From 506449bf9deae465d1760bcab271a2231c7f9d18 Mon Sep 17 00:00:00 2001 From: Tanguy Leroux Date: Fri, 24 Nov 2017 13:15:34 +0100 Subject: [PATCH] Delete shard store files before restoring a snapshot (#27476) Pull request #20220 added a change where the store files that have the same name but are different from the ones in the snapshot are deleted first before the snapshot is restored. This logic was based on the `Store.RecoveryDiff.different` set of files which works by computing a diff between an existing store and a snapshot. This works well when the files on the filesystem form valid shard store, ie there's a `segments` file and store files are not corrupted. Otherwise, the existing store's snapshot metadata cannot be read (using Store#snapshotStoreMetadata()) and an exception is thrown (CorruptIndexException, IndexFormatTooOldException etc) which is later caught as the begining of the restore process (see RestoreContext#restore()) and is translated into an empty store metadata (Store.MetadataSnapshot.EMPTY). This will make the deletion of different files introduced in #20220 useless as the set of files will always be empty even when store files exist on the filesystem. And if some files are present within the store directory, then restoring a snapshot with files with same names will fail with a FileAlreadyExistException. This is part of the #26865 issue. There are various cases were some files could exist in the store directory before a snapshot is restored. One that Igor identified is a restore attempt that failed on a node and only first files were restored, then the shard is allocated again to the same node and the restore starts again (but fails because of existing files). Another one is when some files of a closed index are corrupted / deleted and the index is restored. This commit adds a test that uses the infrastructure provided by IndexShardTestCase in order to test that restoring a shard succeed even when files with same names exist on filesystem. Related to #26865 --- .../org/elasticsearch/index/store/Store.java | 2 +- .../blobstore/BlobStoreRepository.java | 43 ++++-- .../snapshots/RestoreService.java | 2 +- .../BlobStoreRepositoryRestoreTests.java | 142 ++++++++++++++++++ .../index/shard/IndexShardTestCase.java | 38 +++++ 5 files changed, 209 insertions(+), 18 deletions(-) create mode 100644 core/src/test/java/org/elasticsearch/repositories/blobstore/BlobStoreRepositoryRestoreTests.java diff --git a/core/src/main/java/org/elasticsearch/index/store/Store.java b/core/src/main/java/org/elasticsearch/index/store/Store.java index fa992e12ef220..902cf4b992b11 100644 --- a/core/src/main/java/org/elasticsearch/index/store/Store.java +++ b/core/src/main/java/org/elasticsearch/index/store/Store.java @@ -731,7 +731,7 @@ public String toString() { /** * Represents a snapshot of the current directory build from the latest Lucene commit. - * Only files that are part of the last commit are considered in this datastrucutre. + * Only files that are part of the last commit are considered in this datastructure. * For backwards compatibility the snapshot might include legacy checksums that * are derived from a dedicated checksum file written by older elasticsearch version pre 1.3 *

diff --git a/core/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java b/core/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java index 939c33d00a8d4..84d3d743f6402 100644 --- a/core/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java +++ b/core/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java @@ -35,7 +35,6 @@ import org.apache.lucene.store.RateLimiter; import org.apache.lucene.util.BytesRef; import org.apache.lucene.util.BytesRefBuilder; -import org.apache.lucene.util.IOUtils; import org.elasticsearch.ElasticsearchParseException; import org.elasticsearch.ExceptionsHelper; import org.elasticsearch.ResourceNotFoundException; @@ -110,6 +109,7 @@ import java.nio.file.FileAlreadyExistsException; import java.nio.file.NoSuchFileException; import java.util.ArrayList; +import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.HashMap; @@ -1451,6 +1451,9 @@ public void restore() throws IOException { SnapshotFiles snapshotFiles = new SnapshotFiles(snapshot.snapshot(), snapshot.indexFiles()); Store.MetadataSnapshot recoveryTargetMetadata; try { + // this will throw an IOException if the store has no segments infos file. The + // store can still have existing files but they will be deleted just before being + // restored. recoveryTargetMetadata = targetShard.snapshotStoreMetadata(); } catch (IndexNotFoundException e) { // happens when restore to an empty shard, not a big deal @@ -1478,7 +1481,14 @@ public void restore() throws IOException { snapshotMetaData.put(fileInfo.metadata().name(), fileInfo.metadata()); fileInfos.put(fileInfo.metadata().name(), fileInfo); } + final Store.MetadataSnapshot sourceMetaData = new Store.MetadataSnapshot(unmodifiableMap(snapshotMetaData), emptyMap(), 0); + + final StoreFileMetaData restoredSegmentsFile = sourceMetaData.getSegmentsFile(); + if (restoredSegmentsFile == null) { + throw new IndexShardRestoreFailedException(shardId, "Snapshot has no segments file"); + } + final Store.RecoveryDiff diff = sourceMetaData.recoveryDiff(recoveryTargetMetadata); for (StoreFileMetaData md : diff.identical) { BlobStoreIndexShardSnapshot.FileInfo fileInfo = fileInfos.get(md.name()); @@ -1505,29 +1515,31 @@ public void restore() throws IOException { logger.trace("no files to recover, all exists within the local store"); } - if (logger.isTraceEnabled()) { - logger.trace("[{}] [{}] recovering_files [{}] with total_size [{}], reusing_files [{}] with reused_size [{}]", shardId, snapshotId, - index.totalRecoverFiles(), new ByteSizeValue(index.totalRecoverBytes()), index.reusedFileCount(), new ByteSizeValue(index.reusedFileCount())); - } try { - // first, delete pre-existing files in the store that have the same name but are - // different (i.e. different length/checksum) from those being restored in the snapshot - for (final StoreFileMetaData storeFileMetaData : diff.different) { - IOUtils.deleteFiles(store.directory(), storeFileMetaData.name()); - } + // list of all existing store files + final List deleteIfExistFiles = Arrays.asList(store.directory().listAll()); + // restore the files from the snapshot to the Lucene store for (final BlobStoreIndexShardSnapshot.FileInfo fileToRecover : filesToRecover) { + // if a file with a same physical name already exist in the store we need to delete it + // before restoring it from the snapshot. We could be lenient and try to reuse the existing + // store files (and compare their names/length/checksum again with the snapshot files) but to + // avoid extra complexity we simply delete them and restore them again like StoreRecovery + // does with dangling indices. Any existing store file that is not restored from the snapshot + // will be clean up by RecoveryTarget.cleanFiles(). + final String physicalName = fileToRecover.physicalName(); + if (deleteIfExistFiles.contains(physicalName)) { + logger.trace("[{}] [{}] deleting pre-existing file [{}]", shardId, snapshotId, physicalName); + store.directory().deleteFile(physicalName); + } + logger.trace("[{}] [{}] restoring file [{}]", shardId, snapshotId, fileToRecover.name()); restoreFile(fileToRecover, store); } } catch (IOException ex) { throw new IndexShardRestoreFailedException(shardId, "Failed to recover index", ex); } - final StoreFileMetaData restoredSegmentsFile = sourceMetaData.getSegmentsFile(); - if (recoveryTargetMetadata == null) { - throw new IndexShardRestoreFailedException(shardId, "Snapshot has no segments file"); - } - assert restoredSegmentsFile != null; + // read the snapshot data persisted final SegmentInfos segmentCommitInfos; try { @@ -1602,5 +1614,4 @@ private void restoreFile(final BlobStoreIndexShardSnapshot.FileInfo fileInfo, fi } } } - } diff --git a/core/src/main/java/org/elasticsearch/snapshots/RestoreService.java b/core/src/main/java/org/elasticsearch/snapshots/RestoreService.java index e6e6bc82173bf..f88299661828c 100644 --- a/core/src/main/java/org/elasticsearch/snapshots/RestoreService.java +++ b/core/src/main/java/org/elasticsearch/snapshots/RestoreService.java @@ -188,7 +188,7 @@ public void restoreSnapshot(final RestoreRequest request, final ActionListener filteredIndices = SnapshotUtils.filterIndices(snapshotInfo.indices(), request.indices(), request.indicesOptions()); - MetaData metaData = repository.getSnapshotMetaData(snapshotInfo, repositoryData.resolveIndices(filteredIndices)); + final MetaData metaData = repository.getSnapshotMetaData(snapshotInfo, repositoryData.resolveIndices(filteredIndices)); // Make sure that we can restore from this snapshot validateSnapshotRestorable(request.repositoryName, snapshotInfo); diff --git a/core/src/test/java/org/elasticsearch/repositories/blobstore/BlobStoreRepositoryRestoreTests.java b/core/src/test/java/org/elasticsearch/repositories/blobstore/BlobStoreRepositoryRestoreTests.java new file mode 100644 index 0000000000000..8470b46ceb939 --- /dev/null +++ b/core/src/test/java/org/elasticsearch/repositories/blobstore/BlobStoreRepositoryRestoreTests.java @@ -0,0 +1,142 @@ +/* + * Licensed to Elasticsearch under one or more contributor + * license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright + * ownership. Elasticsearch licenses this file to you under + * the Apache License, Version 2.0 (the "License"); you may + * not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +package org.elasticsearch.repositories.blobstore; + +import org.apache.lucene.store.Directory; +import org.apache.lucene.util.IOUtils; +import org.apache.lucene.util.TestUtil; +import org.elasticsearch.cluster.metadata.RepositoryMetaData; +import org.elasticsearch.cluster.routing.ShardRouting; +import org.elasticsearch.cluster.routing.ShardRoutingHelper; +import org.elasticsearch.common.UUIDs; +import org.elasticsearch.common.settings.Settings; +import org.elasticsearch.env.Environment; +import org.elasticsearch.index.shard.IndexShard; +import org.elasticsearch.index.shard.IndexShardState; +import org.elasticsearch.index.shard.IndexShardTestCase; +import org.elasticsearch.index.shard.ShardId; +import org.elasticsearch.index.store.Store; +import org.elasticsearch.index.store.StoreFileMetaData; +import org.elasticsearch.repositories.IndexId; +import org.elasticsearch.repositories.Repository; +import org.elasticsearch.repositories.fs.FsRepository; +import org.elasticsearch.snapshots.Snapshot; +import org.elasticsearch.snapshots.SnapshotId; + +import java.io.IOException; +import java.nio.file.Files; +import java.nio.file.Path; +import java.util.Arrays; +import java.util.List; + +import static org.elasticsearch.cluster.routing.RecoverySource.StoreRecoverySource.EXISTING_STORE_INSTANCE; + +/** + * This class tests the behavior of {@link BlobStoreRepository} when it + * restores a shard from a snapshot but some files with same names already + * exist on disc. + */ +public class BlobStoreRepositoryRestoreTests extends IndexShardTestCase { + + /** + * Restoring a snapshot that contains multiple files must succeed even when + * some files already exist in the shard's store. + */ + public void testRestoreSnapshotWithExistingFiles() throws IOException { + final IndexId indexId = new IndexId(randomAlphaOfLength(10), UUIDs.randomBase64UUID()); + final ShardId shardId = new ShardId(indexId.getName(), indexId.getId(), 0); + + IndexShard shard = newShard(shardId, true); + try { + // index documents in the shards + final int numDocs = scaledRandomIntBetween(1, 500); + recoverShardFromStore(shard); + for (int i = 0; i < numDocs; i++) { + indexDoc(shard, "doc", Integer.toString(i)); + if (rarely()) { + flushShard(shard, false); + } + } + assertDocCount(shard, numDocs); + + // snapshot the shard + final Repository repository = createRepository(); + final Snapshot snapshot = new Snapshot(repository.getMetadata().name(), new SnapshotId(randomAlphaOfLength(10), "_uuid")); + snapshotShard(shard, snapshot, repository); + + // capture current store files + final Store.MetadataSnapshot storeFiles = shard.snapshotStoreMetadata(); + assertFalse(storeFiles.asMap().isEmpty()); + + // close the shard + closeShards(shard); + + // delete some random files in the store + List deletedFiles = randomSubsetOf(randomIntBetween(1, storeFiles.size() - 1), storeFiles.asMap().keySet()); + for (String deletedFile : deletedFiles) { + Files.delete(shard.shardPath().resolveIndex().resolve(deletedFile)); + } + + // build a new shard using the same store directory as the closed shard + ShardRouting shardRouting = ShardRoutingHelper.initWithSameId(shard.routingEntry(), EXISTING_STORE_INSTANCE); + shard = newShard(shardRouting, shard.shardPath(), shard.indexSettings().getIndexMetaData(), null, null, () -> {}); + + // restore the shard + recoverShardFromSnapshot(shard, snapshot, repository); + + // check that the shard is not corrupted + TestUtil.checkIndex(shard.store().directory()); + + // check that all files have been restored + final Directory directory = shard.store().directory(); + final List directoryFiles = Arrays.asList(directory.listAll()); + + for (StoreFileMetaData storeFile : storeFiles) { + String fileName = storeFile.name(); + assertTrue("File [" + fileName + "] does not exist in store directory", directoryFiles.contains(fileName)); + assertEquals(storeFile.length(), shard.store().directory().fileLength(fileName)); + } + } finally { + if (shard != null && shard.state() != IndexShardState.CLOSED) { + try { + shard.close("test", false); + } finally { + IOUtils.close(shard.store()); + } + } + } + } + + /** Create a {@link Repository} with a random name **/ + private