Examples with SnapshotRecoverySource org.elasticsearch.cluster.routing.RecoverySource.SnapshotRecoverySource used on opensource projects

Example 16 with SnapshotRecoverySource

use of org.elasticsearch.cluster.routing.RecoverySource.SnapshotRecoverySource in project crate by crate.

the class IndexShard method startRecovery.

public void startRecovery(RecoveryState recoveryState, PeerRecoveryTargetService recoveryTargetService, PeerRecoveryTargetService.RecoveryListener recoveryListener, RepositoriesService repositoriesService, Consumer<MappingMetadata> mappingUpdateConsumer, IndicesService indicesService) {
    // }
    assert recoveryState.getRecoverySource().equals(shardRouting.recoverySource());
    switch(recoveryState.getRecoverySource().getType()) {
        case EMPTY_STORE:
        case EXISTING_STORE:
            executeRecovery("from store", recoveryState, recoveryListener, this::recoverFromStore);
            break;
        case PEER:
            try {
                markAsRecovering("from " + recoveryState.getSourceNode(), recoveryState);
                recoveryTargetService.startRecovery(this, recoveryState.getSourceNode(), recoveryListener);
            } catch (Exception e) {
                failShard("corrupted preexisting index", e);
                recoveryListener.onRecoveryFailure(recoveryState, new RecoveryFailedException(recoveryState, null, e), true);
            }
            break;
        case SNAPSHOT:
            final String repo = ((SnapshotRecoverySource) recoveryState.getRecoverySource()).snapshot().getRepository();
            executeRecovery("from snapshot", recoveryState, recoveryListener, l -> restoreFromRepository(repositoriesService.repository(repo), l));
            break;
        case LOCAL_SHARDS:
            final IndexMetadata indexMetadata = indexSettings().getIndexMetadata();
            final Index resizeSourceIndex = indexMetadata.getResizeSourceIndex();
            final List<IndexShard> startedShards = new ArrayList<>();
            final IndexService sourceIndexService = indicesService.indexService(resizeSourceIndex);
            final Set<ShardId> requiredShards;
            final int numShards;
            if (sourceIndexService != null) {
                requiredShards = IndexMetadata.selectRecoverFromShards(shardId().id(), sourceIndexService.getMetadata(), indexMetadata.getNumberOfShards());
                for (IndexShard shard : sourceIndexService) {
                    if (shard.state() == IndexShardState.STARTED && requiredShards.contains(shard.shardId())) {
                        startedShards.add(shard);
                    }
                }
                numShards = requiredShards.size();
            } else {
                numShards = -1;
                requiredShards = Collections.emptySet();
            }
            if (numShards == startedShards.size()) {
                assert requiredShards.isEmpty() == false;
                executeRecovery("from local shards", recoveryState, recoveryListener, l -> recoverFromLocalShards(mappingUpdateConsumer, startedShards.stream().filter((s) -> requiredShards.contains(s.shardId())).collect(Collectors.toList()), l));
            } else {
                final RuntimeException e;
                if (numShards == -1) {
                    e = new IndexNotFoundException(resizeSourceIndex);
                } else {
                    e = new IllegalStateException("not all required shards of index " + resizeSourceIndex + " are started yet, expected " + numShards + " found " + startedShards.size() + " can't recover shard " + shardId());
                }
                throw e;
            }
            break;
        default:
            throw new IllegalArgumentException("Unknown recovery source " + recoveryState.getRecoverySource());
    }
}

Example 17 with SnapshotRecoverySource

use of org.elasticsearch.cluster.routing.RecoverySource.SnapshotRecoverySource in project crate by crate.

the class RestoreService method restoreSnapshot.

