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

报错栈：

-- ::, ERROR [pool--thread-] threadpool.DefaultScheduler: : 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:)
        at org.apache.kylin.job.impl.threadpool.DefaultScheduler$JobRunner.run(DefaultScheduler.java:)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:)
        at java.lang.Thread.run(Thread.java:)
Caused by: org.apache.kylin.job.exception.ExecuteException: java.lang.NullPointerException
        at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:)
        at org.apache.kylin.job.execution.DefaultChainedExecutable.doWork(DefaultChainedExecutable.java:)
        at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:)
        ...  more
Caused by: java.lang.NullPointerException
        at org.apache.kylin.source.hive.CreateFlatHiveTableStep.getCubeSpecificConfig(CreateFlatHiveTableStep.java:)
        at org.apache.kylin.source.hive.CreateFlatHiveTableStep.doWork(CreateFlatHiveTableStep.java:)
        at org.apache.kylin.job.execution.AbstractExecutable.execute(AbstractExecutable.java:)
        ...  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