Repository createRepository() throws IOException { + Settings settings = Settings.builder().put("location", randomAlphaOfLength(10)).build(); + RepositoryMetaData repositoryMetaData = new RepositoryMetaData(randomAlphaOfLength(10), FsRepository.TYPE, settings); + return new FsRepository(repositoryMetaData, createEnvironment(), xContentRegistry()); + } + + /** Create a {@link Environment} with random path.home and path.repo **/ + private Environment createEnvironment() { + Path home = createTempDir(); + return new Environment(Settings.builder() + .put(Environment.PATH_HOME_SETTING.getKey(), home.toAbsolutePath()) + .put(Environment.PATH_REPO_SETTING.getKey(), home.resolve("repo").toAbsolutePath()) + .build()); + } +} diff --git a/test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java b/test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java index a448444edce1c..242cdfcfd7e5e 100644 --- a/test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java +++ b/test/framework/src/main/java/org/elasticsearch/index/shard/IndexShardTestCase.java @@ -46,6 +46,7 @@ import org.elasticsearch.common.util.BigArrays; import org.elasticsearch.common.xcontent.XContentType; import org.elasticsearch.env.NodeEnvironment; +import org.elasticsearch.index.Index; import org.elasticsearch.index.IndexSettings; import org.elasticsearch.index.MapperTestUtils; import org.elasticsearch.index.VersionType; @@ -60,6 +61,7 @@ import org.elasticsearch.index.mapper.Uid; import org.elasticsearch.index.seqno.SequenceNumbers; import org.elasticsearch.index.similarity.SimilarityService; +import org.elasticsearch.index.snapshots.IndexShardSnapshotStatus; import org.elasticsearch.index.store.DirectoryService; import org.elasticsearch.index.store.Store; import org.elasticsearch.indices.recovery.PeerRecoveryTargetService; @@ -69,6 +71,9 @@ import org.elasticsearch.indices.recovery.RecoveryTarget; import org.elasticsearch.indices.recovery.StartRecoveryRequest; import org.elasticsearch.node.Node; +import org.elasticsearch.repositories.IndexId; +import org.elasticsearch.repositories.Repository; +import org.elasticsearch.snapshots.Snapshot; import org.elasticsearch.test.DummyShardLock; import org.elasticsearch.test.ESTestCase; import org.elasticsearch.threadpool.TestThreadPool; @@ -85,6 +90,7 @@ import java.util.function.BiFunction; import java.util.function.Consumer; +import static org.elasticsearch.cluster.routing.TestShardRouting.newShardRouting; import static org.hamcrest.Matchers.contains; import static org.hamcrest.Matchers.hasSize; @@ -583,6 +589,38 @@ protected void flushShard(IndexShard shard, boolean force) { shard.flush(new FlushRequest(shard.shardId().getIndexName()).force(force)); } + /** Recover a shard from a snapshot using a given repository **/ + protected void recoverShardFromSnapshot(final IndexShard shard, + final Snapshot snapshot, + final Repository repository) throws IOException { + final Version version = Version.CURRENT; + final ShardId shardId = shard.shardId(); + final String index = shardId.getIndexName(); + final IndexId indexId = new IndexId(shardId.getIndex().getName(), shardId.getIndex().getUUID()); + final DiscoveryNode node = getFakeDiscoNode(shard.routingEntry().currentNodeId()); + final RecoverySource.SnapshotRecoverySource recoverySource = new RecoverySource.SnapshotRecoverySource(snapshot, version, index); + final ShardRouting shardRouting = newShardRouting(shardId, node.getId(), true, ShardRoutingState.INITIALIZING, recoverySource); + + shard.markAsRecovering("from snapshot", new RecoveryState(shardRouting, node, null)); + repository.restoreShard(shard, snapshot.getSnapshotId(), version, indexId, shard.shardId(), shard.recoveryState()); + } + + /** Snapshot a shard using a given repository **/ + protected void snapshotShard(final IndexShard shard, + final Snapshot snapshot, + final Repository repository) throws IOException { + final IndexShardSnapshotStatus snapshotStatus = new IndexShardSnapshotStatus(); + try (Engine.IndexCommitRef indexCommitRef = shard.acquireIndexCommit(true)) { + Index index = shard.shardId().getIndex(); + IndexId indexId = new IndexId(index.getName(), index.getUUID()); + + repository.snapshotShard(shard, snapshot.getSnapshotId(), indexId, indexCommitRef.getIndexCommit(), snapshotStatus); + } + assertEquals(IndexShardSnapshotStatus.Stage.DONE, snapshotStatus.stage()); + assertEquals(shard.snapshotStoreMetadata().size(), snapshotStatus.numberOfFiles()); + assertNull(snapshotStatus.failure()); + } + /** * Helper method to access (package-protected) engine from tests */