Fix red index on flush

Signed-off-by: Ashish Singh <ssashish@amazon.com>

server/src/internalClusterTest/java/org/opensearch/remotestore/RemoteStoreBackpressureAndResiliencyIT.java

@@ -11,6 +11,7 @@
 import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStats;
 import org.opensearch.action.admin.cluster.remotestore.stats.RemoteStoreStatsResponse;
 import org.opensearch.action.admin.cluster.settings.ClusterUpdateSettingsResponse;
+import org.opensearch.action.admin.indices.flush.FlushResponse;
 import org.opensearch.common.settings.Settings;
 import org.opensearch.common.unit.TimeValue;
 import org.opensearch.common.util.concurrent.AbstractAsyncTask;
@@ -228,4 +229,32 @@ public void testSkipLoadGlobalCheckpointToReplicationTracker() {
         client().admin().cluster().prepareReroute().setRetryFailed(true).get();
         ensureGreen(INDEX_NAME);
     }
+
+    public void testFlushDuringRemoteUploadFailures() {
+        Path location = randomRepoPath().toAbsolutePath();
+        String dataNodeName = setup(location, 0d, "metadata", Long.MAX_VALUE);
+
+        logger.info("--> Indexing data");
+        indexData(randomIntBetween(1, 2), true);
+        logger.info("--> Indexing succeeded");
+        ensureGreen(INDEX_NAME);
+
+        MockRepository translogRepo = (MockRepository) internalCluster().getInstance(RepositoriesService.class, dataNodeName)
+            .repository(TRANSLOG_REPOSITORY_NAME);
+        logger.info("--> Failing all remote store interaction");
+        translogRepo.setRandomControlIOExceptionRate(1d);
+
+        Exception ex = assertThrows(UncategorizedExecutionException.class, () -> indexSingleDoc());
+        assertEquals("Failed execution", ex.getMessage());
+
+        FlushResponse flushResponse = client().admin().indices().prepareFlush(INDEX_NAME).setForce(true).execute().actionGet();
+        assertEquals(1, flushResponse.getFailedShards());
+        ensureGreen(INDEX_NAME);
+
+        logger.info("--> Stop failing all remote store interactions");
+        translogRepo.setRandomControlIOExceptionRate(0d);
+        flushResponse = client().admin().indices().prepareFlush(INDEX_NAME).setForce(true).execute().actionGet();
+        assertEquals(1, flushResponse.getSuccessfulShards());
+        assertEquals(0, flushResponse.getFailedShards());
+    }
 }

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

@@ -1475,7 +1475,7 @@ public void trimTranslog() {
     /**
      * Rolls the tranlog generation and cleans unneeded.
      */
-    public void rollTranslogGeneration() {
+    public void rollTranslogGeneration() throws IOException {
         final Engine engine = getEngine();
         engine.translogManager().rollTranslogGeneration();
     }

server/src/main/java/org/opensearch/index/translog/InternalTranslogManager.java

@@ -18,6 +18,7 @@
 import org.opensearch.index.engine.LifecycleAware;
 import org.opensearch.index.seqno.LocalCheckpointTracker;
 import org.opensearch.index.translog.listener.TranslogEventListener;
+import org.opensearch.index.translog.transfer.TranslogUploadFailedException;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -83,11 +84,14 @@ public InternalTranslogManager(
      * Rolls the translog generation and cleans unneeded.
      */
     @Override
-    public void rollTranslogGeneration() throws TranslogException {
+    public void rollTranslogGeneration() throws TranslogException, IOException {
         try (ReleasableLock ignored = readLock.acquire()) {
             engineLifeCycleAware.ensureOpen();
             translog.rollGeneration();
             translog.trimUnreferencedReaders();
+        } catch (TranslogUploadFailedException e) {
+            // Do not trigger the translogEventListener as it fails the Engine while this is only an issue with remote upload
+            throw e;
         } catch (AlreadyClosedException e) {
             translogEventListener.onFailure("translog roll generation failed", e);
             throw e;

server/src/main/java/org/opensearch/index/translog/TranslogManager.java

@@ -21,7 +21,7 @@ public interface TranslogManager {
     /**
      * Rolls the translog generation and cleans unneeded.
      */
-    void rollTranslogGeneration() throws TranslogException;
+    void rollTranslogGeneration() throws TranslogException, IOException;
 