/**
 * Restores snapshot specified in the restore request.
 *
 * @param request  restore request
 * @param listener restore listener
 */
public void restoreSnapshot(final RestoreRequest request, final ActionListener<RestoreCompletionResponse> listener) {
    try {
        // Read snapshot info and metadata from the repository
        final String repositoryName = request.repositoryName;
        Repository repository = repositoriesService.repository(repositoryName);
        final StepListener<RepositoryData> repositoryDataListener = new StepListener<>();
        repository.getRepositoryData(repositoryDataListener);
        repositoryDataListener.whenComplete(repositoryData -> {
            final String snapshotName = request.snapshotName;
            final Optional<SnapshotId> matchingSnapshotId = repositoryData.getSnapshotIds().stream().filter(s -> snapshotName.equals(s.getName())).findFirst();
            if (matchingSnapshotId.isPresent() == false) {
                throw new SnapshotRestoreException(repositoryName, snapshotName, "snapshot does not exist");
            }
            final SnapshotId snapshotId = matchingSnapshotId.get();
            repository.getSnapshotInfo(snapshotId, ActionListener.delegateFailure(listener, (delegate, snapshotInfo) -> {
                final Snapshot snapshot = new Snapshot(repositoryName, snapshotId);
                // Make sure that we can restore from this snapshot
                validateSnapshotRestorable(repositoryName, snapshotInfo);
                // Resolve the indices from the snapshot that need to be restored
                final List<String> indicesInSnapshot = request.includeIndices() ? filterIndices(snapshotInfo.indices(), request.indices(), request.indicesOptions()) : List.of();
                final StepListener<Metadata> globalMetadataListener = new StepListener<>();
                if (request.includeCustomMetadata() || request.includeGlobalSettings() || request.allTemplates() || (request.templates() != null && request.templates().length > 0)) {
                    repository.getSnapshotGlobalMetadata(snapshotId, globalMetadataListener);
                } else {
                    globalMetadataListener.onResponse(Metadata.EMPTY_METADATA);
                }
                globalMetadataListener.whenComplete(globalMetadata -> {
                    var metadataBuilder = Metadata.builder(globalMetadata);
                    var indexIdsInSnapshot = repositoryData.resolveIndices(indicesInSnapshot);
                    var snapshotIndexMetadataListener = new StepListener<Collection<IndexMetadata>>();
                    repository.getSnapshotIndexMetadata(snapshotId, indexIdsInSnapshot, snapshotIndexMetadataListener);
                    snapshotIndexMetadataListener.whenComplete(snapshotIndexMetadata -> {
                        for (IndexMetadata indexMetadata : snapshotIndexMetadata) {
                            metadataBuilder.put(indexMetadata, false);
                        }
                        final Metadata metadata = metadataBuilder.build();
                        // Apply renaming on index names, returning a map of names where
                        // the key is the renamed index and the value is the original name
                        final Map<String, String> indices = renamedIndices(request, indicesInSnapshot);
                        // Now we can start the actual restore process by adding shards to be recovered in the cluster state
                        // and updating cluster metadata (global and index) as needed
                        clusterService.submitStateUpdateTask("restore_snapshot[" + snapshotName + ']', new ClusterStateUpdateTask() {

                            final String restoreUUID = UUIDs.randomBase64UUID();

                            RestoreInfo restoreInfo = null;

