Examples with BrokerFilter org.apache.pulsar.broker.loadbalance.BrokerFilter used on opensource projects

Example 1 with BrokerFilter

use of org.apache.pulsar.broker.loadbalance.BrokerFilter in project incubator-pulsar by apache.

the class ModularLoadManagerImpl method selectBrokerForAssignment.

/**
 * As the leader broker, find a suitable broker for the assignment of the given bundle.
 *
 * @param serviceUnit
 *            ServiceUnitId for the bundle.
 * @return The name of the selected broker, as it appears on ZooKeeper.
 */
@Override
public Optional<String> selectBrokerForAssignment(final ServiceUnitId serviceUnit) {
    // Use brokerCandidateCache as a lock to reduce synchronization.
    synchronized (brokerCandidateCache) {
        final String bundle = serviceUnit.toString();
        if (preallocatedBundleToBroker.containsKey(bundle)) {
            // If the given bundle is already in preallocated, return the selected broker.
            return Optional.of(preallocatedBundleToBroker.get(bundle));
        }
        final BundleData data = loadData.getBundleData().computeIfAbsent(bundle, key -> getBundleDataOrDefault(bundle));
        brokerCandidateCache.clear();
        LoadManagerShared.applyNamespacePolicies(serviceUnit, policies, brokerCandidateCache, getAvailableBrokers(), brokerTopicLoadingPredicate);
        // filter brokers which owns topic higher than threshold
        LoadManagerShared.filterBrokersWithLargeTopicCount(brokerCandidateCache, loadData, conf.getLoadBalancerBrokerMaxTopics());
        // distribute namespaces to domain and brokers according to anti-affinity-group
        LoadManagerShared.filterAntiAffinityGroupOwnedBrokers(pulsar, serviceUnit.toString(), brokerCandidateCache, brokerToNamespaceToBundleRange, brokerToFailureDomainMap);
        // distribute bundles evenly to candidate-brokers
        LoadManagerShared.removeMostServicingBrokersForNamespace(serviceUnit.toString(), brokerCandidateCache, brokerToNamespaceToBundleRange);
        log.info("{} brokers being considered for assignment of {}", brokerCandidateCache.size(), bundle);
        // Use the filter pipeline to finalize broker candidates.
        try {
            for (BrokerFilter filter : filterPipeline) {
                filter.filter(brokerCandidateCache, data, loadData, conf);
            }
        } catch (BrokerFilterException x) {
            // restore the list of brokers to the full set
            LoadManagerShared.applyNamespacePolicies(serviceUnit, policies, brokerCandidateCache, getAvailableBrokers(), brokerTopicLoadingPredicate);
        }
        if (brokerCandidateCache.isEmpty()) {
            // restore the list of brokers to the full set
            LoadManagerShared.applyNamespacePolicies(serviceUnit, policies, brokerCandidateCache, getAvailableBrokers(), brokerTopicLoadingPredicate);
        }
        // Choose a broker among the potentially smaller filtered list, when possible
        Optional<String> broker = placementStrategy.selectBroker(brokerCandidateCache, data, loadData, conf);
        if (log.isDebugEnabled()) {
            log.debug("Selected broker {} from candidate brokers {}", broker, brokerCandidateCache);
        }
        if (!broker.isPresent()) {
            // No brokers available
            return broker;
        }
        final double overloadThreshold = conf.getLoadBalancerBrokerOverloadedThresholdPercentage() / 100.0;
        final double maxUsage = loadData.getBrokerData().get(broker.get()).getLocalData().getMaxResourceUsage();
        if (maxUsage > overloadThreshold) {
            // All brokers that were in the filtered list were overloaded, so check if there is a better broker
            LoadManagerShared.applyNamespacePolicies(serviceUnit, policies, brokerCandidateCache, getAvailableBrokers(), brokerTopicLoadingPredicate);
            broker = placementStrategy.selectBroker(brokerCandidateCache, data, loadData, conf);
        }
        // Add new bundle to preallocated.
        loadData.getBrokerData().get(broker.get()).getPreallocatedBundleData().put(bundle, data);
        preallocatedBundleToBroker.put(bundle, broker.get());
        final String namespaceName = LoadManagerShared.getNamespaceNameFromBundleName(bundle);
        final String bundleRange = LoadManagerShared.getBundleRangeFromBundleName(bundle);
        brokerToNamespaceToBundleRange.get(broker.get()).computeIfAbsent(namespaceName, k -> new HashSet<>()).add(bundleRange);
        return broker;
    }
}