[improve][broker] Gracefully shut down load balancer extension

Author: heesung-sn

pulsar-broker/src/main/java/org/apache/pulsar/broker/PulsarService.java

@@ -382,6 +382,17 @@ public void closeMetadataServiceSession() throws Exception {
         localMetadataStore.close();
     }
 
+    private void closeLeaderElectionService() throws Exception {
+        if (ExtensibleLoadManagerImpl.isLoadManagerExtensionEnabled(config)) {
+            ExtensibleLoadManagerImpl.get(loadManager.get()).getLeaderElectionService().close();
+        } else {
+            if (this.leaderElectionService != null) {
+                this.leaderElectionService.close();
+                this.leaderElectionService = null;
+            }
+        }
+    }
+
     @Override
     public void close() throws PulsarServerException {
         try {
@@ -502,10 +513,7 @@ public CompletableFuture<Void> closeAsync() {
                 this.bkClientFactory = null;
             }
 
-            if (this.leaderElectionService != null) {
-                this.leaderElectionService.close();
-                this.leaderElectionService = null;
-            }
+            closeLeaderElectionService();
 
             if (adminClient != null) {
                 adminClient.close();
@@ -1316,7 +1324,11 @@ public boolean isRunning() {
      * @return a reference of the current <code>LeaderElectionService</code> instance.
      */
     public LeaderElectionService getLeaderElectionService() {
-        return this.leaderElectionService;
+        if (ExtensibleLoadManagerImpl.isLoadManagerExtensionEnabled(config)) {
+            return ExtensibleLoadManagerImpl.get(loadManager.get()).getLeaderElectionService();
+        } else {
+            return this.leaderElectionService;
+        }
     }
 
     /**

pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/ExtensibleLoadManagerImpl.java

@@ -380,12 +380,22 @@ public CompletableFuture<Optional<BrokerLookupData>> assign(Optional<ServiceUnit
     }
 
     public CompletableFuture<Optional<String>> selectAsync(ServiceUnitId bundle) {
+        return selectAsync(bundle, Optional.empty());
+    }
+
+    public CompletableFuture<Optional<String>> selectAsync(ServiceUnitId bundle,
+                                                           Optional<Set<String>> excludeBrokerSet) {
         BrokerRegistry brokerRegistry = getBrokerRegistry();
         return brokerRegistry.getAvailableBrokerLookupDataAsync()
                 .thenCompose(availableBrokers -> {
                     LoadManagerContext context = this.getContext();
 
                     Map<String, BrokerLookupData> availableBrokerCandidates = new HashMap<>(availableBrokers);
+                    if (excludeBrokerSet.isPresent()) {
+                        for (String exclude : excludeBrokerSet.get()) {
+                            availableBrokerCandidates.remove(exclude);
+                        }
+                    }
 
                     // Filter out brokers that do not meet the rules.
                     List<BrokerFilter> filterPipeline = getBrokerFilterPipeline();
@@ -685,4 +695,10 @@ private void monitor() {
             log.error("Failed to get the channel ownership.", e);
         }
     }
+
+    public void disableBroker() throws Exception {
+        serviceUnitStateChannel.cleanOwnerships();
+        leaderElectionService.close();
+        brokerRegistry.unregister();
+    }
 }

pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/ExtensibleLoadManagerWrapper.java

@@ -74,7 +74,7 @@ public CompletableFuture<Boolean> checkOwnershipAsync(Optional<ServiceUnitId> to
 
     @Override
     public void disableBroker() throws Exception {
-        this.loadManager.getBrokerRegistry().unregister();
+        this.loadManager.disableBroker();
     }
 
     @Override

pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/channel/ServiceUnitStateChannel.java

@@ -206,4 +206,9 @@ public interface ServiceUnitStateChannel extends Closeable {
      * Cancels the ownership monitor.
      */
     void cancelOwnershipMonitor();
+
+    /**
+     * Cleans the service unit ownerships from the current broker's channel.
+     */
+    void cleanOwnerships();
 }

pulsar-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/channel/ServiceUnitStateChannelImpl.java

