Allow some Repository Settings to be Updated Dynamically (#72543)

This commit serves two purposes. For one, we need the ability to dynamically
update a repository setting for the encrypted repository work.

Also, this allows dynamically updating repository rate limits while snapshots are
in progress. This has often been an issue in the past where a long running snapshot
made progress over a long period of time already but is going too slowly with the
current rate limit. This left no good options, either throw away the existing
partly done snapshot's work and recreate the repo with a higher rate limit to speed
things up or wait for a long time with the current rate limit.
With this change the rate limit can simply be increased while a snapshot or restore
is running and will take effect imidiately.

server/src/internalClusterTest/java/org/elasticsearch/repositories/blobstore/BlobStoreDynamicSettingsIT.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+package org.elasticsearch.repositories.blobstore;
+
+import org.elasticsearch.ExceptionsHelper;
+import org.elasticsearch.action.ActionFuture;
+import org.elasticsearch.action.admin.cluster.snapshots.create.CreateSnapshotResponse;
+import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.unit.ByteSizeValue;
+import org.elasticsearch.repositories.Repository;
+import org.elasticsearch.snapshots.AbstractSnapshotIntegTestCase;
+import org.elasticsearch.snapshots.mockstore.MockRepository;
+import org.elasticsearch.test.ESIntegTestCase;
+
+import static org.hamcrest.Matchers.instanceOf;
+
+@ESIntegTestCase.ClusterScope(scope = ESIntegTestCase.Scope.TEST, numDataNodes = 0)
+public class BlobStoreDynamicSettingsIT extends AbstractSnapshotIntegTestCase {
+
+    public void testUpdateRateLimitsDynamically() throws Exception {
+        final String masterNode = internalCluster().startMasterOnlyNode();
+
+        final boolean largeSnapshotPool = randomBoolean();
+        final String dataNode;
+        if (largeSnapshotPool) {
+            dataNode = startDataNodeWithLargeSnapshotPool();
+        } else {
+            dataNode = internalCluster().startDataOnlyNode();
+        }
+
+        final String repoName = "test-repo";
+        // use a small chunk size so the rate limiter does not overshoot to far and get blocked a very long time below
+        createRepository(repoName, "mock", randomRepositorySettings().put("chunk_size", "100b"));
+
+        if (randomBoolean()) {
+            createFullSnapshot(repoName, "snapshot-1");
+        }
+
+        final String indexName = "test-idx";
+        createIndexWithContent(indexName);
+
+        final Repository repoOnMaster = getRepositoryOnNode(repoName, masterNode);
+        final Repository repoOnDataNode = getRepositoryOnNode(repoName, dataNode);
+
+        final Settings currentSettings = repoOnMaster.getMetadata().settings();
+        assertNull(currentSettings.get(BlobStoreRepository.MAX_SNAPSHOT_BYTES_PER_SEC.getKey()));
+        assertNull(currentSettings.get(BlobStoreRepository.MAX_RESTORE_BYTES_PER_SEC.getKey()));
+
+        createRepository(
+                repoName,
+                "mock",
+                Settings.builder().put(currentSettings).put(BlobStoreRepository.MAX_SNAPSHOT_BYTES_PER_SEC.getKey(), "1b"),
+                randomBoolean()
+        );
+
+        assertSame(repoOnMaster, getRepositoryOnNode(repoName, masterNode));
