HDDS-8166. [Snapshot] Add a config to enable or disable Ozone snapshot feature on OM

hadoop-hdds/common/src/main/resources/ozone-default.xml

@@ -3200,6 +3200,16 @@
     </description>
   </property>
 
+  <property>
+    <name>ozone.filesystem.snapshot.enabled</name>
+    <value>true</value>
+    <tag>OZONE, OM</tag>
+    <description>
+      Enables Ozone filesystem snapshot feature if set to true on the OM side.
+      Disables it otherwise.
+    </description>
+  </property>
+
   <property>
     <name>ozone.snapshot.deleting.service.timeout</name>
     <value>300s</value>

hadoop-ozone/common/src/main/java/org/apache/hadoop/ozone/om/OMConfigKeys.java

@@ -45,6 +45,10 @@ public final class OMConfigKeys {
   private OMConfigKeys() {
   }
 
+  public static final String OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY =
+      "ozone.filesystem.snapshot.enabled";
+  public static final boolean OZONE_FILESYSTEM_SNAPSHOT_ENABLED_DEFAULT = true;
+
   // Location where the OM stores its DB files. In the future we may support
   // multiple entries for performance (sharding)..
   public static final String OZONE_OM_DB_DIRS = "ozone.om.db.dirs";

hadoop-ozone/dist/src/main/compose/ozone-om-ha/docker-config

@@ -93,3 +93,6 @@ OZONE_CONF_DIR=/etc/hadoop
 OZONE_LOG_DIR=/var/log/hadoop
 
 no_proxy=om,scm,s3g,recon,kdc,localhost,127.0.0.1
+
+# Explicitly enable filesystem snapshot feature for this Docker compose cluster
+OZONE-SITE.XML_ozone.filesystem.snapshot.enabled=true

hadoop-ozone/dist/src/main/compose/ozone/docker-config

@@ -53,3 +53,6 @@ OZONE_CONF_DIR=/etc/hadoop
 OZONE_LOG_DIR=/var/log/hadoop
 
 no_proxy=om,scm,s3g,recon,kdc,localhost,127.0.0.1
+
+# Explicitly enable filesystem snapshot feature for this Docker compose cluster
+OZONE-SITE.XML_ozone.filesystem.snapshot.enabled=true

hadoop-ozone/dist/src/main/compose/ozonesecure-ha/docker-config

@@ -159,3 +159,6 @@ OZONE_CONF_DIR=/etc/hadoop
 OZONE_LOG_DIR=/var/log/hadoop
 
 no_proxy=om,scm,recon,s3g,kdc,localhost,127.0.0.1
+
+# Explicitly enable filesystem snapshot feature for this Docker compose cluster
+OZONE-SITE.XML_ozone.filesystem.snapshot.enabled=true

hadoop-ozone/dist/src/main/compose/ozonesecure-mr/docker-config

@@ -149,3 +149,6 @@ OZONE_CONF_DIR=/etc/hadoop
 OZONE_LOG_DIR=/var/log/hadoop
 
 no_proxy=om,scm,s3g,recon,kdc,localhost,127.0.0.1
+
+# Explicitly enable filesystem snapshot feature for this Docker compose cluster
+OZONE-SITE.XML_ozone.filesystem.snapshot.enabled=true

hadoop-ozone/dist/src/main/compose/ozonesecure/docker-config

@@ -182,3 +182,6 @@ OZONE-SITE.XML_ozone.om.multitenancy.ranger.sync.timeout=10s
 # change or let all OMs write to AccessController if this dev flag is set.
 #
 OZONE-SITE.XML_ozone.om.tenant.dev.skip.ranger=true
+
+# Explicitly enable filesystem snapshot feature for this Docker compose cluster
+OZONE-SITE.XML_ozone.filesystem.snapshot.enabled=true

hadoop-ozone/dist/src/main/compose/upgrade/compose/ha/docker-config

@@ -61,3 +61,7 @@ OZONE-SITE.XML_ozone.recon.address=recon:9891
 no_proxy=om1,om2,om3,scm1,scm2,scm3,s3g,kdc,localhost,127.0.0.1
 
