解决时区导致druid任务构建失败的问题：No buckets?? seems there is no data to index.

===== update 2017-07-12 begin =====

No Buckets 的主要原因是: load batch data 的时候，intervals 的范围小于被上传数据的时间范围

===== update 2017-07-12  end   =====

Error stack as fllow：

2017-07-10T08:41:36,134 ERROR [task-runner-0-priority-0] io.druid.indexing.overlord.ThreadPoolTaskRunner - Exception while running task[HadoopIndexTask{id=index_hadoop_pageviews_2017-07-10T08:40:32.650Z, type=index_hadoop, dataSource=pageviews}]
java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
at com.google.common.base.Throwables.propagate(Throwables.java:160) ~[guava-16.0.1.jar:?]
at io.druid.indexing.common.task.HadoopTask.invokeForeignLoader(HadoopTask.java:204) ~[druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexing.common.task.HadoopIndexTask.run(HadoopIndexTask.java:208) ~[druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexing.overlord.ThreadPoolTaskRunner$ThreadPoolTaskRunnerCallable.call(ThreadPoolTaskRunner.java:436) [druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexing.overlord.ThreadPoolTaskRunner$ThreadPoolTaskRunnerCallable.call(ThreadPoolTaskRunner.java:408) [druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_131]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_131]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_131]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_131]
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_131]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_131]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_131]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_131]
at io.druid.indexing.common.task.HadoopTask.invokeForeignLoader(HadoopTask.java:201) ~[druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
... 7 more
Caused by: java.lang.RuntimeException: java.lang.RuntimeException: No buckets?? seems there is no data to index.
at io.druid.indexer.IndexGeneratorJob.run(IndexGeneratorJob.java:215) ~[druid-indexing-hadoop-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexer.JobHelper.runJobs(JobHelper.java:349) ~[druid-indexing-hadoop-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexer.HadoopDruidIndexerJob.run(HadoopDruidIndexerJob.java:94) ~[druid-indexing-hadoop-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexing.common.task.HadoopIndexTask$HadoopIndexGeneratorInnerProcessing.runTask(HadoopIndexTask.java:261) ~[druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_131]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_131]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_131]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_131]
at io.druid.indexing.common.task.HadoopTask.invokeForeignLoader(HadoopTask.java:201) ~[druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
... 7 more
Caused by: java.lang.RuntimeException: No buckets?? seems there is no data to index.
at io.druid.indexer.IndexGeneratorJob.run(IndexGeneratorJob.java:176) ~[druid-indexing-hadoop-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexer.JobHelper.runJobs(JobHelper.java:349) ~[druid-indexing-hadoop-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexer.HadoopDruidIndexerJob.run(HadoopDruidIndexerJob.java:94) ~[druid-indexing-hadoop-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at io.druid.indexing.common.task.HadoopIndexTask$HadoopIndexGeneratorInnerProcessing.runTask(HadoopIndexTask.java:261) ~[druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_131]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[?:1.8.0_131]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_131]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_131]
at io.druid.indexing.common.task.HadoopTask.invokeForeignLoader(HadoopTask.java:201) ~[druid-indexing-service-0.9.2.2.6.0.3-8.jar:0.9.2.2.6.0.3-8]
... 7 more

从中，我们可以看到异常关键词：

No buckets?? seems there is no data to index.

一般情况下，我解决问题的思路是，先百度，后 github，再解决不了只能看源码。

因为druid这东西在国内并不火，所以百度没啥效果，然后到druid的github中，搜上述关键词，得到一条类似的issue：

https://github.com/druid-io/druid/issues/3259

这个issue虽然没能解决问题，但给我提供了解决问题的思路：修改timezone！

于是乎先看了系统的timezone，已经是CST，时间正常。

然后观察druid日志，发现druid日志与系统时间相差了8小时。

于是在ambari中，查找和timezone相关的druid配置，结果发现，有如下属性和timezone有关：

- druid.broker.jvm.opts

- druid.coordinator.jvm.opts

- druid.historical.jvm.opts

- druid.middlemanager.jvm.opts

- druid.overlord.jvm.opts

-druid.router.jvm.opts

-druid.indexer.runner.javaOpts

druid默认使用UTC，我这里发现日志和系统时间相差8小时，于是改为 UTC+8, 成功构建！