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[fix][broker] timeout when broker registry hangs and monitor broker r…
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…egistry (ExtensibleLoadManagerImpl only) (apache#23382)
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@heesung-sn
heesung-sn authored Oct 3, 2024
1 parent ab684a0 commit eee9283
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Showing 10 changed files with 299 additions and 50 deletions.
11 changes: 9 additions & 2 deletions pulsar-broker/src/main/java/org/apache/pulsar/broker/admin/impl/BrokersBase.java
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Original file line number Diff line number Diff line change
Expand Up @@ -48,6 +48,7 @@
import javax.ws.rs.container.Suspended;
import javax.ws.rs.core.Response;
import javax.ws.rs.core.Response.Status;
import org.apache.commons.lang.StringUtils;
import org.apache.pulsar.PulsarVersion;
import org.apache.pulsar.broker.PulsarServerException;
import org.apache.pulsar.broker.PulsarService.State;
Expand Down Expand Up @@ -368,20 +369,26 @@ public void isReady(@Suspended AsyncResponse asyncResponse) {
@ApiOperation(value = "Run a healthCheck against the broker")
@ApiResponses(value = {
@ApiResponse(code = 200, message = "Everything is OK"),
@ApiResponse(code = 307, message = "Current broker is not the target broker"),
@ApiResponse(code = 403, message = "Don't have admin permission"),
@ApiResponse(code = 404, message = "Cluster doesn't exist"),
@ApiResponse(code = 500, message = "Internal server error")})
public void healthCheck(@Suspended AsyncResponse asyncResponse,
@ApiParam(value = "Topic Version")
@QueryParam("topicVersion") TopicVersion topicVersion) {
@QueryParam("topicVersion") TopicVersion topicVersion,
@QueryParam("brokerId") String brokerId) {
validateSuperUserAccessAsync()
.thenAccept(__ -> checkDeadlockedThreads())
.thenCompose(__ -> maybeRedirectToBroker(
StringUtils.isBlank(brokerId) ? pulsar().getBrokerId() : brokerId))
.thenCompose(__ -> internalRunHealthCheck(topicVersion))
.thenAccept(__ -> {
LOG.info("[{}] Successfully run health check.", clientAppId());
asyncResponse.resume(Response.ok("ok").build());
}).exceptionally(ex -> {
LOG.error("[{}] Fail to run health check.", clientAppId(), ex);
if (!isRedirectException(ex)) {
LOG.error("[{}] Fail to run health check.", clientAppId(), ex);
}
resumeAsyncResponseExceptionally(asyncResponse, ex);
return null;
});
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5 changes: 5 additions & 0 deletions ...-broker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/BrokerRegistry.java
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Expand Up @@ -48,6 +48,11 @@ public interface BrokerRegistry extends AutoCloseable {
*/
boolean isStarted();

/**
* Return the broker has been registered.
*/
boolean isRegistered();

/**
* Register local broker to metadata store.
*/
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69 changes: 57 additions & 12 deletions ...ker/src/main/java/org/apache/pulsar/broker/loadbalance/extensions/BrokerRegistryImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,8 @@
@Slf4j
public class BrokerRegistryImpl implements BrokerRegistry {

private static final int MAX_REGISTER_RETRY_DELAY_IN_MILLIS = 1000;

private final PulsarService pulsar;

private final ServiceConfiguration conf;
Expand All @@ -77,10 +79,11 @@ protected enum State {
@VisibleForTesting
final AtomicReference<State> state = new AtomicReference<>(State.Init);

public BrokerRegistryImpl(PulsarService pulsar) {
@VisibleForTesting
BrokerRegistryImpl(PulsarService pulsar, MetadataCache<BrokerLookupData> brokerLookupDataMetadataCache) {
this.pulsar = pulsar;
this.conf = pulsar.getConfiguration();
this.brokerLookupDataMetadataCache = pulsar.getLocalMetadataStore().getMetadataCache(BrokerLookupData.class);
this.brokerLookupDataMetadataCache = brokerLookupDataMetadataCache;
this.scheduler = pulsar.getLoadManagerExecutor();
this.listeners = new ArrayList<>();
this.brokerIdKeyPath = keyPath(pulsar.getBrokerId());
Expand All @@ -99,6 +102,10 @@ public BrokerRegistryImpl(PulsarService pulsar) {
pulsar.getConfig().lookupProperties());
}

public BrokerRegistryImpl(PulsarService pulsar) {
this(pulsar, pulsar.getLocalMetadataStore().getMetadataCache(BrokerLookupData.class));
}