                            @Override
                            public ClusterState execute(ClusterState currentState) {
                                RestoreInProgress restoreInProgress = currentState.custom(RestoreInProgress.TYPE);
                                // Check if the snapshot to restore is currently being deleted
                                SnapshotDeletionsInProgress deletionsInProgress = currentState.custom(SnapshotDeletionsInProgress.TYPE);
                                if (deletionsInProgress != null && deletionsInProgress.getEntries().stream().anyMatch(entry -> entry.getSnapshot().equals(snapshot))) {
                                    throw new ConcurrentSnapshotExecutionException(snapshot, "cannot restore a snapshot while a snapshot deletion is in-progress [" + deletionsInProgress.getEntries().get(0).getSnapshot() + "]");
                                }
                                // Updating cluster state
                                ClusterState.Builder builder = ClusterState.builder(currentState);
                                Metadata.Builder mdBuilder = Metadata.builder(currentState.metadata());
                                ClusterBlocks.Builder blocks = ClusterBlocks.builder().blocks(currentState.blocks());
                                RoutingTable.Builder rtBuilder = RoutingTable.builder(currentState.routingTable());
                                ImmutableOpenMap<ShardId, RestoreInProgress.ShardRestoreStatus> shards;
                                Set<String> aliases = new HashSet<>();
                                if (indices.isEmpty() == false) {
                                    // We have some indices to restore
                                    ImmutableOpenMap.Builder<ShardId, RestoreInProgress.ShardRestoreStatus> shardsBuilder = ImmutableOpenMap.builder();
                                    final Version minIndexCompatibilityVersion = currentState.getNodes().getMaxNodeVersion().minimumIndexCompatibilityVersion();
                                    for (Map.Entry<String, String> indexEntry : indices.entrySet()) {
                                        String index = indexEntry.getValue();
                                        boolean partial = checkPartial(index);
                                        SnapshotRecoverySource recoverySource = new SnapshotRecoverySource(restoreUUID, snapshot, snapshotInfo.version(), index);
                                        String renamedIndexName = indexEntry.getKey();
                                        IndexMetadata snapshotIndexMetadata = metadata.index(index);
                                        snapshotIndexMetadata = updateIndexSettings(snapshotIndexMetadata, request.indexSettings(), request.ignoreIndexSettings());
                                        try {
                                            snapshotIndexMetadata = metadataIndexUpgradeService.upgradeIndexMetadata(snapshotIndexMetadata, minIndexCompatibilityVersion);
                                        } catch (Exception ex) {
                                            throw new SnapshotRestoreException(snapshot, "cannot restore index [" + index + "] because it cannot be upgraded", ex);
                                        }
                                        // Check that the index is closed or doesn't exist
                                        IndexMetadata currentIndexMetadata = currentState.metadata().index(renamedIndexName);
                                        IntSet ignoreShards = new IntHashSet();
                                        final Index renamedIndex;
                                        if (currentIndexMetadata == null) {
                                            // Index doesn't exist - create it and start recovery
                                            // Make sure that the index we are about to create has a validate name
                                            MetadataCreateIndexService.validateIndexName(renamedIndexName, currentState);
                                            createIndexService.validateIndexSettings(renamedIndexName, snapshotIndexMetadata.getSettings(), currentState, false);
                                            IndexMetadata.Builder indexMdBuilder = IndexMetadata.builder(snapshotIndexMetadata).state(IndexMetadata.State.OPEN).index(renamedIndexName);
                                            indexMdBuilder.settings(Settings.builder().put(snapshotIndexMetadata.getSettings()).put(IndexMetadata.SETTING_INDEX_UUID, UUIDs.randomBase64UUID()));
                                            shardLimitValidator.validateShardLimit(snapshotIndexMetadata.getSettings(), currentState);
                                            if (!request.includeAliases() && !snapshotIndexMetadata.getAliases().isEmpty()) {
                                                // Remove all aliases - they shouldn't be restored
                                                indexMdBuilder.removeAllAliases();
                                            } else {
                                                for (ObjectCursor<String> alias : snapshotIndexMetadata.getAliases().keys()) {
                                                    aliases.add(alias.value);
                                                }
                                            }
                                            IndexMetadata updatedIndexMetadata = indexMdBuilder.build();
                                            if (partial) {
                                                populateIgnoredShards(index, ignoreShards);
                                            }
                                            rtBuilder.addAsNewRestore(updatedIndexMetadata, recoverySource, ignoreShards);
                                            blocks.addBlocks(updatedIndexMetadata);
                                            mdBuilder.put(updatedIndexMetadata, true);
                                            renamedIndex = updatedIndexMetadata.getIndex();
                                        } else {
                                            validateExistingIndex(currentIndexMetadata, snapshotIndexMetadata, renamedIndexName, partial);
                                            // Index exists and it's closed - open it in metadata and start recovery
                                            IndexMetadata.Builder indexMdBuilder = IndexMetadata.builder(snapshotIndexMetadata).state(IndexMetadata.State.OPEN);
                                            indexMdBuilder.version(Math.max(snapshotIndexMetadata.getVersion(), 1 + currentIndexMetadata.getVersion()));
                                            indexMdBuilder.mappingVersion(Math.max(snapshotIndexMetadata.getMappingVersion(), 1 + currentIndexMetadata.getMappingVersion()));
                                            indexMdBuilder.settingsVersion(Math.max(snapshotIndexMetadata.getSettingsVersion(), 1 + currentIndexMetadata.getSettingsVersion()));
