Hi, Thanks for the quick response. Wish the documentation was a bit more clear on it.
Now it works. I get "Live Datanodes : 1" in the NameNode console. >> modify fs.default.name from hdfs:/localhost:9050 to hdfs://master:9050 Just curious, how does it impact the Socket on the NameNode? Praveen On Fri, Apr 2, 2010 at 7:49 AM, zhu weimin <xim-...@tsm.kddilabs.jp> wrote: > Hi > > > > >Why is that the DataNode not able to Connect at port 9050 on the NameNode, > while the SocketClient.java connects to ?>SocketServer.java on port 9050? Is > there anything different that the NameNode creates a socket? > > > > modify fs.default.name from hdfs:/localhost:9050 to hdfs://master:9050 > > and modify mapred.job.tracker from localhost:9001 to master:9001 > > > > > > zhuweimin > > > > > > *From:* Praveen Sripati [mailto:praveensrip...@gmail.com] > *Sent:* Friday, April 02, 2010 11:00 AM > *To:* hdfs-user@hadoop.apache.org > *Subject:* DataNode not able to talk to NameNode > > > > Hi, > > I am trying to setup Hadoop on a two node cluster, both using Ubuntu 9.10. > I have configured one node as NameNode/JobTracker and the other as > DataNode/TaskTracker. > > I have the following in the hosts file for the master and the slave > > master> cat /etc/hosts > 192.168.0.100 master > 192.168.0.102 slave > 127.0.0.1 localhost > > slave> cat /etc/hosts > 192.168.0.100 master > 192.168.0.102 slave > 127.0.0.1 localhosts > > and the configuration file on the master and the slave has > > master -> core-site.xml -> fs.default.name->hdfs://localhost:9050 > -> hdfs-site.xml -> dfs.replication->1 > -> mapred-site.xml -> mapred.job.tracker->localhost:9001 > > slave -> core-site.xml -> fs.default.name->hdfs://master:9050 > -> hdfs-site.xml -> dfs.replication->1 > -> mapred-site.xml -> mapred.job.tracker->master:9001 > > > When I run the command start-dfs.sh, the NameNode starts without any errors > and the script tries to start the DataNode. But, the DataNode is not able to > connect to the MasterNode. The following is in the > hadoop-praveensripati-datanode-slave.log file > > 2010-04-02 06:54:35,630 INFO org.apache.hadoop.ipc.Client: Retrying connect > to server: master/192.168.0.100:9050. Already tried 9 time(s). > 2010-04-02 06:54:35,645 INFO org.apache.hadoop.ipc.RPC: Server at master/ > 192.168.0.100:9050 not available yet, Zzzzz... > > 1. Able to ping the master from the slave and the other way. > 2. Able to ssh into slave from master and other way. > 3. Disabled ipv6 on master and slave. /etc/sysctl.conf has > net.ipv6.conf.all.disable_ipv6 = 1. > > I wrote a Java SocketClient Program to connect from the DataNode to the > NameNode at port 9050 and I get the following exception > > java.net.ConnectException: Connection refused > at java.net.PlainSocketImpl.socketConnect(Native Method) > at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333) > at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195) > at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182) > at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366) > at java.net.Socket.connect(Socket.java:525) > at SocketClient.main(SocketClient.java:23) > > Then, I stop the NameNode and DataNode and then by using Java Programs I > create a socket (at 9050) on the NameNode and am able to connect from the > DataNode using Java Program. > > ServerSocket.java has > > int port = Integer.parseInt(args[0]); > ServerSocket srv = new ServerSocket(port); > Socket socket = srv.accept(); > > SocketClient.java has > > InetAddress addr = InetAddress.getByName(args[0]); > int port = Integer.parseInt(args[1]); > SocketAddress sockaddr = new InetSocketAddress(addr, port); > Socket sock = new Socket(); > int timeoutMs = 2000; > sock.connect(sockaddr, timeoutMs); > > When I do 'netstat -a | grep 9050' I get > > When NameNode creates the Socket -> tcp 0 0 > localhost:9050 *:* LISTEN > When Java Program creates a Socket -> tcp 0 0 > *:9050 *:* LISTEN > > Why is that the DataNode not able to Connect at port 9050 on the NameNode, > while the SocketClient.java connects to SocketServer.java on port 9050? Is > there anything different that the NameNode creates a socket? > -- > Praveen > -- Praveen
