org.apache.spark.SparkException: A master URL must be set in your configuration

14/05/30 16:04:23 ERROR UserGroupInformation: PriviledgedActionException as:jnleec (auth:SIMPLE) cause:java.lang.reflect.InvocationTargetExceptionException in thread "Thread-3" java.lang.reflect.UndeclaredThrowableExceptionat org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1504)at org.apache.spark.deploy.SparkHadoopUtil.runAsUser(SparkHadoopUtil.scala:41)at org.apache.spark.deploy.yarn.ApplicationMaster$$anon$2.run(ApplicationMaster.scala:159)Caused by: java.lang.reflect.InvocationTargetExceptionat sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:606)at org.apache.spark.deploy.yarn.ApplicationMaster$$anon$2$$anonfun$run$1.apply$mcV$sp(ApplicationMaster.scala:165)at org.apache.spark.deploy.SparkHadoopUtil$$anon$1.run(SparkHadoopUtil.scala:42)at org.apache.spark.deploy.SparkHadoopUtil$$anon$1.run(SparkHadoopUtil.scala:41)at java.security.AccessController.doPrivileged(Native Method)at javax.security.auth.Subject.doAs(Subject.java:415)at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)... 2 moreCaused by: org.apache.spark.SparkException: A master URL must be set in your configurationat org.apache.spark.SparkContext.<init>(SparkContext.scala:113)at org.apache.spark.api.java.JavaSparkContext.<init>(JavaSparkContext.scala:47)at com.test.JavaSparkPi.main(JavaSparkPi.java:21)... 12 moreException in thread "main" java.lang.AssertionError: assertion failedat scala.Predef$.assert(Predef.scala:165)at org.apache.spark.deploy.yarn.ApplicationMaster.waitForSparkContextInitialized(ApplicationMaster.scala:201)at org.apache.spark.deploy.yarn.ApplicationMaster.run(ApplicationMaster.scala:105)at org.apache.spark.deploy.yarn.ApplicationMaster$.main(ApplicationMaster.scala:443)at org.apache.spark.deploy.yarn.ApplicationMaster.main(ApplicationMaster.scala)14/05/30 16:04:33 INFO ApplicationMaster: AppMaster received a signal.

错误原因，需要为spark设置master url

如果选择的部署模式是standalone且部署到你配置的这个集群上，可以指定 MASTER=spark://ubuntu:7070

下面解答spark在那里指定master URL的问题：
1.通过spark shell，执行后进入交互界面

MASTER=spark://IP:PORT ./bin/spark-shell

2.程序内指定（可以通过参数传入）

val conf = new SparkConf()             .setMaster(...)val sc = new SparkContext(conf)

传递给spark的master url可以有如下几种：

local 本地单线程
local[K] 本地多线程（指定K个内核）
local[*] 本地多线程（指定所有可用内核）
spark://HOST:PORT 连接到指定的 Spark standalone cluster master，需要指定端口。
mesos://HOST:PORT 连接到指定的 Mesos 集群，需要指定端口。
yarn-client客户端模式 连接到 YARN 集群。需要配置 HADOOP_CONF_DIR。
yarn-cluster集群模式 连接到 YARN 集群 。需要配置 HADOOP_CONF_DIR。