                                            for (int shard = 0; shard < snapshotIndexMetadata.getNumberOfShards(); shard++) {
                                                indexMdBuilder.primaryTerm(shard, Math.max(snapshotIndexMetadata.primaryTerm(shard), currentIndexMetadata.primaryTerm(shard)));
                                            }
                                            if (!request.includeAliases()) {
                                                // Remove all snapshot aliases
                                                if (!snapshotIndexMetadata.getAliases().isEmpty()) {
                                                    indexMdBuilder.removeAllAliases();
                                                }
                                                // Add existing aliases
                                                for (ObjectCursor<AliasMetadata> alias : currentIndexMetadata.getAliases().values()) {
                                                    indexMdBuilder.putAlias(alias.value);
                                                }
                                            } else {
                                                for (ObjectCursor<String> alias : snapshotIndexMetadata.getAliases().keys()) {
                                                    aliases.add(alias.value);
                                                }
                                            }
                                            indexMdBuilder.settings(Settings.builder().put(snapshotIndexMetadata.getSettings()).put(IndexMetadata.SETTING_INDEX_UUID, currentIndexMetadata.getIndexUUID()));
                                            IndexMetadata updatedIndexMetadata = indexMdBuilder.index(renamedIndexName).build();
                                            rtBuilder.addAsRestore(updatedIndexMetadata, recoverySource);
                                            blocks.updateBlocks(updatedIndexMetadata);
                                            mdBuilder.put(updatedIndexMetadata, true);
                                            renamedIndex = updatedIndexMetadata.getIndex();
                                        }
                                        for (int shard = 0; shard < snapshotIndexMetadata.getNumberOfShards(); shard++) {
                                            if (!ignoreShards.contains(shard)) {
                                                shardsBuilder.put(new ShardId(renamedIndex, shard), new RestoreInProgress.ShardRestoreStatus(clusterService.state().nodes().getLocalNodeId()));
                                            } else {
                                                shardsBuilder.put(new ShardId(renamedIndex, shard), new RestoreInProgress.ShardRestoreStatus(clusterService.state().nodes().getLocalNodeId(), RestoreInProgress.State.FAILURE));
                                            }
                                        }
                                    }
                                    shards = shardsBuilder.build();
                                    RestoreInProgress.Entry restoreEntry = new RestoreInProgress.Entry(restoreUUID, snapshot, overallState(RestoreInProgress.State.INIT, shards), List.copyOf(indices.keySet()), shards);
                                    RestoreInProgress.Builder restoreInProgressBuilder;
                                    if (restoreInProgress != null) {
                                        restoreInProgressBuilder = new RestoreInProgress.Builder(restoreInProgress);
                                    } else {
                                        restoreInProgressBuilder = new RestoreInProgress.Builder();
                                    }
                                    builder.putCustom(RestoreInProgress.TYPE, restoreInProgressBuilder.add(restoreEntry).build());
                                } else {
                                    shards = ImmutableOpenMap.of();
                                }
                                validateExistingTemplates();
                                checkAliasNameConflicts(indices, aliases);
                                // Restore templates (but do NOT overwrite existing templates)
                                restoreTemplates(mdBuilder, currentState);
                                // Restore global state if needed
                                if (request.includeGlobalSettings() && metadata.persistentSettings() != null) {
                                    Settings settings = metadata.persistentSettings();
                                    // CrateDB patch to only restore defined settings
                                    if (request.globalSettings().length > 0) {
                                        var filteredSettingBuilder = Settings.builder();
                                        for (String prefix : request.globalSettings()) {
                                            filteredSettingBuilder.put(settings.filter(s -> s.startsWith(prefix)));
                                        }
                                        settings = filteredSettingBuilder.build();
                                    }
                                    clusterSettings.validateUpdate(settings);
                                    mdBuilder.persistentSettings(settings);
                                }
                                if (request.includeCustomMetadata() && metadata.customs() != null) {
                                    // CrateDB patch to only restore defined custom metadata types
                                    List<String> customMetadataTypes = Arrays.asList(request.customMetadataTypes());
                                    boolean includeAll = customMetadataTypes.size() == 0;
                                    for (ObjectObjectCursor<String, Metadata.Custom> cursor : metadata.customs()) {
                                        if (!RepositoriesMetadata.TYPE.equals(cursor.key)) {
                                            if (includeAll || customMetadataTypes.contains(cursor.key)) {
                                                mdBuilder.putCustom(cursor.key, cursor.value);
                                            }
                                        }
                                    }
                                }
                                if (completed(shards)) {
                                    // We don't have any indices to restore - we are done
                                    restoreInfo = new RestoreInfo(snapshotId.getName(), Collections.unmodifiableList(new ArrayList<>(indices.keySet())), shards.size(), shards.size() - failedShards(shards));
                                }
                                RoutingTable rt = rtBuilder.build();
                                ClusterState updatedState = builder.metadata(mdBuilder).blocks(blocks).routingTable(rt).build();
                                return allocationService.reroute(updatedState, "restored snapshot [" + snapshot + "]");
                            }