@@ -110,6 +110,10 @@ public class ServiceUnitStateChannelImpl implements ServiceUnitStateChannel {
 
     public static final CompressionType MSG_COMPRESSION_TYPE = CompressionType.ZSTD;
     private static final long MAX_IN_FLIGHT_STATE_WAITING_TIME_IN_MILLIS = 30 * 1000; // 30sec
+
+    private static final int OWNERSHIP_CLEAN_UP_MAX_WAIT_TIME_IN_MILLIS = 5000;
+    private static final int OWNERSHIP_CLEAN_UP_WAIT_RETRY_DELAY_IN_MILLIS = 100;
+    private static final int OWNERSHIP_CLEAN_UP_CONVERGENCE_DELAY_IN_MILLIS = 3000;
     public static final long VERSION_ID_INIT = 1; // initial versionId
     private static final long OWNERSHIP_MONITOR_DELAY_TIME_IN_SECS = 60;
     public static final long MAX_CLEAN_UP_DELAY_TIME_IN_SECS = 3 * 60; // 3 mins
@@ -694,6 +698,8 @@ private void handleOwnEvent(String serviceUnit, ServiceUnitStateData data) {
         if (isTargetBroker(data.dstBroker())) {
             log(null, serviceUnit, data, null);
             lastOwnEventHandledAt = System.currentTimeMillis();
+        } else if (data.force() && isTargetBroker(data.sourceBroker())) {
+            closeServiceUnit(serviceUnit);
         }
     }
 
@@ -1114,13 +1120,13 @@ private ServiceUnitStateData getOverrideInactiveBrokerStateData(ServiceUnitState
                     Map.copyOf(orphanData.splitServiceUnitToDestBroker()),
                     true, getNextVersionId(orphanData));
         } else {
-            return new ServiceUnitStateData(Owned, selectedBroker, true, getNextVersionId(orphanData));
+            return new ServiceUnitStateData(Owned, selectedBroker, orphanData.dstBroker(),
+                    true, getNextVersionId(orphanData));
         }
     }
 
-    private void overrideOwnership(String serviceUnit, ServiceUnitStateData orphanData) {
-
-        Optional<String> selectedBroker = selectBroker(serviceUnit);
+    private void overrideOwnership(String serviceUnit, ServiceUnitStateData orphanData, String inactiveBroker) {
+        Optional<String> selectedBroker = selectBroker(serviceUnit, inactiveBroker);
         if (selectedBroker.isPresent()) {
             var override = getOverrideInactiveBrokerStateData(orphanData, selectedBroker.get());
             log.info("Overriding ownership serviceUnit:{} from orphanData:{} to overrideData:{}",
@@ -1140,8 +1146,37 @@ private void overrideOwnership(String serviceUnit, ServiceUnitStateData orphanDa
         }
     }
 
+    public void cleanOwnerships() {
+        doCleanup(lookupServiceAddress);
+        long started = System.currentTimeMillis();
+        while (System.currentTimeMillis() - started < OWNERSHIP_CLEAN_UP_MAX_WAIT_TIME_IN_MILLIS) {
+            boolean cleaned = true;
+            for (var data : tableview.values()) {
+                if (data.state() == Owned && data.dstBroker().equals(lookupServiceAddress)) {
+                    cleaned = false;
+                    break;
+                }
+            }
+            if (cleaned) {
+                try {
+                    MILLISECONDS.sleep(OWNERSHIP_CLEAN_UP_CONVERGENCE_DELAY_IN_MILLIS);
+                } catch (InterruptedException e) {
+                    log.warn("Interrupted while gracefully waiting for the cleanup convergence.");
+                }
+                break;
+            } else {
+                try {
+                    MILLISECONDS.sleep(OWNERSHIP_CLEAN_UP_WAIT_RETRY_DELAY_IN_MILLIS);
+                } catch (InterruptedException e) {
+                    log.warn("Interrupted while delaying the next service unit clean-up. Cleaning broker:{}",
+                            lookupServiceAddress);
+                }
+            }
+        }
+    }
+
 
-    private void doCleanup(String broker)  {
+    private synchronized void doCleanup(String broker)  {
         long startTime = System.nanoTime();
         log.info("Started ownership cleanup for the inactive broker:{}", broker);
         int orphanServiceUnitCleanupCnt = 0;
@@ -1153,13 +1188,13 @@ private void doCleanup(String broker)  {
             var state = state(stateData);
             if (StringUtils.equals(broker, stateData.dstBroker())) {
                 if (isActiveState(state)) {
-                    overrideOwnership(serviceUnit, stateData);
+                    overrideOwnership(serviceUnit, stateData, broker);
                     orphanServiceUnitCleanupCnt++;
                 }
 
