HDDS-14356. Support OM Service Framework

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

@@ -248,6 +248,7 @@
 import org.apache.hadoop.ozone.om.execution.OMExecutionFlow;
 import org.apache.hadoop.ozone.om.ha.OMHAMetrics;
 import org.apache.hadoop.ozone.om.ha.OMHANodeDetails;
+import org.apache.hadoop.ozone.om.ha.OMServiceManager;
 import org.apache.hadoop.ozone.om.helpers.BasicOmKeyInfo;
 import org.apache.hadoop.ozone.om.helpers.BucketLayout;
 import org.apache.hadoop.ozone.om.helpers.DBUpdates;
@@ -515,6 +516,8 @@ public final class OzoneManager extends ServiceRuntimeInfoImpl
   private OmSnapshotManager omSnapshotManager;
   private volatile DirectoryDeletingService dirDeletingService;
 
+  private final OMServiceManager serviceManager;
+
   @SuppressWarnings("methodlength")
   private OzoneManager(OzoneConfiguration conf, StartupOption startupOption)
       throws IOException, AuthenticationException {
@@ -712,6 +715,9 @@ private OzoneManager(OzoneConfiguration conf, StartupOption startupOption)
     readBlacklist = OzoneBlacklist.getReadonlyBlacklist(conf);
 
     s3OzoneAdmins = OzoneAdmins.getS3Admins(conf);
+
+    serviceManager = new OMServiceManager();
+
     instantiateServices(false);
 
     // Create special volume s3v which is required for S3G.
@@ -2459,6 +2465,7 @@ public boolean stop() {
       if (omRatisSnapshotProvider != null) {
         omRatisSnapshotProvider.close();
       }
+      serviceManager.stop();
       DeletingServiceMetrics.unregister();
       OMPerformanceMetrics.unregister();
       RatisDropwizardExports.clear(ratisMetricsMap, ratisReporterList);
@@ -5626,6 +5633,10 @@ public ReconfigurationHandler getReconfigurationHandler() {
     return reconfigurationHandler;
   }
 
+  public OMServiceManager getOMServiceManager() {
+    return serviceManager;
+  }
+
   /**
    * Wait until both buffers are flushed.  This is used in cases like
    * "follower bootstrap tarball creation" where the rocksDb for the active

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

@@ -0,0 +1,61 @@
+/*
+ * 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
+ *
+ *      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.apache.hadoop.ozone.om.ha;
+
+/**
+ * Interface for stateful background service in OM.
+ *
+ * Provide a fine-grained method to manipulate the status of these background
+ * services.
+ */
+public interface OMService {
+  /**
+   * Notify raft or safe mode related status changed.
+   */
+  void notifyStatusChanged();
+
+  /**
+   * @return true, if next iteration of Service should take effect,
+   *         false, if next iteration of Service should be skipped.
+   */
+  boolean shouldRun();
+
+  /**
+   * @return name of the Service.
+   */
+  String getServiceName();
+
+  /**
+   * Status of Service.
+   */
+  enum ServiceStatus {
+    RUNNING,
+    PAUSING
+  }
+
+  /**
+   * starts the OM service.
+   */
+  void start() throws OMServiceException;
+
+  /**
+   * stops the OM service.
+   */
+  void stop();
+
+}

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

@@ -0,0 +1,40 @@
+/*
+ * 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
+ *
+ *      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.apache.hadoop.ozone.om.ha;
+
+/**
+ * Checked exceptions thrown by an {@link OMService}.
+ */
+public class OMServiceException extends Exception {
+
+  public OMServiceException() {
+    super();
+  }
+
+  public OMServiceException(String s) {
+    super(s);
+  }
+
+  public OMServiceException(String message, Throwable cause) {
+    super(message, cause);
+  }
+
+  public OMServiceException(Throwable cause) {
+    super(cause);
+  }
+}

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

@@ -0,0 +1,77 @@
+/*
+ * 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
+ *
+ *      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.apache.hadoop.ozone.om.ha;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Manipulate background services in OM.
+ */
+public final class OMServiceManager {
+  private static final Logger LOG =
+      LoggerFactory.getLogger(OMServiceManager.class);
+
+  private final List<OMService> services = new ArrayList<>();
+
+  /**
+   * Register an OMService to OMServiceManager.
+   */
+  public synchronized void register(OMService service) {
+    Objects.requireNonNull(service);
+    LOG.info("Registering service {}.", service.getServiceName());
+    services.add(service);
+  }
+
+  /**
+   * Notify raft related status changed.
+   */
+  public synchronized void notifyStatusChanged() {
+    for (OMService service : services) {
+      LOG.debug("Notify service:{}.", service.getServiceName());
+      service.notifyStatusChanged();
+    }
+  }
+
+  /**
+   * Start all running services.
+   */
+  public synchronized void start() {
+    for (OMService service : services) {
+      LOG.debug("Starting service:{}.", service.getServiceName());
+      try {
+        service.start();
+      } catch (OMServiceException e) {
+        LOG.warn("Could not start " + service.getServiceName(), e);
+      }
+    }
+  }
+
+  /**
+   * Stops all running services.
+   */
+  public synchronized void stop() {
+    for (OMService service : services) {
+      LOG.debug("Stopping service:{}.", service.getServiceName());
+      service.stop();
+    }
+  }
+}