+        assertSame(repoOnDataNode, getRepositoryOnNode(repoName, dataNode));
+
+        final Settings updatedSettings = repoOnMaster.getMetadata().settings();
+        assertEquals(ByteSizeValue.ofBytes(1L),
+                updatedSettings.getAsBytesSize(BlobStoreRepository.MAX_SNAPSHOT_BYTES_PER_SEC.getKey(), ByteSizeValue.ZERO));
+        assertNull(currentSettings.get(BlobStoreRepository.MAX_RESTORE_BYTES_PER_SEC.getKey()));
+
+        final ActionFuture<CreateSnapshotResponse> snapshot1 = startFullSnapshotBlockedOnDataNode("snapshot-2", repoName, dataNode);
+
+        // we only run concurrent verification when we have a large SNAPSHOT pool on the data node because otherwise the verification would
+        // deadlock since the small pool is already blocked by the snapshot on the data node
+        createRepository(
+                repoName,
+                "mock",
+                Settings.builder().put(updatedSettings).put(BlobStoreRepository.MAX_SNAPSHOT_BYTES_PER_SEC.getKey(), "1024b"),
+                largeSnapshotPool && randomBoolean()
+        );
+        assertSame(repoOnMaster, getRepositoryOnNode(repoName, masterNode));
+        assertSame(repoOnDataNode, getRepositoryOnNode(repoName, dataNode));
+
+        logger.info("--> verify that we can't update [location] dynamically");
+        try {
+            // this setting update will fail so we can set the verification parameter randomly even if the SNAPSHOT pool is already blocked
+            // since we will never actually get to the verification step
+            createRepository(
+                    repoName,
+                    "mock",
+                    Settings.builder().put(repoOnMaster.getMetadata().settings()).put("location", randomRepoPath()),
+                    randomBoolean()
+            );
+        } catch (Exception e) {
+            final Throwable ise = ExceptionsHelper.unwrap(e, IllegalStateException.class);
+            assertThat(ise, instanceOf(IllegalStateException.class));
+            assertEquals(ise.getMessage(), "trying to modify or unregister repository that is currently used");
+        }
+
+        logger.info("--> verify that we can update [{}] dynamically", MockRepository.DUMMY_UPDATABLE_SETTING_NAME);
+        final String dummySettingValue = randomUnicodeOfCodepointLength(10);
+        // we only run concurrent verification when we have a large SNAPSHOT pool on the data node because otherwise the verification would
+        // deadlock since the small pool is already blocked by the snapshot on the data node
+        createRepository(
+                repoName,
+                "mock",
+                Settings.builder().put(repoOnMaster.getMetadata().settings())
+                        .put(MockRepository.DUMMY_UPDATABLE_SETTING_NAME, dummySettingValue),
+                largeSnapshotPool && randomBoolean()
+        );
+        final Repository newRepoOnMaster = getRepositoryOnNode(repoName, masterNode);
+        assertSame(repoOnMaster, newRepoOnMaster);
+        assertSame(repoOnDataNode, getRepositoryOnNode(repoName, dataNode));
+        assertEquals(dummySettingValue, newRepoOnMaster.getMetadata().settings().get(MockRepository.DUMMY_UPDATABLE_SETTING_NAME));
+
+        unblockNode(repoName, dataNode);
+        assertSuccessful(snapshot1);
+    }
+}

