforeClass() throws Exception {
         prefixModeVerificationEnable = randomBoolean();
         translogPathFixedPrefix = randomBoolean();
         segmentsPathFixedPrefix = randomBoolean();
+        snapshotShardPathFixedPrefix = randomBoolean();
         testClusterRule.beforeClass();
     }
 
@@ -2920,6 +2923,7 @@ private static Settings buildRemoteStoreNodeAttributes(
         settings.put(RemoteStoreSettings.CLUSTER_REMOTE_STORE_PINNED_TIMESTAMP_ENABLED.getKey(), false);
         settings.put(RemoteStoreSettings.CLUSTER_REMOTE_STORE_SEGMENTS_PATH_PREFIX.getKey(), translogPathFixedPrefix ? "a" : "");
         settings.put(RemoteStoreSettings.CLUSTER_REMOTE_STORE_TRANSLOG_PATH_PREFIX.getKey(), segmentsPathFixedPrefix ? "b" : "");
+        settings.put(BlobStoreRepository.SNAPSHOT_SHARD_PATH_PREFIX_SETTING.getKey(), segmentsPathFixedPrefix ? "c" : "");
         return settings.build();
     }