HTTP ERROR 500
Problem accessing /nn_browsedfscontent.jsp. Reason:
Cannot issue delegation token. Name node is in safe mode.
The reported blocks 0 needs additional 10 blocks to reach the threshold 0.9990 of total blocks 10.
Safe mode will be turned off automatically
Caused by:
org.apache.hadoop.hdfs.server.namenode.SafeModeException: Cannot issue delegation token. Name node is in safe mode.
The reported blocks 0 needs additional 10 blocks to reach the threshold 0.9990 of total blocks 10.
Safe mode will be turned off automatically
at org.apache.hadoop.hdfs.server.namenode.FSNamesystem.getDelegationToken(FSNamesystem.java:5887)
at org.apache.hadoop.hdfs.server.namenode.NameNodeRpcServer.getDelegationToken(NameNodeRpcServer.java:447)
at org.apache.hadoop.hdfs.server.namenode.NamenodeJspHelper$1.run(NamenodeJspHelper.java:623)
at org.apache.hadoop.hdfs.server.namenode.NamenodeJspHelper$1.run(NamenodeJspHelper.java:620)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1491)
at org.apache.hadoop.hdfs.server.namenode.NamenodeJspHelper.getDelegationToken(NamenodeJspHelper.java:619)
at org.apache.hadoop.hdfs.server.namenode.NamenodeJspHelper.redirectToRandomDataNode(NamenodeJspHelper.java:651)
at org.apache.hadoop.hdfs.server.namenode.nn_005fbrowsedfscontent_jsp._jspService(nn_005fbrowsedfscontent_jsp.java:70)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:9
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1221)
at org.apache.hadoop.http.lib.StaticUserWebFilter$StaticUserFilter.doFilter(StaticUserWebFilter.java:109)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
at org.apache.hadoop.http.HttpServer$QuotingInputFilter.doFilter(HttpServer.java:1081)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
at org.apache.hadoop.http.NoCacheFilter.doFilter(NoCacheFilter.java:45)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1212)
at org.apache.hadoop.http.NoCacheFilter.doFilter(NoCacheFilter.java:45)
at org.mortbay.jetty.servlet.ServletHandler$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$RequestHandler.headerComplete(HttpConnection.java:92
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:549)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:212)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
解决办法：
重启30秒内，nn处于安全模式，执行命令hadoop dfsadmin -safemode leave