                            private void checkAliasNameConflicts(Map<String, String> renamedIndices, Set<String> aliases) {
                                for (Map.Entry<String, String> renamedIndex : renamedIndices.entrySet()) {
                                    if (aliases.contains(renamedIndex.getKey())) {
                                        throw new SnapshotRestoreException(snapshot, "cannot rename index [" + renamedIndex.getValue() + "] into [" + renamedIndex.getKey() + "] because of conflict with an alias with the same name");
                                    }
                                }
                            }

                            private void populateIgnoredShards(String index, IntSet ignoreShards) {
                                for (SnapshotShardFailure failure : snapshotInfo.shardFailures()) {
                                    if (index.equals(failure.index())) {
                                        ignoreShards.add(failure.shardId());
                                    }
                                }
                            }

                            private boolean checkPartial(String index) {
                                // Make sure that index was fully snapshotted
                                if (failed(snapshotInfo, index)) {
                                    if (request.partial()) {
                                        return true;
                                    } else {
                                        throw new SnapshotRestoreException(snapshot, "index [" + index + "] wasn't fully snapshotted - cannot " + "restore");
                                    }
                                } else {
                                    return false;
                                }
                            }

                            private void validateExistingIndex(IndexMetadata currentIndexMetadata, IndexMetadata snapshotIndexMetadata, String renamedIndex, boolean partial) {
                                // Index exist - checking that it's closed
                                if (currentIndexMetadata.getState() != IndexMetadata.State.CLOSE) {
                                    // TODO: Enable restore for open indices
                                    throw new SnapshotRestoreException(snapshot, "cannot restore index [" + renamedIndex + "] because an open index " + "with same name already exists in the cluster. Either close or delete the existing index or restore the " + "index under a different name by providing a rename pattern and replacement name");
                                }
                                // Index exist - checking if it's partial restore
                                if (partial) {
                                    throw new SnapshotRestoreException(snapshot, "cannot restore partial index [" + renamedIndex + "] because such index already exists");
                                }
                                // Make sure that the number of shards is the same. That's the only thing that we cannot change
                                if (currentIndexMetadata.getNumberOfShards() != snapshotIndexMetadata.getNumberOfShards()) {
                                    throw new SnapshotRestoreException(snapshot, "cannot restore index [" + renamedIndex + "] with [" + currentIndexMetadata.getNumberOfShards() + "] shards from a snapshot of index [" + snapshotIndexMetadata.getIndex().getName() + "] with [" + snapshotIndexMetadata.getNumberOfShards() + "] shards");
                                }
                            }

                            /**
                             * Optionally updates index settings in indexMetadata by removing settings listed in ignoreSettings and
                             * merging them with settings in changeSettings.
                             */
                            private IndexMetadata updateIndexSettings(IndexMetadata indexMetadata, Settings changeSettings, String[] ignoreSettings) {
                                if (changeSettings.names().isEmpty() && ignoreSettings.length == 0) {
                                    return indexMetadata;
                                }
                                Settings normalizedChangeSettings = Settings.builder().put(changeSettings).normalizePrefix(IndexMetadata.INDEX_SETTING_PREFIX).build();
                                IndexMetadata.Builder builder = IndexMetadata.builder(indexMetadata);
                                Settings settings = indexMetadata.getSettings();
                                Set<String> keyFilters = new HashSet<>();
                                List<String> simpleMatchPatterns = new ArrayList<>();
                                for (String ignoredSetting : ignoreSettings) {
                                    if (!Regex.isSimpleMatchPattern(ignoredSetting)) {
                                        if (UNREMOVABLE_SETTINGS.contains(ignoredSetting)) {
                                            throw new SnapshotRestoreException(snapshot, "cannot remove setting [" + ignoredSetting + "] on restore");
                                        } else {
                                            keyFilters.add(ignoredSetting);
                                        }
                                    } else {
                                        simpleMatchPatterns.add(ignoredSetting);
                                    }
                                }
                                Predicate<String> settingsFilter = k -> {
                                    if (UNREMOVABLE_SETTINGS.contains(k) == false) {
                                        for (String filterKey : keyFilters) {
                                            if (k.equals(filterKey)) {
                                                return false;
                                            }
                                        }
                                        for (String pattern : simpleMatchPatterns) {
                                            if (Regex.simpleMatch(pattern, k)) {
                                                return false;
                                            }
                                        }
                                    }
                                    return true;
                                };
                                Settings.Builder settingsBuilder = Settings.builder().put(settings.filter(settingsFilter)).put(normalizedChangeSettings.filter(k -> {
                                    if (UNMODIFIABLE_SETTINGS.contains(k)) {
                                        throw new SnapshotRestoreException(snapshot, "cannot modify setting [" + k + "] on restore");
                                    } else {
                                        return true;
                                    }
                                }));
                                settingsBuilder.remove(IndexMetadata.VERIFIED_BEFORE_CLOSE_SETTING.getKey());
                                return builder.settings(settingsBuilder).build();
                            }