@Override
public synchronized void start() throws PulsarServerException {
if (!this.state.compareAndSet(State.Init, State.Started)) {
Expand All @@ -118,6 +125,12 @@ public boolean isStarted() {
return state == State.Started || state == State.Registered;
}

@Override
public boolean isRegistered() {
final var state = this.state.get();
return state == State.Registered;
}

@Override
public CompletableFuture<Void> registerAsync() {
final var state = this.state.get();
Expand All @@ -127,12 +140,35 @@ public CompletableFuture<Void> registerAsync() {
}
log.info("[{}] Started registering self to {} (state: {})", getBrokerId(), brokerIdKeyPath, state);
return brokerLookupDataMetadataCache.put(brokerIdKeyPath, brokerLookupData, EnumSet.of(CreateOption.Ephemeral))
.thenAccept(__ -> {
this.state.set(State.Registered);
log.info("[{}] Finished registering self", getBrokerId());
.orTimeout(pulsar.getConfiguration().getMetadataStoreOperationTimeoutSeconds(), TimeUnit.SECONDS)
.whenComplete((__, ex) -> {
if (ex == null) {
this.state.set(State.Registered);
log.info("[{}] Finished registering self", getBrokerId());
} else {
log.error("[{}] Failed registering self", getBrokerId(), ex);
}
});
}

private void doRegisterAsyncWithRetries(int retry, CompletableFuture<Void> future) {
pulsar.getExecutor().schedule(() -> {
registerAsync().whenComplete((__, e) -> {
if (e != null) {
doRegisterAsyncWithRetries(retry + 1, future);
} else {
future.complete(null);
}
});
}, Math.min(MAX_REGISTER_RETRY_DELAY_IN_MILLIS, retry * retry * 50), TimeUnit.MILLISECONDS);
}

private CompletableFuture<Void> registerAsyncWithRetries() {
var retryFuture = new CompletableFuture<Void>();
doRegisterAsyncWithRetries(0, retryFuture);
return retryFuture;
}

@Override
public synchronized void unregister() throws MetadataStoreException {
if (state.compareAndSet(State.Registered, State.Unregistering)) {
Expand Down Expand Up @@ -219,17 +255,26 @@ private void handleMetadataStoreNotification(Notification t) {
// The registered node is an ephemeral node that could be deleted when the metadata store client's session
// is expired. In this case, we should register again.
final var brokerId = t.getPath().substring(LOADBALANCE_BROKERS_ROOT.length() + 1);

CompletableFuture<Void> register;
if (t.getType() == NotificationType.Deleted && getBrokerId().equals(brokerId)) {
registerAsync();
}
if (listeners.isEmpty()) {
return;
this.state.set(State.Started);
register = registerAsyncWithRetries();
} else {
register = CompletableFuture.completedFuture(null);
}
this.scheduler.submit(() -> {
for (BiConsumer<String, NotificationType> listener : listeners) {
listener.accept(brokerId, t.getType());
// Make sure to run the listeners after re-registered.
register.thenAccept(__ -> {
if (listeners.isEmpty()) {
return;
}
this.scheduler.submit(() -> {
for (BiConsumer<String, NotificationType> listener : listeners) {
listener.accept(brokerId, t.getType());
}
});
});

} catch (RejectedExecutionException e) {
// Executor is shutting down
}
Expand Down
18 changes: 17 additions & 1 deletion .../main/java/org/apache/pulsar/broker/loadbalance/extensions/ExtensibleLoadManagerImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -35,8 +35,10 @@
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Function;
Expand Down Expand Up @@ -987,8 +989,12 @@ protected void monitor() {
return;
}

// Monitor broker registry
// Periodically check the broker registry in case metadata store fails.
validateBrokerRegistry();