             } else if (StringUtils.equals(broker, stateData.sourceBroker())) {
                 if (isInFlightState(state)) {
-                    overrideOwnership(serviceUnit, stateData);
+                    overrideOwnership(serviceUnit, stateData, broker);
                     orphanServiceUnitCleanupCnt++;
                 }
             }
@@ -1194,18 +1229,20 @@ private void doCleanup(String broker)  {
 
     }
 
-    private Optional<String> selectBroker(String serviceUnit) {
+    private Optional<String> selectBroker(String serviceUnit, String inactiveBroker) {
         try {
-            return loadManager.selectAsync(getNamespaceBundle(serviceUnit))
+            return loadManager.selectAsync(getNamespaceBundle(serviceUnit), Optional.of(Set.of(inactiveBroker)))
                     .get(inFlightStateWaitingTimeInMillis, MILLISECONDS);
         } catch (Throwable e) {
             log.error("Failed to select a broker for serviceUnit:{}", serviceUnit);
         }
         return Optional.empty();
     }
 
-    private Optional<ServiceUnitStateData> getRollForwardStateData(String serviceUnit, long nextVersionId) {
-        Optional<String> selectedBroker = selectBroker(serviceUnit);
+    private Optional<ServiceUnitStateData> getRollForwardStateData(String serviceUnit,
+                                                                   String inactiveBroker,
+                                                                   long nextVersionId) {
+        Optional<String> selectedBroker = selectBroker(serviceUnit, inactiveBroker);
         if (selectedBroker.isEmpty()) {
             return Optional.empty();
         }
@@ -1220,7 +1257,7 @@ private Optional<ServiceUnitStateData> getOverrideInFlightStateData(
         var state = orphanData.state();
         switch (state) {
             case Assigning: {
-                return getRollForwardStateData(serviceUnit, nextVersionId);
+                return getRollForwardStateData(serviceUnit, orphanData.dstBroker(), nextVersionId);
             }
             case Splitting: {
                 return Optional.of(new ServiceUnitStateData(Splitting,
@@ -1233,7 +1270,7 @@ private Optional<ServiceUnitStateData> getOverrideInFlightStateData(
                     // rollback to the src
                     return Optional.of(new ServiceUnitStateData(Owned, orphanData.sourceBroker(), true, nextVersionId));
                 } else {
-                    return getRollForwardStateData(serviceUnit, nextVersionId);
+                    return getRollForwardStateData(serviceUnit, orphanData.sourceBroker(), nextVersionId);
                 }
             }
             default: {

pulsar-broker/src/test/java/org/apache/pulsar/broker/loadbalance/extensions/ExtensibleLoadManagerImplTest.java

@@ -880,6 +880,51 @@ SplitDecision.Reason.Unknown, new AtomicLong(6))
         assertEquals(actual, expected);
     }
 
+    @Test
+    public void testDisableBroker() throws Exception {
+        // Test rollback to modular load manager.
+        ServiceConfiguration defaultConf = getDefaultConf();
+        defaultConf.setAllowAutoTopicCreation(true);
+        defaultConf.setForceDeleteNamespaceAllowed(true);
+        defaultConf.setLoadManagerClassName(ExtensibleLoadManagerImpl.class.getName());
+        defaultConf.setLoadBalancerSheddingEnabled(false);
+        try (var additionalPulsarTestContext = createAdditionalPulsarTestContext(defaultConf)) {
+            var pulsar3 = additionalPulsarTestContext.getPulsarService();
+            ExtensibleLoadManagerImpl ternaryLoadManager = spy((ExtensibleLoadManagerImpl)
+                    FieldUtils.readField(pulsar3.getLoadManager().get(), "loadManager", true));
+            String topic = "persistent://public/default/test";
+
+            String lookupResult1 = pulsar3.getAdminClient().lookups().lookupTopic(topic);
+            TopicName topicName = TopicName.get("test");
+            NamespaceBundle bundle = getBundleAsync(pulsar1, topicName).get();
+            if (!pulsar3.getBrokerServiceUrl().equals(lookupResult1)) {
+                admin.namespaces().unloadNamespaceBundle(topicName.getNamespace(), bundle.getBundleRange(),
+                        pulsar3.getLookupServiceAddress());
+                lookupResult1 = pulsar2.getAdminClient().lookups().lookupTopic(topic);
+            }
+            String lookupResult2 = pulsar1.getAdminClient().lookups().lookupTopic(topic);
+            String lookupResult3 = pulsar2.getAdminClient().lookups().lookupTopic(topic);
+
+            assertEquals(lookupResult1, pulsar3.getBrokerServiceUrl());
+            assertEquals(lookupResult1, lookupResult2);
+            assertEquals(lookupResult1, lookupResult3);
+
+
+            assertFalse(primaryLoadManager.checkOwnershipAsync(Optional.empty(), bundle).get());
+            assertFalse(secondaryLoadManager.checkOwnershipAsync(Optional.empty(), bundle).get());
+            assertTrue(ternaryLoadManager.checkOwnershipAsync(Optional.empty(), bundle).get());
+
+            ternaryLoadManager.disableBroker();
+
+            assertFalse(ternaryLoadManager.checkOwnershipAsync(Optional.empty(), bundle).get());
+            if (primaryLoadManager.checkOwnershipAsync(Optional.empty(), bundle).get()) {
+                assertFalse(secondaryLoadManager.checkOwnershipAsync(Optional.empty(), bundle).get());
+            } else {
+                assertTrue(secondaryLoadManager.checkOwnershipAsync(Optional.empty(), bundle).get());
+            }
+        }
+    }
+
     private static abstract class MockBrokerFilter implements BrokerFilter {
 
