Spark Streaming kafka concurrentModificationException

Question

我使用的是Spark流媒体应用程序。应用程序使用直接流从Kafka topic (具有200个分区)中读取消息。应用程序偶尔会抛出ConcurrentModificationException->

java.util.ConcurrentModificationException: KafkaConsumer is not safe for multi-threaded access
at org.apache.kafka.clients.consumer.KafkaConsumer.acquire(KafkaConsumer.java:1431)
at org.apache.kafka.clients.consumer.KafkaConsumer.close(KafkaConsumer.java:1361)
at org.apache.spark.streaming.kafka010.CachedKafkaConsumer$$anon$1.removeEldestEntry(CachedKafkaConsumer.scala:128)
at java.util.LinkedHashMap.afterNodeInsertion(LinkedHashMap.java:299)
at java.util.HashMap.putVal(HashMap.java:663)
at java.util.HashMap.put(HashMap.java:611)
at org.apache.spark.streaming.kafka010.CachedKafkaConsumer$.get(CachedKafkaConsumer.scala:158)
at org.apache.spark.streaming.kafka010.KafkaRDD$KafkaRDDIterator.<init>(KafkaRDD.scala:211)
at org.apache.spark.streaming.kafka010.KafkaRDD.compute(KafkaRDD.scala:186)
at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87)
at org.apache.spark.scheduler.Task.run(Task.scala:99)
at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:282)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

我的spark集群有两个节点。Spark版本是2.1。应用程序运行两个执行器。从我从异常和kafka消费者代码中可以看出，似乎同一个kakfa消费者正在被两个线程使用。我不知道为什么两个线程访问同一个接收器。理想情况下，每个执行器都应该有一个独占的kafka接收器，由单个线程提供服务，该线程必须读取所有分配的分区的消息。从kafka读取的代码片段->

JavaInputDStream<ConsumerRecord<String, String>> consumerRecords = KafkaUtils.createDirectStream(
jssc,
LocationStrategies.PreferConsistent(),
ConsumerStrategies.<String, String>Subscribe(topics, kafkaParams));