Kafka Broker的问题- UnknownServerException

Question

我们的应用程序使用springBootVersion = 2.0.4.RELEASE和compile('io.projectreactor.kafka:reactor-kafka:1.0.1.RELEASE')依赖项。

我们拥有的Kafka代理的版本是1.0.1。

当我们通过创建reactor.kafka.sender.SenderRecord间歇性地向Kafka发送消息时，在响应Kafka时，当查找reactor.kafka.sender.SenderResult.exception()时，我们有

异常中填充的java.lang.RuntimeException: org.apache.kafka.common.errors.UnknownServerException: The server experienced an unexpected error when processing the request。

在重试几次后，消息成功通过。

在代理日志中，以下错误被多次打印，没有任何堆栈跟踪

[2019-02-08 15:43:07,501] ERROR [ReplicaManager broker=3] Error processing append operation on partition price-promotions-local-event-0 (kafka.server.ReplicaManager)

其中price-promotions-local-event是我们的主题。

我已经在网上看过了，但是没有明确的解决方案或方法来分类这个问题，非常感谢你的帮助。

Answer 1

在进一步的调查中，我们可以获得代理日志上的堆栈跟踪，如下所示

ERROR [ReplicaManager broker=1] Error processing append operation on partition price-promotions-local-event-0 (kafka.server.ReplicaManager)
java.lang.IllegalArgumentException: Magic v1 does not support record headers
    at org.apache.kafka.common.record.MemoryRecordsBuilder.appendWithOffset(MemoryRecordsBuilder.java:403)
    at org.apache.kafka.common.record.MemoryRecordsBuilder.appendWithOffset(MemoryRecordsBuilder.java:442)
    at org.apache.kafka.common.record.MemoryRecordsBuilder.appendWithOffset(MemoryRecordsBuilder.java:595)
    at kafka.log.LogValidator$.$anonfun$convertAndAssignOffsetsNonCompressed$2(LogValidator.scala:138)
    at kafka.log.LogValidator$.$anonfun$convertAndAssignOffsetsNonCompressed$2$adapted(LogValidator.scala:136)
    at scala.collection.Iterator.foreach(Iterator.scala:929)
    at scala.collection.Iterator.foreach$(Iterator.scala:929)
    at scala.collection.AbstractIterator.foreach(Iterator.scala:1417)
    at scala.collection.IterableLike.foreach(IterableLike.scala:71)
    at scala.collection.IterableLike.foreach$(IterableLike.scala:70)
    at scala.collection.AbstractIterable.foreach(Iterable.scala:54)
    at kafka.log.LogValidator$.$anonfun$convertAndAssignOffsetsNonCompressed$1(LogValidator.scala:136)
    at kafka.log.LogValidator$.$anonfun$convertAndAssignOffsetsNonCompressed$1$adapted(LogValidator.scala:133)
    at scala.collection.Iterator.foreach(Iterator.scala:929)
    at scala.collection.Iterator.foreach$(Iterator.scala:929)
    at scala.collection.AbstractIterator.foreach(Iterator.scala:1417)
    at scala.collection.IterableLike.foreach(IterableLike.scala:71)
    at scala.collection.IterableLike.foreach$(IterableLike.scala:70)
    at scala.collection.AbstractIterable.foreach(Iterable.scala:54)
    at kafka.log.LogValidator$.convertAndAssignOffsetsNonCompressed(LogValidator.scala:133)
    at kafka.log.LogValidator$.validateMessagesAndAssignOffsets(LogValidator.scala:64)
    at kafka.log.Log.liftedTree1$1(Log.scala:654)
    at kafka.log.Log.$anonfun$append$2(Log.scala:642)
    at kafka.log.Log.maybeHandleIOException(Log.scala:1669)
    at kafka.log.Log.append(Log.scala:624)
    at kafka.log.Log.appendAsLeader(Log.scala:597)
    at kafka.cluster.Partition.$anonfun$appendRecordsToLeader$1(Partition.scala:499)
    at kafka.utils.CoreUtils$.inLock(CoreUtils.scala:217)
    at kafka.utils.CoreUtils$.inReadLock(CoreUtils.scala:223)
    at kafka.cluster.Partition.appendRecordsToLeader(Partition.scala:487)
    at kafka.server.ReplicaManager.$anonfun$appendToLocalLog$2(ReplicaManager.scala:724)
    at scala.collection.TraversableLike.$anonfun$map$1(TraversableLike.scala:234)
    at scala.collection.mutable.HashMap.$anonfun$foreach$1(HashMap.scala:138)
    at scala.collection.mutable.HashTable.foreachEntry(HashTable.scala:236)
    at scala.collection.mutable.HashTable.foreachEntry$(HashTable.scala:229)
    at scala.collection.mutable.HashMap.foreachEntry(HashMap.scala:40)
    at scala.collection.mutable.HashMap.foreach(HashMap.scala:138)
    at scala.collection.TraversableLike.map(TraversableLike.scala:234)
    at scala.collection.TraversableLike.map$(TraversableLike.scala:227)
    at scala.collection.AbstractTraversable.map(Traversable.scala:104)
    at kafka.server.ReplicaManager.appendToLocalLog(ReplicaManager.scala:708)
    at kafka.server.ReplicaManager.appendRecords(ReplicaManager.scala:459)
    at kafka.server.KafkaApis.handleProduceRequest(KafkaApis.scala:465)
    at kafka.server.KafkaApis.handle(KafkaApis.scala:98)
    at kafka.server.KafkaRequestHandler.run(KafkaRequestHandler.scala:65)
    at java.lang.Thread.run(Thread.java:748)

从org.apache.kafka:kafka-clients:1.0.2中提供的类文件MemoryRecordsBuilder中，我们可以看到下面抛出此IllegalArgumentException的位置。

if (magic < RecordBatch.MAGIC_VALUE_V2 && headers != null && headers.length > 0)
  throw new IllegalArgumentException("Magic v" + magic + " does not support record headers");

所以，在ProducerRecord中设置了导致问题的标题，在打印ProducerRecord时，我们发现这些标题是由AppDynamics添加的--一个“singularityheader”被添加到Kafka Produced记录中。

c.t.a.p.i.m.i.KafkaProducerInterceptor   : The kafka Interceptor ProducerRecord header:: RecordHeader(key = singularityheader, value = [110, 111, 116, 120, 100, 101, 116, 101, 99, 116, 61, 116, 114, 117, 101, 42, 99, 116, 114, 108, 103, 117, 105, 100, 61, 49, 53, 53, 49, 51, 55, 51, 54, 57, 49, 42, 97, 112, 112, 73, 100, 61, 55, 49, 48, 51, 50, 42, 110, 111, 100, 101, 105, 100, 61, 49, 51, 53, 55, 53, 51, 53])

更多阅读https://developer.ibm.com/messaging/2018/07/10/additional-rfh-header-added-appdynamics-monitor-agent-tool/

因此，我们在拦截器中显式地将头设置为null，这解决了这个问题。