 OM_SERVICE_ID=omservice
+
+# Explicitly enable filesystem snapshot feature for this Docker compose cluster
+# Does not take effect on Ozone versions < 1.4.0
+OZONE-SITE.XML_ozone.filesystem.snapshot.enabled=true

hadoop-ozone/dist/src/main/compose/upgrade/compose/non-ha/docker-config

@@ -40,3 +40,7 @@ OZONE_CONF_DIR=/etc/hadoop
 OZONE_LOG_DIR=/var/log/hadoop
 
 no_proxy=om,scm,s3g,kdc,localhost,127.0.0.1
+
+# Explicitly enable filesystem snapshot feature for this Docker compose cluster
+# Does not take effect on Ozone versions < 1.4.0
+OZONE-SITE.XML_ozone.filesystem.snapshot.enabled=true

hadoop-ozone/dist/src/main/compose/upgrade/compose/om-ha/docker-config

@@ -56,3 +56,7 @@ OZONE-SITE.XML_ozone.recon.address=recon:9891
 no_proxy=om1,om2,om3,scm,s3g,kdc,localhost,127.0.0.1
 
 OM_SERVICE_ID=omservice
+
+# Explicitly enable filesystem snapshot feature for this Docker compose cluster
+# Does not take effect on Ozone versions < 1.4.0
+OZONE-SITE.XML_ozone.filesystem.snapshot.enabled=true

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/fs/ozone/TestOzoneFsSnapshot.java

@@ -29,6 +29,7 @@
 import org.apache.commons.lang3.RandomStringUtils;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
 import org.apache.hadoop.ozone.MiniOzoneCluster;
+import org.apache.hadoop.ozone.om.OMConfigKeys;
 import org.apache.hadoop.ozone.om.OzoneManager;
 import org.apache.hadoop.ozone.om.helpers.SnapshotInfo;
 import org.apache.hadoop.util.ToolRunner;
@@ -76,6 +77,8 @@ public class TestOzoneFsSnapshot {
   @BeforeAll
   public static void initClass() throws Exception {
     OzoneConfiguration conf = new OzoneConfiguration();
+    // Enable filesystem snapshot feature for the test regardless of the default
+    conf.setBoolean(OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY, true);
 
     // Start the cluster
     cluster = MiniOzoneCluster.newOMHABuilder(conf)

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/freon/TestOMSnapshotDAG.java

@@ -28,6 +28,7 @@
 import org.apache.hadoop.ozone.client.OzoneBucket;
 import org.apache.hadoop.ozone.client.OzoneClient;
 import org.apache.hadoop.ozone.client.OzoneVolume;
+import org.apache.hadoop.ozone.om.OMConfigKeys;
 import org.apache.hadoop.ozone.om.OMMetadataManager;
 import org.apache.hadoop.ozone.om.OmMetadataManagerImpl;
 import org.apache.hadoop.ozone.om.OmSnapshotManager;
@@ -98,6 +99,8 @@ public static void init() throws Exception {
     raftClientConfig.setRpcRequestTimeout(Duration.ofSeconds(3));
     raftClientConfig.setRpcWatchRequestTimeout(Duration.ofSeconds(3));
     conf.setFromObject(raftClientConfig);
+    // Enable filesystem snapshot feature for the test regardless of the default
+    conf.setBoolean(OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY, true);
 
     // Set DB CF write buffer to a much lower value so that flush and compaction
     // happens much more frequently without having to create a lot of keys.