server/src/internalClusterTest/java/org/elasticsearch/snapshots/ConcurrentSnapshotsIT.java

@@ -1259,10 +1259,6 @@ public class ConcurrentSnapshotsIT extends AbstractSnapshotIntegTestCase {
         assertSuccessful(otherSnapshot);
     }
 
-    private static String startDataNodeWithLargeSnapshotPool() {
-        return internalCluster().startDataOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
-    }
-
     private static void assertSnapshotStatusCountOnRepo(String otherBlockedRepoName, int count) {
         final SnapshotsStatusResponse snapshotsStatusResponse =
             client().admin().cluster().prepareSnapshotStatus(otherBlockedRepoName).get();

server/src/main/java/org/elasticsearch/cluster/metadata/RepositoryMetadata.java

@@ -196,4 +196,8 @@ public class RepositoryMetadata implements Writeable {
     public RepositoryMetadata withUuid(String uuid) {
         return new RepositoryMetadata(name, uuid, type, settings, generation, pendingGeneration);
     }
+
+    public RepositoryMetadata withSettings(Settings settings) {
+        return new RepositoryMetadata(name, uuid, type, settings, generation, pendingGeneration);
+    }
 }

server/src/main/java/org/elasticsearch/repositories/FilterRepository.java

@@ -17,6 +17,7 @@ import org.elasticsearch.cluster.metadata.RepositoryMetadata;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.component.Lifecycle;
 import org.elasticsearch.common.component.LifecycleListener;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.index.snapshots.IndexShardSnapshotStatus;
 import org.elasticsearch.index.store.Store;
@@ -26,6 +27,7 @@ import org.elasticsearch.snapshots.SnapshotInfo;
 
 import java.io.IOException;
 import java.util.Collection;
+import java.util.Set;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
@@ -125,6 +127,11 @@ public class FilterRepository implements Repository {
         return in.getShardSnapshotStatus(snapshotId, indexId, shardId);
     }
 
+    @Override
+    public boolean canUpdateInPlace(Settings updatedSettings, Set<String> ignoredSettings) {
+        return in.canUpdateInPlace(updatedSettings, ignoredSettings);
+    }
+
     @Override
     public void updateState(ClusterState state) {
         in.updateState(state);

server/src/main/java/org/elasticsearch/repositories/RepositoriesService.java

@@ -173,7 +173,6 @@ public class RepositoriesService extends AbstractLifecycleComponent implements C
 
                 @Override
                 public ClusterState execute(ClusterState currentState) {
-                    ensureRepositoryNotInUse(currentState, request.name());
                     Metadata metadata = currentState.metadata();
                     Metadata.Builder mdBuilder = Metadata.builder(currentState.metadata());
                     RepositoriesMetadata repositories = metadata.custom(RepositoriesMetadata.TYPE, RepositoriesMetadata.EMPTY);
@@ -184,8 +183,22 @@ public class RepositoriesService extends AbstractLifecycleComponent implements C
                                 // Previous version is the same as this one no update is needed.
                                 return currentState;
                             }
+                            Repository existing = RepositoriesService.this.repositories.get(request.name());
+                            if (existing == null) {
+                                existing = RepositoriesService.this.internalRepositories.get(request.name());
+                            }
+                            assert existing != null : "repository [" + newRepositoryMetadata.name() + "] must exist";
+                            assert existing.getMetadata() == repositoryMetadata;
+                            final RepositoryMetadata updatedMetadata;
+                            if (canUpdateInPlace(newRepositoryMetadata, existing)) {
+                                // we're updating in place so the updated metadata must point at the same uuid and generations
+                                updatedMetadata = repositoryMetadata.withSettings(newRepositoryMetadata.settings());
+                            } else {
+                                ensureRepositoryNotInUse(currentState, request.name());
+                                updatedMetadata = newRepositoryMetadata;
+                            }
                             found = true;
-                            repositoriesMetadata.add(newRepositoryMetadata);
+                            repositoriesMetadata.add(updatedMetadata);
                         } else {
                             repositoriesMetadata.add(repositoryMetadata);
                         }
@@ -430,9 +443,7 @@ public class RepositoriesService extends AbstractLifecycleComponent implements C
                 Repository repository = survivors.get(repositoryMetadata.name());
                 if (repository != null) {
                     // Found previous version of this repository
-                    RepositoryMetadata previousMetadata = repository.getMetadata();
-                    if (previousMetadata.type().equals(repositoryMetadata.type()) == false
-                            || previousMetadata.settings().equals(repositoryMetadata.settings()) == false) {
+                    if (canUpdateInPlace(repositoryMetadata, repository) == false) {
                         // Previous version is different from the version in settings
                         logger.debug("updating repository [{}]", repositoryMetadata.name());
                         closeRepository(repository);
@@ -469,6 +480,12 @@ public class RepositoriesService extends AbstractLifecycleComponent implements C
         }
     }
 
