解决kylin build cube第一步报错：java.lang.NullPointerException

报错栈：

2017-06-19 10:27:35,757 ERROR [pool-9-thread-4] threadpool.DefaultScheduler:140 : ExecuteException job:933bc47a-302c-48fa-8ec9-ae8730057175
org.apache.kylin.job.exception.ExecuteException: org.apache.kylin.job.exception.ExecuteException: java.lang.NullPointerException
        at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:123)
        at org.apache.kylin.job.impl.threadpool.DefaultScheduler$JobRunner.run(DefaultScheduler.java:136)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at java.lang.Thread.run(Thread.java:745)
Caused by: org.apache.kylin.job.exception.ExecuteException: java.lang.NullPointerException
        at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:123)
        at org.apache.kylin.job.execution.DefaultChainedExecutable.doWork(DefaultChainedExecutable.java:57)
        at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:113)
        ... 4 more
Caused by: java.lang.NullPointerException
        at org.apache.kylin.source.hive.CreateFlatHiveTableStep.getCubeSpecificConfig(CreateFlatHiveTableStep.java:100)
        at org.apache.kylin.source.hive.CreateFlatHiveTableStep.doWork(CreateFlatHiveTableStep.java:105)
        at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:113)
        ... 6 more

原因：kylin集群的build server没有获取到最新meta导致

解决方法：reload metadata