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

@@ -193,6 +193,7 @@ public void notifyLeaderReady() {
     if (metrics != null) {
       metrics.addRatisEvent("Ready to serve requests as the leader");
     }
+    ozoneManager.getOMServiceManager().notifyStatusChanged();
   }
 
   @Override
@@ -202,6 +203,7 @@ public void notifyNotLeader(Collection<TransactionContext> pendingEntries) {
     if (metrics != null) {
       metrics.addRatisEvent("current leader OM steps down.");
     }
+    ozoneManager.getOMServiceManager().notifyStatusChanged();
   }
 
   @Override
@@ -219,6 +221,8 @@ public void notifyLeaderChanged(RaftGroupMemberId groupMemberId,
     previousLeaderId = newLeaderId;
     // Initialize OMHAMetrics
     ozoneManager.omHAMetricsInit(newLeaderId.toString());
+    // Notify OM service of leader change
+    ozoneManager.getOMServiceManager().notifyStatusChanged();
 
     Map<String, String> auditParams = new LinkedHashMap<>();
     auditParams.put(AUDIT_PARAM_PREVIOUS_LEADER,

hadoop-ozone/ozone-manager/src/test/java/org/apache/hadoop/ozone/om/ha/TestOMServiceManager.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
+ *
+ *      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.apache.hadoop.ozone.om.ha;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import org.junit.jupiter.api.Test;
+
+/**
+ * Tests for {@link OMServiceManager}.
+ */
+public class TestOMServiceManager {
+
+  private static class OMContext {
+    private boolean isLeader;
+
+    OMContext() {
+      isLeader = false;
+    }
+
+    public boolean isLeader() {
+      return isLeader;
+    }
+
+    public void setLeader(boolean leader) {
+      this.isLeader = leader;
+    }
+  }
+
+  @Test
+  public void testServiceRunWhenLeader() {
+
+    OMContext omContext = new OMContext();
+
+    // A service runs when it is a leader.
+    OMService serviceRunWhenLeader = new OMService() {
+      private ServiceStatus serviceStatus = ServiceStatus.PAUSING;
+
+      @Override
+      public void notifyStatusChanged() {
+        if (omContext.isLeader()) {
+          serviceStatus = ServiceStatus.RUNNING;
+        } else {
+          serviceStatus = ServiceStatus.PAUSING;
+        }
+      }
+
+      @Override
+      public boolean shouldRun() {
+        return serviceStatus == ServiceStatus.RUNNING;
+      }
+
+      @Override
+      public String getServiceName() {
+        return "serviceRunWhenLeader";
+      }
+
+      @Override
+      public void start() throws OMServiceException {
+
+      }
+
+      @Override
+      public void stop() {
+
+      }
+    };
+
+    OMServiceManager serviceManager = new OMServiceManager();
+    serviceManager.register(serviceRunWhenLeader);
+
+    // PAUSING at the beginning.
+    assertFalse(serviceRunWhenLeader.shouldRun());
+
+    // RUNNING when becoming leader.
+    omContext.setLeader(true);
+    serviceManager.notifyStatusChanged();
+    assertTrue(serviceRunWhenLeader.shouldRun());
+
+    // PAUSING when stepping down.
+    omContext.setLeader(false);
+    serviceManager.notifyStatusChanged();
+    assertFalse(serviceRunWhenLeader.shouldRun());
+
+  }
+
+}

hadoop-ozone/ozone-manager/src/test/java/org/apache/hadoop/ozone/om/ratis/TestOzoneManagerStateMachine.java

@@ -61,6 +61,7 @@
 import org.apache.hadoop.ozone.om.OzoneManager;
 import org.apache.hadoop.ozone.om.OzoneManagerPrepareState;
 import org.apache.hadoop.ozone.om.exceptions.OMException;
+import org.apache.hadoop.ozone.om.ha.OMServiceManager;
 import org.apache.hadoop.ozone.om.helpers.OMRatisHelper;
 import org.apache.hadoop.ozone.om.lock.OMLockDetails;
 import org.apache.hadoop.ozone.om.ratis_snapshot.OmRatisSnapshotProvider;
@@ -111,6 +112,7 @@ public class TestOzoneManagerStateMachine {
   private RequestHandler handler;
   private ExecutorService executor;
   private OzoneManagerStateMachine sm;
+  private OMServiceManager serviceManager;
 
   @BeforeEach
   public void setup() {
@@ -119,6 +121,8 @@ public void setup() {
     doubleBuffer = mock(OzoneManagerDoubleBuffer.class);
     handler = mock(RequestHandler.class);
     executor = Executors.newSingleThreadExecutor();
+    serviceManager = mock(OMServiceManager.class);
+    when(om.getOMServiceManager()).thenReturn(serviceManager);
     sm = new OzoneManagerStateMachine(om, doubleBuffer, handler, executor, null);
   }
 
@@ -878,6 +882,7 @@ public void testNotifyLeaderReady() {
     sm.notifyLeaderReady();
 
     verify(snapshotManager).resetInFlightSnapshotCount();
+    verify(serviceManager).notifyStatusChanged();
   }
 
   // --- getLatestSnapshot tests ---