+    private boolean canUpdateInPlace(RepositoryMetadata updatedMetadata, Repository repository) {
+        assert updatedMetadata.name().equals(repository.getMetadata().name());
+        return repository.getMetadata().type().equals(updatedMetadata.type())
+                && repository.canUpdateInPlace(updatedMetadata.settings(), Collections.emptySet());
+    }
+
     /**
      * Gets the {@link RepositoryData} for the given repository.
      *

server/src/main/java/org/elasticsearch/repositories/Repository.java

@@ -18,6 +18,7 @@ import org.elasticsearch.cluster.metadata.RepositoryMetadata;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.common.Nullable;
 import org.elasticsearch.common.component.LifecycleComponent;
+import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.index.snapshots.IndexShardSnapshotStatus;
 import org.elasticsearch.index.store.Store;
@@ -28,6 +29,7 @@ import org.elasticsearch.snapshots.SnapshotInfo;
 import java.io.IOException;
 import java.util.Collection;
 import java.util.Map;
+import java.util.Set;
 import java.util.function.Consumer;
 import java.util.function.Function;
 
@@ -214,6 +216,17 @@ public interface Repository extends LifecycleComponent {
      */
     IndexShardSnapshotStatus getShardSnapshotStatus(SnapshotId snapshotId, IndexId indexId, ShardId shardId);
 
+    /**
+     * Check if this instances {@link Settings} can be changed to the provided updated settings without recreating the repository.
+     *
+     * @param updatedSettings new repository settings
+     * @param ignoredSettings setting names to ignore even if changed
+     * @return true if the repository can be updated in place
+     */
+    default boolean canUpdateInPlace(Settings updatedSettings, Set<String> ignoredSettings) {
+        return getMetadata().settings().equals(updatedSettings);
+    }
+
     /**
      * Update the repository with the incoming cluster state. This method is invoked from {@link RepositoriesService#applyClusterState} and
      * thus the same semantics as with {@link org.elasticsearch.cluster.ClusterStateApplier#applyClusterState} apply for the

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

@@ -121,9 +121,11 @@ import java.nio.file.NoSuchFileException;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 import java.util.concurrent.BlockingQueue;
@@ -234,9 +236,9 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
 
     private final boolean cacheRepositoryData;
 
-    private final RateLimiter snapshotRateLimiter;
+    private volatile RateLimiter snapshotRateLimiter;
 
-    private final RateLimiter restoreRateLimiter;
+    private volatile RateLimiter restoreRateLimiter;
 
     private final CounterMetric snapshotRateLimitingTimeInNanos = new CounterMetric();
 
@@ -259,6 +261,18 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
     public static final ChecksumBlobStoreFormat<BlobStoreIndexShardSnapshots> INDEX_SHARD_SNAPSHOTS_FORMAT =
             new ChecksumBlobStoreFormat<>("snapshots", SNAPSHOT_INDEX_NAME_FORMAT, BlobStoreIndexShardSnapshots::fromXContent);
 
+    public static final Setting<ByteSizeValue> MAX_SNAPSHOT_BYTES_PER_SEC = Setting.byteSizeSetting("max_snapshot_bytes_per_sec",
+            new ByteSizeValue(40, ByteSizeUnit.MB), Setting.Property.Dynamic, Setting.Property.NodeScope);
+
+    public static final Setting<ByteSizeValue> MAX_RESTORE_BYTES_PER_SEC = Setting.byteSizeSetting("max_restore_bytes_per_sec",
+            ByteSizeValue.ZERO, Setting.Property.Dynamic, Setting.Property.NodeScope);
+
+    /**
+     * Repository settings that can be updated dynamically without having to create a new repository.
+     */
+    private static final Set<String> DYNAMIC_SETTING_NAMES =
+            Set.of(MAX_SNAPSHOT_BYTES_PER_SEC.getKey(), MAX_RESTORE_BYTES_PER_SEC.getKey());
+
     private final boolean readOnly;
 