                            private void restoreTemplates(Metadata.Builder mdBuilder, ClusterState currentState) {
                                List<String> toRestore = Arrays.asList(request.templates());
                                if (metadata.templates() != null) {
                                    for (ObjectCursor<IndexTemplateMetadata> cursor : metadata.templates().values()) {
                                        if (currentState.metadata().templates().get(cursor.value.name()) == null && (request.allTemplates() || toRestore.contains(cursor.value.name()))) {
                                            mdBuilder.put(cursor.value);
                                        }
                                    }
                                }
                            }

                            private void validateExistingTemplates() {
                                if (request.indicesOptions().ignoreUnavailable() || request.allTemplates()) {
                                    return;
                                }
                                for (String template : request.templates()) {
                                    if (!metadata.templates().containsKey(template)) {
                                        throw new ResourceNotFoundException("[{}] template not found", template);
                                    }
                                }
                            }

                            @Override
                            public void onFailure(String source, Exception e) {
                                LOGGER.warn(() -> new ParameterizedMessage("[{}] failed to restore snapshot", snapshotId), e);
                                listener.onFailure(e);
                            }

                            @Override
                            public TimeValue timeout() {
                                return request.masterNodeTimeout();
                            }

                            @Override
                            public void clusterStateProcessed(String source, ClusterState oldState, ClusterState newState) {
                                listener.onResponse(new RestoreCompletionResponse(restoreUUID, snapshot, restoreInfo));
                            }
                        });
                    }, listener::onFailure);
                }, listener::onFailure);
            }));
        }, listener::onFailure);
    } catch (Exception e) {
        LOGGER.warn(() -> new ParameterizedMessage("[{}] failed to restore snapshot", request.repositoryName + ":" + request.snapshotName), e);
        listener.onFailure(e);
    }
}

Example 18 with SnapshotRecoverySource

use of org.elasticsearch.cluster.routing.RecoverySource.SnapshotRecoverySource in project crate by crate.

the class NodeVersionAllocationDeciderTests method testMessages.