// Monitor role
// Periodically check the role in case ZK watcher fails.
// Periodically check the role in case metadata store fails.
var isChannelOwner = serviceUnitStateChannel.isChannelOwner();
if (isChannelOwner) {
// System topic config might fail due to the race condition
Expand Down Expand Up @@ -1087,5 +1093,15 @@ private boolean isPersistentSystemTopicUsed() {
.equals(pulsar.getConfiguration().getLoadManagerServiceUnitStateTableViewClassName());
}

private void validateBrokerRegistry()
throws ExecutionException, InterruptedException, TimeoutException {
var timeout = pulsar.getConfiguration().getMetadataStoreOperationTimeoutSeconds();
var lookup = brokerRegistry.lookupAsync(brokerRegistry.getBrokerId()).get(timeout, TimeUnit.SECONDS);
if (lookup.isEmpty()) {
log.warn("Found this broker:{} has not registered yet. Trying to register it",
brokerRegistry.getBrokerId());
brokerRegistry.registerAsync().get(timeout, TimeUnit.SECONDS);
}
}

}
98 changes: 85 additions & 13 deletions .../org/apache/pulsar/broker/loadbalance/extensions/channel/ServiceUnitStateChannelImpl.java
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Original file line number Diff line number Diff line change
Expand Up @@ -86,11 +86,13 @@
import org.apache.pulsar.broker.namespace.LookupOptions;
import org.apache.pulsar.broker.namespace.NamespaceService;
import org.apache.pulsar.broker.service.BrokerServiceException;
import org.apache.pulsar.client.admin.PulsarAdmin;
import org.apache.pulsar.client.api.Schema;
import org.apache.pulsar.common.naming.NamespaceBundle;
import org.apache.pulsar.common.naming.NamespaceBundleFactory;
import org.apache.pulsar.common.naming.NamespaceBundleSplitAlgorithm;
import org.apache.pulsar.common.naming.NamespaceBundles;
import org.apache.pulsar.common.naming.TopicVersion;
import org.apache.pulsar.common.stats.Metrics;
import org.apache.pulsar.common.util.FutureUtil;
import org.apache.pulsar.common.util.Reflections;
Expand All @@ -108,13 +110,16 @@ public class ServiceUnitStateChannelImpl implements ServiceUnitStateChannel {
private static final long MIN_CLEAN_UP_DELAY_TIME_IN_SECS = 0; // 0 secs to clean immediately
private static final long MAX_CHANNEL_OWNER_ELECTION_WAITING_TIME_IN_SECS = 10;
private static final long MAX_OWNED_BUNDLE_COUNT_DELAY_TIME_IN_MILLIS = 10 * 60 * 1000;
private static final long MAX_BROKER_HEALTH_CHECK_RETRY = 3;
private static final long MAX_BROKER_HEALTH_CHECK_DELAY_IN_MILLIS = 1000;
private final PulsarService pulsar;
private final ServiceConfiguration config;
private final Schema<ServiceUnitStateData> schema;
private final Map<String, CompletableFuture<String>> getOwnerRequests;
private final String brokerId;
private final Map<String, CompletableFuture<Void>> cleanupJobs;
private final StateChangeListeners stateChangeListeners;

private BrokerRegistry brokerRegistry;
private LeaderElectionService leaderElectionService;

Expand Down Expand Up @@ -350,6 +355,11 @@ protected LeaderElectionService getLeaderElectionService() {
.get().getLeaderElectionService();
}

@VisibleForTesting
protected PulsarAdmin getPulsarAdmin() throws PulsarServerException {
return pulsar.getAdminClient();
}

@Override
public synchronized void close() throws PulsarServerException {
channelState = Closed;
Expand Down Expand Up @@ -448,6 +458,14 @@ private CompletableFuture<Optional<String>> getActiveOwnerAsync(
String serviceUnit,
ServiceUnitState state,
Optional<String> owner) {