         @Override

pulsar-broker/src/test/java/org/apache/pulsar/broker/loadbalance/extensions/channel/ServiceUnitStateChannelTest.java

@@ -515,7 +515,7 @@ public void transferTestWhenDestBrokerFails()
 
         // recovered, check the monitor update state : Assigned -> Owned
         doReturn(CompletableFuture.completedFuture(Optional.of(lookupServiceAddress1)))
-                .when(loadManager).selectAsync(any());
+                .when(loadManager).selectAsync(any(), any());
         FieldUtils.writeDeclaredField(channel2, "producer", producer, true);
         FieldUtils.writeDeclaredField(channel1,
                 "inFlightStateWaitingTimeInMillis", 1 , true);
@@ -735,7 +735,7 @@ public void handleBrokerDeletionEventTest()
         var owner1 = channel1.getOwnerAsync(bundle1);
         var owner2 = channel2.getOwnerAsync(bundle2);
         doReturn(CompletableFuture.completedFuture(Optional.of(lookupServiceAddress2)))
-                .when(loadManager).selectAsync(any());
+                .when(loadManager).selectAsync(any(), any());
         assertTrue(owner1.get().isEmpty());
         assertTrue(owner2.get().isEmpty());
 
@@ -1101,7 +1101,7 @@ public void assignTestWhenDestBrokerProducerFails()
         FieldUtils.writeDeclaredField(channel2,
                 "inFlightStateWaitingTimeInMillis", 3 * 1000, true);
         doReturn(CompletableFuture.completedFuture(Optional.of(lookupServiceAddress2)))
-                .when(loadManager).selectAsync(any());
+                .when(loadManager).selectAsync(any(), any());
         channel1.publishAssignEventAsync(bundle, lookupServiceAddress2);
         // channel1 is broken. the assign won't be complete.
         waitUntilState(channel1, bundle);
@@ -1440,7 +1440,7 @@ public void testOverrideInactiveBrokerStateData()
 
         // test stable metadata state
         doReturn(CompletableFuture.completedFuture(Optional.of(lookupServiceAddress2)))
-                .when(loadManager).selectAsync(any());
+                .when(loadManager).selectAsync(any(), any());
         leaderChannel.handleMetadataSessionEvent(SessionReestablished);
         followerChannel.handleMetadataSessionEvent(SessionReestablished);
         FieldUtils.writeDeclaredField(leaderChannel, "lastMetadataSessionEventTimestamp",
@@ -1505,7 +1505,7 @@ public void testOverrideOrphanStateData()
 
         // test stable metadata state
         doReturn(CompletableFuture.completedFuture(Optional.of(lookupServiceAddress2)))
-                .when(loadManager).selectAsync(any());
+                .when(loadManager).selectAsync(any(), any());
         FieldUtils.writeDeclaredField(leaderChannel, "inFlightStateWaitingTimeInMillis",
                 -1, true);
         FieldUtils.writeDeclaredField(followerChannel, "inFlightStateWaitingTimeInMillis",