public void testMessages() {
    Metadata metadata = Metadata.builder().put(IndexMetadata.builder("test").settings(settings(Version.CURRENT)).numberOfShards(1).numberOfReplicas(1)).build();
    RoutingTable initialRoutingTable = RoutingTable.builder().addAsNew(metadata.index("test")).build();
    RoutingNode newNode = new RoutingNode("newNode", newNode("newNode", Version.CURRENT));
    RoutingNode oldNode = new RoutingNode("oldNode", newNode("oldNode", VersionUtils.getPreviousVersion()));
    final ClusterName clusterName = ClusterName.CLUSTER_NAME_SETTING.getDefault(Settings.EMPTY);
    ClusterState clusterState = ClusterState.builder(clusterName).metadata(metadata).routingTable(initialRoutingTable).nodes(DiscoveryNodes.builder().add(newNode.node()).add(oldNode.node())).build();
    final ShardId shardId = clusterState.routingTable().index("test").shard(0).getShardId();
    final ShardRouting primaryShard = clusterState.routingTable().shardRoutingTable(shardId).primaryShard();
    final ShardRouting replicaShard = clusterState.routingTable().shardRoutingTable(shardId).replicaShards().get(0);
    RoutingAllocation routingAllocation = new RoutingAllocation(null, clusterState.getRoutingNodes(), clusterState, null, 0);
    routingAllocation.debugDecision(true);
    final NodeVersionAllocationDecider allocationDecider = new NodeVersionAllocationDecider();
    Decision decision = allocationDecider.canAllocate(primaryShard, newNode, routingAllocation);
    assertThat(decision.type(), is(Decision.Type.YES));
    assertThat(decision.getExplanation(), is("the primary shard is new or already existed on the node"));
    decision = allocationDecider.canAllocate(ShardRoutingHelper.initialize(primaryShard, "oldNode"), newNode, routingAllocation);
    assertThat(decision.type(), is(Decision.Type.YES));
    assertThat(decision.getExplanation(), is("can relocate primary shard from a node with version [" + oldNode.node().getVersion() + "] to a node with equal-or-newer version [" + newNode.node().getVersion() + "]"));
    decision = allocationDecider.canAllocate(ShardRoutingHelper.initialize(primaryShard, "newNode"), oldNode, routingAllocation);
    assertThat(decision.type(), is(Decision.Type.NO));
    assertThat(decision.getExplanation(), is("cannot relocate primary shard from a node with version [" + newNode.node().getVersion() + "] to a node with older version [" + oldNode.node().getVersion() + "]"));
    final SnapshotRecoverySource newVersionSnapshot = new SnapshotRecoverySource(UUIDs.randomBase64UUID(), new Snapshot("rep1", new SnapshotId("snp1", UUIDs.randomBase64UUID())), newNode.node().getVersion(), "test");
    final SnapshotRecoverySource oldVersionSnapshot = new SnapshotRecoverySource(UUIDs.randomBase64UUID(), new Snapshot("rep1", new SnapshotId("snp1", UUIDs.randomBase64UUID())), oldNode.node().getVersion(), "test");
    decision = allocationDecider.canAllocate(ShardRoutingHelper.newWithRestoreSource(primaryShard, newVersionSnapshot), oldNode, routingAllocation);
    assertThat(decision.type(), is(Decision.Type.NO));
    assertThat(decision.getExplanation(), is("node version [" + oldNode.node().getVersion() + "] is older than the snapshot version [" + newNode.node().getVersion() + "]"));
    decision = allocationDecider.canAllocate(ShardRoutingHelper.newWithRestoreSource(primaryShard, oldVersionSnapshot), newNode, routingAllocation);
    assertThat(decision.type(), is(Decision.Type.YES));
    assertThat(decision.getExplanation(), is("node version [" + newNode.node().getVersion() + "] is the same or newer than snapshot version [" + oldNode.node().getVersion() + "]"));
    final RoutingChangesObserver routingChangesObserver = new RoutingChangesObserver.AbstractRoutingChangesObserver();
    final RoutingNodes routingNodes = new RoutingNodes(clusterState, false);
    final ShardRouting startedPrimary = routingNodes.startShard(logger, routingNodes.initializeShard(primaryShard, "newNode", null, 0, routingChangesObserver), routingChangesObserver);
    routingAllocation = new RoutingAllocation(null, routingNodes, clusterState, null, 0);
    routingAllocation.debugDecision(true);
    decision = allocationDecider.canAllocate(replicaShard, oldNode, routingAllocation);
    assertThat(decision.type(), is(Decision.Type.NO));
    assertThat(decision.getExplanation(), is("cannot allocate replica shard to a node with version [" + oldNode.node().getVersion() + "] since this is older than the primary version [" + newNode.node().getVersion() + "]"));
    routingNodes.startShard(logger, routingNodes.relocateShard(startedPrimary, "oldNode", 0, routingChangesObserver).v2(), routingChangesObserver);
    routingAllocation = new RoutingAllocation(null, routingNodes, clusterState, null, 0);
    routingAllocation.debugDecision(true);
    decision = allocationDecider.canAllocate(replicaShard, newNode, routingAllocation);
    assertThat(decision.type(), is(Decision.Type.YES));
    assertThat(decision.getExplanation(), is("can allocate replica shard to a node with version [" + newNode.node().getVersion() + "] since this is equal-or-newer than the primary version [" + oldNode.node().getVersion() + "]"));
}