     private final Object lock = new Object();
@@ -331,8 +345,8 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
         this.recoverySettings = recoverySettings;
         this.compress = COMPRESS_SETTING.get(metadata.settings());
         this.supportURLRepo = SUPPORT_URL_REPO.get(metadata.settings());
-        snapshotRateLimiter = getRateLimiter(metadata.settings(), "max_snapshot_bytes_per_sec", new ByteSizeValue(40, ByteSizeUnit.MB));
-        restoreRateLimiter = getRateLimiter(metadata.settings(), "max_restore_bytes_per_sec", ByteSizeValue.ZERO);
+        snapshotRateLimiter = getRateLimiter(metadata.settings(), MAX_SNAPSHOT_BYTES_PER_SEC);
+        restoreRateLimiter = getRateLimiter(metadata.settings(), MAX_RESTORE_BYTES_PER_SEC);
         readOnly = metadata.settings().getAsBoolean(READONLY_SETTING_KEY, false);
         cacheRepositoryData = CACHE_REPOSITORY_DATA.get(metadata.settings());
         bufferSize = Math.toIntExact(BUFFER_SIZE_SETTING.get(metadata.settings()).getBytes());
@@ -490,11 +504,32 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
         return Math.toIntExact(Math.min(Integer.MAX_VALUE, indexFiles.stream().filter(fi -> fi.physicalName().endsWith(".si")).count()));
     }
 
+    @Override
+    public boolean canUpdateInPlace(Settings updatedSettings, Set<String> ignoredSettings) {
+        final Settings current = metadata.settings();
+        if (current.equals(updatedSettings)) {
+            return true;
+        }
+        final Set<String> changedSettingNames = new HashSet<>(current.keySet());
+        changedSettingNames.addAll(updatedSettings.keySet());
+        changedSettingNames.removeAll(ignoredSettings);
+        changedSettingNames.removeIf(setting -> Objects.equals(current.get(setting), updatedSettings.get(setting)));
+        changedSettingNames.removeAll(DYNAMIC_SETTING_NAMES);
+        return changedSettingNames.isEmpty();
+    }
+
     // Inspects all cluster state elements that contain a hint about what the current repository generation is and updates
     // #latestKnownRepoGen if a newer than currently known generation is found
     @Override
     public void updateState(ClusterState state) {
+        final Settings previousSettings = metadata.settings();
         metadata = getRepoMetadata(state);
+        final Settings updatedSettings = metadata.settings();
+        if (updatedSettings.equals(previousSettings) == false) {
+            snapshotRateLimiter = getRateLimiter(metadata.settings(), MAX_SNAPSHOT_BYTES_PER_SEC);
+            restoreRateLimiter = getRateLimiter(metadata.settings(), MAX_RESTORE_BYTES_PER_SEC);
+        }
+
         uncleanStart = uncleanStart && metadata.generation() != metadata.pendingGeneration();
         final boolean wasBestEffortConsistency = bestEffortConsistency;
         bestEffortConsistency = uncleanStart || isReadOnly() || metadata.generation() == RepositoryData.UNKNOWN_REPO_GEN;
@@ -1257,11 +1292,10 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
      *
      * @param repositorySettings repository settings
      * @param setting            setting to use to configure rate limiter
-     * @param defaultRate        default limiting rate
      * @return rate limiter or null of no throttling is needed
      */
-    private RateLimiter getRateLimiter(Settings repositorySettings, String setting, ByteSizeValue defaultRate) {
-        ByteSizeValue maxSnapshotBytesPerSec = repositorySettings.getAsBytesSize(setting, defaultRate);
+    private static RateLimiter getRateLimiter(Settings repositorySettings, Setting<ByteSizeValue> setting) {
+        ByteSizeValue maxSnapshotBytesPerSec = setting.get(repositorySettings);
         if (maxSnapshotBytesPerSec.getBytes() <= 0) {
             return null;
         } else {

test/framework/src/main/java/org/elasticsearch/snapshots/AbstractSnapshotIntegTestCase.java

