在36个机器上面跑一个大作业,8千多个map,2w多个reduce,跑reduce的时候经常会出现如下问题:
Map output lost, rescheduling: getMapOutput(attempt_201204130934_0012_m_000022_0,5416) failed :
java.io.IOException: Error Reading IndexFile
at org.apache.hadoop.mapred.IndexCache.readIndexFileToCache(IndexCache.java:113)
at org.apache.hadoop.mapred.IndexCache.getIndexInformation(IndexCache.java:66)
at org.apache.hadoop.mapred.TaskTracker$MapOutputServlet.doGet(TaskTracker.java:3651)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1221)
at org.apache.hadoop.http.HttpServer$QuotingInputFilter.doFilter(HttpServer.java:824)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:399)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:450)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:230)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:928)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
Caused by: java.io.EOFException
at java.io.DataInputStream.readFully(DataInputStream.java:180)
at java.io.DataInputStream.readLong(DataInputStream.java:399)
at org.apache.hadoop.mapred.SpillRecord.<init>(SpillRecord.java:75)
at org.apache.hadoop.mapred.SpillRecord.<init>(SpillRecord.java:55)
at org.apache.hadoop.mapred.IndexCache.readIndexFileToCache(IndexCache.java:109)
... 23 more
reduce读取不到map的输出结果,然后map重新跑,reduce重新读取数据,整个job运行时间就变长了。。
在官方issue MAPREDUCE-2389 Spurious EOFExceptions reading SpillRecord index files中有介绍。
解决方案:
(1)升级到成3u3(没有测试,但是应该能解决)
(2)把3u0的lib目录下面jetty相关包替换成3u3使用的就行(经过测试没有问题)
jetty-6.1.26.cloudera.1.jar 、jetty-servlet-tester-6.1.26.cloudera.1.jar 、jetty-util-6.1.26.cloudera.1.jar
(3)官方issue中有提到换成jetty-6.1.14(没有测试)