     /**
      * Performs recovery from the transaction log up to {@code recoverUpToSeqNo} (inclusive).

server/src/main/java/org/opensearch/index/translog/transfer/TranslogTransferManager.java

@@ -176,7 +176,7 @@ public boolean transferSnapshot(TransferSnapshot transferSnapshot, TranslogTrans
                     remoteTranslogTransferTracker.addUploadTimeInMillis((System.nanoTime() - metadataUploadStartTime) / 1_000_000L);
                     remoteTranslogTransferTracker.addUploadBytesFailed(metadataBytesToUpload);
                     // outer catch handles capturing stats on upload failure
-                    throw exception;
+                    throw new TranslogUploadFailedException("Failed to upload " + tlogMetadata.getName(), exception);
                 }
 
                 remoteTranslogTransferTracker.addUploadTimeInMillis((System.nanoTime() - metadataUploadStartTime) / 1_000_000L);
@@ -185,7 +185,7 @@ public boolean transferSnapshot(TransferSnapshot transferSnapshot, TranslogTrans
                 translogTransferListener.onUploadComplete(transferSnapshot);
                 return true;
             } else {
-                Exception ex = new IOException("Failed to upload " + exceptionList.size() + " files during transfer");
+                Exception ex = new TranslogUploadFailedException("Failed to upload " + exceptionList.size() + " files during transfer");
                 exceptionList.forEach(ex::addSuppressed);
                 throw ex;
             }

server/src/main/java/org/opensearch/index/translog/transfer/TranslogUploadFailedException.java

@@ -0,0 +1,27 @@
+/*
+ * 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.index.translog.transfer;
+
+import java.io.IOException;
+
+/**
+ * Exception is thrown if there are any exceptions while uploading translog to remote store.
+ * @opensearch.internal
+ */
+public class TranslogUploadFailedException extends IOException {
+
+    public TranslogUploadFailedException(String message) {
+        super(message);
+    }
+
+    public TranslogUploadFailedException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+}

server/src/test/java/org/opensearch/index/engine/InternalEngineTests.java

@@ -7256,7 +7256,11 @@ public void testMaxSeqNoInCommitUserData() throws Exception {
             engine.ensureOpen();
             while (running.get()
                 && assertAndGetInternalTranslogManager(engine.translogManager()).getTranslog().currentFileGeneration() < 500) {
-                engine.translogManager().rollTranslogGeneration(); // make adding operations to translog slower
+                try {
+                    engine.translogManager().rollTranslogGeneration(); // make adding operations to translog slower
+                } catch (IOException e) {
+                    fail("io exception not expected");
+                }
             }
         });
         rollTranslog.start();

server/src/test/java/org/opensearch/index/translog/RemoteFsTranslogTests.java

@@ -47,6 +47,7 @@
 import org.opensearch.index.translog.transfer.BlobStoreTransferService;
 import org.opensearch.index.translog.transfer.TranslogTransferManager;
 import org.opensearch.index.translog.transfer.TranslogTransferMetadata;
+import org.opensearch.index.translog.transfer.TranslogUploadFailedException;
 import org.opensearch.indices.recovery.RecoverySettings;
 import org.opensearch.indices.replication.common.ReplicationType;
 import org.opensearch.repositories.blobstore.BlobStoreRepository;
@@ -1113,7 +1114,7 @@ public void testSyncUpAlwaysFailure() throws IOException {
             try {
                 translog.sync();
                 fail("io exception expected");
-            } catch (IOException e) {
+            } catch (TranslogUploadFailedException e) {
                 assertTrue("at least one operation pending", translog.syncNeeded());
             }
         }