This topic describes how to run Spark Streaming jobs in Hadoop clusters of E-MapReduce to process data in Kafka clusters.

Programming reference

The Hadoop and Kafka clusters in E-MapReduce are based on completely open source software. Therefore, you can refer to the corresponding official documentation during your development.

Allow Spark Streaming jobs to access Kerberos Kafka clusters

E-MapReduce allows you to create Kafka clusters based on Kerberos authentication. Jobs in Hadoop clusters can access Kerberos Kafka clusters in two ways:

  • Non-Kerberos Hadoop cluster: Provide the kafka_client_jaas.conf file for Kerberos authentication of Kafka clusters.
  • Kerberos Hadoop cluster: Cross-domain communication based on Kerberos clusters. Provide the kafka_client_jaas.conf file for Kerberos authentication of Hadoop clusters.

Both methods require that you provide the kafka_client_jaas.conf file for Kerberos authentication when you run a job.

The file format of kafka_client_jaas.conf is as follows: 
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    storeKey=true
    serviceName="kafka"
    keyTab="/path/to/kafka.keytab"
    principal="kafka/emr-header-1.cluster-12345@EMR. 12345. COM";
};

For more information about how to obtain the keytab file, see Kerberos authentication in the User Guide.

Allow Spark Streaming jobs to access Kerberos Kafka clusters

When you run Spark Streaming jobs to access Kerberos Kafka clusters, you can provide the kafka_client_jaas.conf file and the kafka.keytab file as needed in the spark-submit command line parameters. 
spark-submit --conf spark.driver.extraJavaOptions=-Djava.security.auth.login.config={{PWD}}/kafka_client_jaas.conf --conf spark.executor.extraJavaOptions=-Djava.security.auth.login.config={{PWD}}/kafka_client_jaas.conf --files /local/path/to/kafka_client_jaas.conf,/local/path/to/kafka.keytab --class xx.xx.xx.KafkaSample --num-executors 2 --executor-cores 2 --executor-memory 1g --master yarn-cluster xxx.jar arg1 arg2 arg3
Note that in the kafka_client_jaas.conf file, the keytab file path must be a relative path. Make sure that you configure the path in the following format: 
KafkaClient {
    com.sun.security.auth.module.Krb5LoginModule required
    useKeyTab=true
    storeKey=true
    serviceName="kafka"
    keyTab="kafka.keytab"
    principal="kafka/emr-header-1.cluster-12345@EMR. 12345. COM";
};