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/TestOmSnapshot.java

@@ -163,6 +163,8 @@ private void init() throws Exception {
     conf.setBoolean(OMConfigKeys.OZONE_OM_SNAPSHOT_FORCE_FULL_DIFF,
         forceFullSnapshotDiff);
     conf.setEnum(HDDS_DB_PROFILE, DBProfile.TEST);
+    // Enable filesystem snapshot feature for the test regardless of the default
+    conf.setBoolean(OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY, true);
 
     cluster = MiniOzoneCluster.newOMHABuilder(conf)
         .setClusterId(clusterId)

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/TestOmSnapshotDisabled.java

@@ -0,0 +1,103 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership.  The ASF
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.apache.hadoop.ozone.om;
+
+import org.apache.commons.lang3.RandomStringUtils;
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.hdds.utils.IOUtils;
+import org.apache.hadoop.hdds.utils.db.DBProfile;
+import org.apache.hadoop.ozone.MiniOzoneCluster;
+import org.apache.hadoop.ozone.MiniOzoneHAClusterImpl;
+import org.apache.hadoop.ozone.client.ObjectStore;
+import org.apache.hadoop.ozone.client.OzoneClient;
+import org.apache.hadoop.ozone.client.OzoneVolume;
+import org.apache.hadoop.ozone.om.exceptions.OMException;
+import org.apache.hadoop.ozone.om.helpers.BucketLayout;
+import org.apache.ozone.test.LambdaTestUtils;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.Timeout;
+
+import java.util.UUID;
+
+import static org.apache.hadoop.hdds.HddsConfigKeys.HDDS_DB_PROFILE;
+
+/**
+ * Integration test to verify Ozone snapshot RPCs throw exception when called.
+ */
+public class TestOmSnapshotDisabled {
+
+  private static MiniOzoneCluster cluster = null;
+  private static OzoneClient client;
+  private static ObjectStore store;
+
+  @BeforeAll
+  @Timeout(60)
+  public static void init() throws Exception {
+    OzoneConfiguration conf = new OzoneConfiguration();
+    String clusterId = UUID.randomUUID().toString();
+    String scmId = UUID.randomUUID().toString();
+    conf.set(OMConfigKeys.OZONE_DEFAULT_BUCKET_LAYOUT,
+        BucketLayout.LEGACY.name());
+    conf.setEnum(HDDS_DB_PROFILE, DBProfile.TEST);
+    // Disable filesystem snapshot feature for this test
+    conf.setBoolean(OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY, false);
+
+    cluster = MiniOzoneCluster.newOMHABuilder(conf)
+        .setClusterId(clusterId)
+        .setScmId(scmId)
+        .setOMServiceId("om-service-test1")
+        .setNumOfOzoneManagers(3)
+        .build();
+    cluster.waitForClusterToBeReady();
+    client = cluster.newClient();
+
+    OzoneManager leaderOzoneManager =
+        ((MiniOzoneHAClusterImpl) cluster).getOMLeader();
+    OzoneConfiguration leaderConfig = leaderOzoneManager.getConfiguration();
+    cluster.setConf(leaderConfig);
+    store = client.getObjectStore();
+  }
+
+  @AfterAll
+  public static void tearDown() throws Exception {
+    IOUtils.closeQuietly(client);
+    if (cluster != null) {
+      cluster.shutdown();
+    }
+  }
+
+  @Test
+  public void testExceptionThrown() throws Exception {
+    String volumeName = "vol-" + RandomStringUtils.randomNumeric(5);
+    String bucketName = "buck-" + RandomStringUtils.randomNumeric(5);
+    String snapshotName = "snap-" + RandomStringUtils.randomNumeric(5);
+
+    store.createVolume(volumeName);
+    OzoneVolume volume = store.getVolume(volumeName);
+    volume.createBucket(bucketName);
+
+    // create snapshot should throw
+    LambdaTestUtils.intercept(OMException.class, "FEATURE_NOT_ENABLED",
+        () -> store.createSnapshot(volumeName, bucketName, snapshotName));
+    // delete snapshot should throw
+    LambdaTestUtils.intercept(OMException.class, "FEATURE_NOT_ENABLED",
+        () -> store.deleteSnapshot(volumeName, bucketName, snapshotName));
+  }
+}

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/TestOmSnapshotFileSystem.java

