Amazon MSK 默认配置和交易发布问题

Question

最近我们开始对我们的 Kafka 连接器进行一些测试，以连接到亚马逊的托管 Kafka 服务 MSK。发布记录似乎工作正常，但是不当启用交易时。

我们的集群由 2 个使用默认 MSK 配置的代理组成（因为我们有 2 个区域）。我们正在使用以下属性创建 Java Kafka 生产者：

bootstrap.servers=x.us-east-1.amazonaws.com:9094,y.us-east-1.amazonaws.com:9094
client.id=kafkautil
max.block.ms=5000
request.timeout.ms=5000
security.protocol=SSL
transactional.id=transactions

然而，当生产者以启用事务的 transactional.id 设置启动时，initTransactions() 方法挂起：

producer = new KafkaProducer<Object, Object>(kafkaProperties);
if (kafkaProperties.containsKey(ProducerConfig.TRANSACTIONAL_ID_CONFIG)) {
    // this hangs
    producer.initTransactions();
}

查看日志输出，我们看到以下流，它似乎从未超时。

TransactionManager - Enqueuing transactional request (type=FindCoordinatorRequest,
    coordinatorKey=y, coordinatorType=TRANSACTION)
TransactionManager - Request (type=FindCoordinatorRequest, coordinatorKey=y,
    coordinatorType=TRANSACTION) dequeued for sending
NetworkClient - Found least loaded node z:9094 (id: -2 rack: null) connected with no
    in-flight requests
Sender - Sending transactional request (type=FindCoordinatorRequest, coordinatorKey=y,
    coordinatorType=TRANSACTION) to node z (id: -2 rack: null)
NetworkClient - Sending FIND_COORDINATOR {coordinator_key=y,coordinator_type=1} with
    correlation id 424 to node -2
NetworkClient - Completed receive from node -2 for FIND_COORDINATOR with
    correlation id 424, received {throttle_time_ms=0,error_code=15,error_message=null,
    coordinator={node_id=-1,host=,port=-1}}
TransactionManager LogContext.java:129 - Received transactional response
    FindCoordinatorResponse(throttleTimeMs=0, errorMessage='null', 
    error=COORDINATOR_NOT_AVAILABLE, node=:-1 (id: -1 rack: null)) for request
    (type=FindCoordinatorRequest, coordinatorKey=xxx, coordinatorType=TRANSACTION)

据我所知，代理可用并且 bootstrap.servers 属性中的每个主机都可用。如果我连接到它们中的每一个并在没有交易的情况下发布，那么它就可以工作。

知道我们缺少什么吗？

Answer 1

However when the producer was started with the transactional.id setting which enables transactions, the initTransactions() method hangs:

事实证明这是默认 AWS MSK 属性和代理数量的问题。如果您创建的 Kafka 集群少于 3 个代理，则需要调整以下设置。

以下设置应该设置（我认为）到经纪人的数量：

Property	Kafka Default	AWS Default	Description
default.replication.factor	1	3	Default replication factors for automatically created topics.
min.insync.replicas	1	2	Minimum number of replicas that must acknowledge a write for the write to be considered successful
offsets.topic.replication.factor	3	3	Internal topic that shares offsets on topics.
transaction.state.log.replication.factor	3	3	Replication factor for the transaction topic.

这是 Kafka docs on broker properties。

因为我们有 2 个经纪人，所以我们最终得到：

default.replication.factor=2
min.insync.replicas=2
offsets.topic.replication.factor=2
transaction.state.log.replication.factor=2

这似乎解决了问题。恕我直言，这是 AWS MSK 和默认配置的真正问题。他们需要自动生成默认配置并根据集群中代理的数量进行调整。

Amazon MSK 默认配置和交易发布问题

Problems with Amazon MSK default configuration and publishing with transactions

transactions

apache-kafka

aws-msk