bigdata - 在Kafka-storm中未能将偏移数据写入Zookeeper

Question

我当时正在设置一个 Storm 集群来计算实时趋势和其他统计信息，但是通过允许kafka-spout上次读取的偏移量(kafka-spout的源代码来自此)，我在向项目中引入“恢复”功能时遇到了一些问题。 https://github.com/apache/incubator-storm/tree/master/external/storm-kafka)要记住。我以这种方式启动kafka-spout:

BrokerHosts zkHost = new ZkHosts("localhost:2181");
SpoutConfig kafkaConfig = new SpoutConfig(zkHost, "test", "", "test");
kafkaConfig.forceFromStart = false;
KafkaSpout kafkaSpout = new KafkaSpout(kafkaConfig);
TopologyBuilder builder = new TopologyBuilder();
builder.setSpout("test" + "spout", kafkaSpout, ESConfig.spoutParallelism);

默认设置应该是这样做的，但是我认为在我的情况下不是这样，每次我启动项目时， PartitionManager都会尝试查找具有偏移量的文件，但没有发现任何东西:

2014-06-25 11:57:08 INFO  PartitionManager:73 - Read partition information from: /storm/partition_1  --> null
2014-06-25 11:57:08 INFO  PartitionManager:86 - No partition information found, using configuration to determine offset

然后，它开始从最新的可能偏移量开始读取。如果我的项目从未失败过，但又不是我想要的，那没关系。

我还进一步研究了 PartitionManager类，该类使用 Zkstate类从以下代码片段中编写了偏移量:

分区管理器

public void commit() {
    long lastCompletedOffset = lastCompletedOffset();
    if (_committedTo != lastCompletedOffset) {
        LOG.debug("Writing last completed offset (" + lastCompletedOffset + ") to ZK for " + _partition + " for topology: " + _topologyInstanceId);
        Map<Object, Object> data = (Map<Object, Object>) ImmutableMap.builder()
                .put("topology", ImmutableMap.of("id", _topologyInstanceId,
                        "name", _stormConf.get(Config.TOPOLOGY_NAME)))
                .put("offset", lastCompletedOffset)
                .put("partition", _partition.partition)
                .put("broker", ImmutableMap.of("host", _partition.host.host,
                        "port", _partition.host.port))
                .put("topic", _spoutConfig.topic).build();
        _state.writeJSON(committedPath(), data);

        _committedTo = lastCompletedOffset;
        LOG.debug("Wrote last completed offset (" + lastCompletedOffset + ") to ZK for " + _partition + " for topology: " + _topologyInstanceId);
    } else {
        LOG.debug("No new offset for " + _partition + " for topology: " + _topologyInstanceId);
    }
}

ZkState

public void writeBytes(String path, byte[] bytes) {
    try {
        if (_curator.checkExists().forPath(path) == null) {
            _curator.create()
                    .creatingParentsIfNeeded()
                    .withMode(CreateMode.PERSISTENT)
                    .forPath(path, bytes);
        } else {
            _curator.setData().forPath(path, bytes);
        }
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}

我可以看到，对于第一条消息， writeBytes方法进入 if块并尝试创建路径，然后对于第二条消息，它进入 else块，这似乎没问题。但是，当我再次启动该项目时，会出现与上述相同的消息。找不到 partition information。

Answer 1

我有同样的问题。原来，我是在本地模式下运行的，它使用的是内存中的Zookeeper，而不是Kafka使用的Zookeeper。

为了确保KafkaSpout不使用Storm的ZooKeeper作为存储偏移量的ZkState，除了SpoutConfig.zkServers之外，还需要设置SpoutConfig.zkPort，SpoutConfig.zkRoot和ZkHosts。例如

import org.apache.zookeeper.client.ConnectStringParser;
import storm.kafka.SpoutConfig;
import storm.kafka.ZkHosts;
import storm.kafka.KeyValueSchemeAsMultiScheme;

...

    final ConnectStringParser connectStringParser = new ConnectStringParser(zkConnectStr);
    final List<InetSocketAddress> serverInetAddresses = connectStringParser.getServerAddresses();
    final List<String> serverAddresses = new ArrayList<>(serverInetAddresses.size());
    final Integer zkPort = serverInetAddresses.get(0).getPort();
    for (InetSocketAddress serverInetAddress : serverInetAddresses) {
        serverAddresses.add(serverInetAddress.getHostName());
    }

    final ZkHosts zkHosts = new ZkHosts(zkConnectStr);
    zkHosts.brokerZkPath = kafkaZnode + zkHosts.brokerZkPath;

    final SpoutConfig spoutConfig = new SpoutConfig(zkHosts, inputTopic, kafkaZnode, kafkaConsumerGroup);
    spoutConfig.scheme = new KeyValueSchemeAsMultiScheme(inputKafkaKeyValueScheme);

    spoutConfig.zkServers = serverAddresses;
    spoutConfig.zkPort = zkPort;
    spoutConfig.zkRoot = kafkaZnode;