@@ -108,8 +108,6 @@ public class TestOmSnapshotFileSystem {
   private static final Logger LOG =
       LoggerFactory.getLogger(TestOmSnapshot.class);
 
-
-
   @Rule
   public Timeout timeout = new Timeout(120, TimeUnit.SECONDS);
 

hadoop-ozone/integration-test/src/test/java/org/apache/hadoop/ozone/om/snapshot/TestOzoneSnapshotRestore.java

@@ -34,6 +34,7 @@
 import org.apache.hadoop.ozone.client.io.OzoneOutputStream;
 import org.apache.hadoop.ozone.client.BucketArgs;
 import org.apache.hadoop.ozone.om.KeyManagerImpl;
+import org.apache.hadoop.ozone.om.OMConfigKeys;
 import org.apache.hadoop.ozone.om.OMStorage;
 import org.apache.hadoop.ozone.om.OmSnapshotManager;
 import org.apache.hadoop.ozone.om.OzoneManager;
@@ -91,6 +92,9 @@ private static Stream<Arguments> bucketTypesCombinations() {
   @BeforeEach
   public void init() throws Exception {
     OzoneConfiguration conf = new OzoneConfiguration();
+    // Enable filesystem snapshot feature for the test regardless of the default
+    conf.setBoolean(OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY, true);
+
     String clusterId = UUID.randomUUID().toString();
     String scmId = UUID.randomUUID().toString();
     String serviceID = OM_SERVICE_ID + RandomStringUtils.randomNumeric(5);

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/KeyManagerImpl.java

@@ -255,7 +255,9 @@ public void start(OzoneConfiguration configuration) {
       openKeyCleanupService.start();
     }
 
-    if (snapshotSstFilteringService == null) {
+    if (snapshotSstFilteringService == null &&
+        ozoneManager.isFilesystemSnapshotEnabled()) {
+
       long serviceInterval = configuration.getTimeDuration(
           OZONE_SNAPSHOT_SST_FILTERING_SERVICE_INTERVAL,
           OZONE_SNAPSHOT_SST_FILTERING_SERVICE_INTERVAL_DEFAULT,
@@ -272,7 +274,9 @@ public void start(OzoneConfiguration configuration) {
       }
     }
 
-    if (snapshotDeletingService == null) {
+    if (snapshotDeletingService == null &&
+        ozoneManager.isFilesystemSnapshotEnabled()) {
+
       long snapshotServiceInterval = configuration.getTimeDuration(
           OZONE_SNAPSHOT_DELETING_SERVICE_INTERVAL,
           OZONE_SNAPSHOT_DELETING_SERVICE_INTERVAL_DEFAULT,

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmMetadataManagerImpl.java

@@ -1550,7 +1550,7 @@ public List<BlockGroup> getPendingDeletionKeys(final int keyCount,
    * Get the latest OmSnapshot for a snapshot path.
    */
   public OmSnapshot getLatestSnapshot(String volumeName, String bucketName,
-                                       OmSnapshotManager snapshotManager)
+                                      OmSnapshotManager snapshotManager)
       throws IOException {
 
     String latestPathSnapshot =

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OmSnapshotManager.java

@@ -158,7 +158,18 @@ public final class OmSnapshotManager implements AutoCloseable {
   // Soft limit of the snapshot cache size.
   private final int softCacheSize;
 
+  /**
+   * TODO: [SNAPSHOT] HDDS-8529: Refactor the constructor in a way that when
+   *  ozoneManager.isFilesystemSnapshotEnabled() returns false,
+   *  no snapshot-related background job or initialization would run,
+   *  except for applying previously committed Ratis transactions in e.g.:
+   *  1. {@link OMKeyPurgeRequest#validateAndUpdateCache}
+   *  2. {@link OMDirectoriesPurgeRequestWithFSO#validateAndUpdateCache}
+   */
   public OmSnapshotManager(OzoneManager ozoneManager) {
+    LOG.info("Ozone filesystem snapshot feature is {}.",
+        ozoneManager.isFilesystemSnapshotEnabled() ? "enabled" : "disabled");
+
     this.options = new ManagedDBOptions();
     this.options.setCreateIfMissing(true);
     this.columnFamilyOptions = new ManagedColumnFamilyOptions();
@@ -259,17 +270,21 @@ public OmSnapshotManager(OzoneManager ozoneManager) {
             OZONE_OM_SNAPSHOT_DIFF_CLEANUP_SERVICE_TIMEOUT_DEFAULT,
             TimeUnit.MILLISECONDS);
 