// If this broker's registry does not exist(possibly suffering from connecting to the metadata store),
// we return the owner without its activeness check.
// This broker tries to serve lookups on a best efforts basis when metadata store connection is unstable.
if (!brokerRegistry.isRegistered()) {
return CompletableFuture.completedFuture(owner);
}

return dedupeGetOwnerRequest(serviceUnit)
.thenCompose(newOwner -> {
if (newOwner == null) {
Expand Down Expand Up @@ -1255,19 +1273,25 @@ private MetadataState getMetadataState() {
}

private void handleBrokerCreationEvent(String broker) {
CompletableFuture<Void> future = cleanupJobs.remove(broker);
if (future != null) {
future.cancel(false);
totalInactiveBrokerCleanupCancelledCnt++;
log.info("Successfully cancelled the ownership cleanup for broker:{}."
+ " Active cleanup job count:{}",
broker, cleanupJobs.size());
} else {
if (debug()) {
log.info("No needs to cancel the ownership cleanup for broker:{}."
+ " There was no scheduled cleanup job. Active cleanup job count:{}",
broker, cleanupJobs.size());
}

if (!cleanupJobs.isEmpty() && cleanupJobs.containsKey(broker)) {
healthCheckBrokerAsync(broker)
.thenAccept(__ -> {
CompletableFuture<Void> future = cleanupJobs.remove(broker);
if (future != null) {
future.cancel(false);
totalInactiveBrokerCleanupCancelledCnt++;
log.info("Successfully cancelled the ownership cleanup for broker:{}."
+ " Active cleanup job count:{}",
broker, cleanupJobs.size());
} else {
if (debug()) {
log.info("No needs to cancel the ownership cleanup for broker:{}."
+ " There was no scheduled cleanup job. Active cleanup job count:{}",
broker, cleanupJobs.size());
}
}
});
}
}

Expand Down Expand Up @@ -1431,6 +1455,37 @@ private void waitForCleanups(String broker, boolean excludeSystemTopics, int max
System.currentTimeMillis() - started);
}

private CompletableFuture<Void> healthCheckBrokerAsync(String brokerId) {
CompletableFuture<Void> future = new CompletableFuture<>();
doHealthCheckBrokerAsyncWithRetries(brokerId, 0, future);
return future;
}

private void doHealthCheckBrokerAsyncWithRetries(String brokerId, int retry, CompletableFuture<Void> future) {
try {
var admin = getPulsarAdmin();
admin.brokers().healthcheckAsync(TopicVersion.V2, Optional.of(brokerId))
.whenComplete((__, e) -> {
if (e == null) {
log.info("Completed health-check broker :{}", brokerId, e);
future.complete(null);
return;
}
if (retry == MAX_BROKER_HEALTH_CHECK_RETRY) {
log.error("Failed health-check broker :{}", brokerId, e);
future.completeExceptionally(FutureUtil.unwrapCompletionException(e));
} else {
pulsar.getExecutor()
.schedule(() -> doHealthCheckBrokerAsyncWithRetries(brokerId, retry + 1, future),
Math.min(MAX_BROKER_HEALTH_CHECK_DELAY_IN_MILLIS, retry * retry * 50),
MILLISECONDS);
}
});
} catch (PulsarServerException e) {
future.completeExceptionally(e);
}
}

private synchronized void doCleanup(String broker, boolean gracefully) {
try {
if (getChannelOwnerAsync().get(MAX_CHANNEL_OWNER_ELECTION_WAITING_TIME_IN_SECS, TimeUnit.SECONDS)
Expand All @@ -1444,6 +1499,23 @@ private synchronized void doCleanup(String broker, boolean gracefully) {
return;
}

// if not gracefully, verify the broker is inactive by health-check.
if (!gracefully) {
try {
healthCheckBrokerAsync(broker).get(
pulsar.getConfiguration().getMetadataStoreOperationTimeoutSeconds(), SECONDS);
log.warn("Found that the broker to clean is healthy. Skip the broker:{}'s orphan bundle cleanup",
broker);
return;
} catch (Exception e) {
if (debug()) {
log.info("Failed to check broker:{} health", broker, e);
}
log.info("Checked the broker:{} health. Continue the orphan bundle cleanup", broker);
}
}


long startTime = System.nanoTime();
log.info("Started ownership cleanup for the inactive broker:{}", broker);
int orphanServiceUnitCleanupCnt = 0;
Expand Down
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