运行水槽下载twitter数据时出现未处理java.lang.错误

Question

当我运行这个命令时

hduser@ubuntu:/usr/local/flume$ bin/flume-ng agent --conf ./conf/ -f conf/twitterflume-agent.conf -Dflume.root.logger=DEBUG,console -n TwitterAgent

水槽正在启动，但过了一段时间，它向我抛出了不允许水槽下载的异常。我收到以下错误：

2015-10-31 10:18:32,152 (conf-file-poller-0) [INFO - org.apache.flume.sink.DefaultSinkFactory.create(DefaultSinkFactory.java:40)] Creating instance of sink: HDFS, type: hdfs

2015-10-31 10:18:35,386 (conf-file-poller-0) [ERROR - org.apache.flume.node.PollingPropertiesFileConfigurationProvider$FileWatcherRunnable.run(PollingPropertiesFileConfigurationProvider.java:149)] Unhandled error
java.lang.NoSuchMethodError: com.google.common.cache.CacheBuilder.refreshAfterWrite(JLjava/util/concurrent/TimeUnit;)Lcom/google/common/cache/CacheBuilder;
    at org.apache.hadoop.security.Groups.<init>(Groups.java:97)
    at org.apache.hadoop.security.Groups.<init>(Groups.java:74)
    at org.apache.hadoop.security.Groups.getUserToGroupsMappingService(Groups.java:303)
    at org.apache.hadoop.security.UserGroupInformation.initialize(UserGroupInformation.java:283)
    at org.apache.hadoop.security.UserGroupInformation.ensureInitialized(UserGroupInformation.java:260)
    at org.apache.hadoop.security.UserGroupInformation.isAuthenticationMethodEnabled(UserGroupInformation.java:337)
    at org.apache.hadoop.security.UserGroupInformation.isSecurityEnabled(UserGroupInformation.java:331)
    at org.apache.flume.sink.hdfs.HDFSEventSink.authenticate(HDFSEventSink.java:491)
    at org.apache.flume.sink.hdfs.HDFSEventSink.configure(HDFSEventSink.java:240)
    at org.apache.flume.conf.Configurables.configure(Configurables.java:41)
    at org.apache.flume.node.AbstractConfigurationProvider.loadSinks(AbstractConfigurationProvider.java:418)
    at org.apache.flume.node.AbstractConfigurationProvider.getConfiguration(AbstractConfigurationProvider.java:103)
    at org.apache.flume.node.PollingPropertiesFileConfigurationProvider$FileWatcherRunnable.run(PollingPropertiesFileConfigurationProvider.java:140)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:304)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:178)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)

出现此错误后，它尝试进行检查，但未能下载数据。

2015-10-31 10:28:05,446 (conf-file-poller-0) [DEBUG - org.apache.flume.node.PollingPropertiesFileConfigurationProvider$FileWatcherRunnable.run(PollingPropertiesFileConfigurationProvider.java:126)] Checking file:conf/twitterflume-agent.conf for changes
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我是Hadoop和Flume的新手。

Answer 1

似乎是编译和运行时库不兼容。编译代码和运行代码时出现的库是不同的。

检查在运行水槽代码时是否提供了正确的类路径。在运行代理程序的节点上，运行 ps aux|grep flume 以检查类路径。

还要注意，如果你修改了Twitter代码，增加了库，就会导致这个问题，因为Flume也有自己的Twitter源代码。在这种情况下，要么删除Twitter jar，要么从类路径中删除Flume的Twitter jar。