-    this.snapshotDiffCleanupService = new SnapshotDiffCleanupService(
-        diffCleanupServiceInterval,
-        diffCleanupServiceTimeout,
-        ozoneManager,
-        snapshotDiffDb,
-        snapDiffJobCf,
-        snapDiffPurgedJobCf,
-        snapDiffReportCf,
-        codecRegistry
-    );
-    this.snapshotDiffCleanupService.start();
+    if (ozoneManager.isFilesystemSnapshotEnabled()) {
+      this.snapshotDiffCleanupService = new SnapshotDiffCleanupService(
+          diffCleanupServiceInterval,
+          diffCleanupServiceTimeout,
+          ozoneManager,
+          snapshotDiffDb,
+          snapDiffJobCf,
+          snapDiffPurgedJobCf,
+          snapDiffReportCf,
+          codecRegistry
+      );
+      this.snapshotDiffCleanupService.start();
+    } else {
+      this.snapshotDiffCleanupService = null;
+    }
   }
 
   private CacheLoader<String, OmSnapshot> createCacheLoader() {
@@ -479,7 +494,7 @@ private static void deleteKeysInSnapshotScopeFromDTableInternal(
   public IOmMetadataReader checkForSnapshot(String volumeName,
                                             String bucketName, String keyname)
       throws IOException {
-    if (keyname == null) {
+    if (keyname == null || !ozoneManager.isFilesystemSnapshotEnabled()) {
       return ozoneManager.getOmMetadataReader();
     }
 

hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/OzoneManager.java

@@ -434,6 +434,8 @@ public final class OzoneManager extends ServiceRuntimeInfoImpl
   private final OzoneLockProvider ozoneLockProvider;
   private OMPerformanceMetrics perfMetrics;
 
+  private boolean fsSnapshotEnabled;
+
   /**
    * OM Startup mode.
    */
@@ -544,6 +546,10 @@ private OzoneManager(OzoneConfiguration conf, StartupOption startupOption)
         OMConfigKeys.OZONE_OM_RATIS_ENABLE_KEY,
         OMConfigKeys.OZONE_OM_RATIS_ENABLE_DEFAULT);
 
+    fsSnapshotEnabled = configuration.getBoolean(
+        OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_KEY,
+        OMConfigKeys.OZONE_FILESYSTEM_SNAPSHOT_ENABLED_DEFAULT);
+
     String defaultBucketLayoutString =
         configuration.getTrimmed(OZONE_DEFAULT_BUCKET_LAYOUT,
             OZONE_DEFAULT_BUCKET_LAYOUT_DEFAULT);
@@ -783,6 +789,8 @@ private void instantiateServices(boolean withNewSnapshot) throws IOException {
         perfMetrics);
     omMetadataReader = new OmMetadataReader(keyManager, prefixManager,
         this, LOG, AUDIT, metrics);
+
+    // TODO: [SNAPSHOT] Revisit this in HDDS-8529.
     omSnapshotManager = new OmSnapshotManager(this);
 
     // Snapshot metrics
@@ -3994,6 +4002,13 @@ public boolean isRatisEnabled() {
     return isRatisEnabled;
   }
 
+  /**
+   * @return true if Ozone filesystem snapshot is enabled, false otherwise.
+   */
+  public boolean isFilesystemSnapshotEnabled() {
+    return fsSnapshotEnabled;
+  }
+
   /**
    * Get DB updates since a specific sequence number.
    *