@@ -190,6 +190,10 @@ public abstract class AbstractSnapshotIntegTestCase extends ESIntegTestCase {
         internalCluster().stopRandomNode(settings -> settings.get("node.name").equals(node));
     }
 
+    protected static String startDataNodeWithLargeSnapshotPool() {
+        return internalCluster().startDataOnlyNode(LARGE_SNAPSHOT_POOL_SETTINGS);
+    }
+
     public void waitForBlock(String node, String repository) throws Exception {
         logger.info("--> waiting for [{}] to be blocked on node [{}]", repository, node);
         MockRepository mockRepository = getRepositoryOnNode(repository, node);
@@ -277,10 +281,16 @@ public abstract class AbstractSnapshotIntegTestCase extends ESIntegTestCase {
         AbstractSnapshotIntegTestCase.<MockRepository>getRepositoryOnNode(repository, node).unblock();
     }
 
-    protected void createRepository(String repoName, String type, Settings.Builder settings) {
-        logger.info("--> creating repository [{}] [{}]", repoName, type);
+    protected void createRepository(String repoName, String type, Settings.Builder settings, boolean verify) {
+        logger.info("--> creating or updating repository [{}] [{}]", repoName, type);
         assertAcked(clusterAdmin().preparePutRepository(repoName)
-            .setType(type).setSettings(settings));
+                .setVerify(verify)
+                .setType(type)
+                .setSettings(settings));
+    }
+
+    protected void createRepository(String repoName, String type, Settings.Builder settings) {
+        createRepository(repoName, type, settings, true);
     }
 
     protected void createRepository(String repoName, String type, Path location) {
@@ -292,11 +302,7 @@ public abstract class AbstractSnapshotIntegTestCase extends ESIntegTestCase {
     }
 
     protected void createRepositoryNoVerify(String repoName, String type) {
-        logger.info("--> creating repository [{}] [{}]", repoName, type);
-        assertAcked(clusterAdmin().preparePutRepository(repoName)
-                .setVerify(false)
-                .setType(type)
-                .setSettings(randomRepositorySettings()));
+        createRepository(repoName, type, randomRepositorySettings(), false);
     }
 
     protected Settings.Builder randomRepositorySettings() {

test/framework/src/main/java/org/elasticsearch/snapshots/mockstore/MockRepository.java

@@ -29,6 +29,7 @@ import org.elasticsearch.common.settings.Setting;
 import org.elasticsearch.common.settings.Setting.Property;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.util.BigArrays;
+import org.elasticsearch.common.util.set.Sets;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.indices.recovery.RecoverySettings;
@@ -51,6 +52,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
+import java.util.Set;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -81,6 +83,11 @@ public class MockRepository extends FsRepository {
         }
     }
 
+    /**
+     * Setting name for a setting that can be updated dynamically to test {@link #canUpdateInPlace(Settings, Set)}.
+     */
+    public static final String DUMMY_UPDATABLE_SETTING_NAME = "dummy_setting";
+
     private final AtomicLong failureCounter = new AtomicLong();
 
     public long getFailureCount() {
@@ -162,6 +169,12 @@ public class MockRepository extends FsRepository {
         return overrideSettings(super.getMetadata(), env);
     }
 
+    @Override
+    public boolean canUpdateInPlace(Settings updatedSettings, Set<String> ignoredSettings) {
+        // allow updating dummy setting for test purposes
+        return super.canUpdateInPlace(updatedSettings, Sets.union(ignoredSettings, Set.of(DUMMY_UPDATABLE_SETTING_NAME)));
+    }
+
     private static RepositoryMetadata overrideSettings(RepositoryMetadata metadata, Environment environment) {
         // TODO: use another method of testing not being able to read the test file written by the master...
         // this is super duper hacky