namenode « hadoop « Java Database Q&A

1. Error in starting namenode in Hadoop    stackoverflow.com

When I try to format the namenode or even start it I'm getting the below error. What should be done??

$ bin/hadoop namenode -format

Exception in thread "main" java.lang.NoClassDefFoundError:
Caused by: java.lang.ClassNotFoundException:
   ...

2. hadoop on vmware, namenode not finding slaves    stackoverflow.com

I set up 3 identical linux (CentOS) servers on Vmware. Basically built one and made 2 fully clones. I edit each servers hostnames : server1, server2,server3 and added them to each ...

3. Hadoop Installation: no jobtracker to stop no namenode to stop    stackoverflow.com

Hadoop-0.20.2 Single Node Setup FAIL!!!! The jobtracker and namenode do not start :( Any suggestions would be welcome. As far as i know, i have set core-site.xml, hdfs-site.xml and mapred-site.xml correctly ...

4. hadoop namenode single point of failure    stackoverflow.com

The namenode in the hadoop architecture is a single point of failure. How do people who have large hadoop clusters cope with this problem. Is there an industry-accepted solution that has ...

5. How to password protect Hadoop NameNode and JobTracker Web UIs?    stackoverflow.com

I'd like to know how to password protect the Hadoop Web UIs running on ports 50030, 50070, etc.

6. after replace mapred/hdfs/common jar build via Hadoop from SVN "no namenode to stop"    stackoverflow.com

I checkout the source code from http://svn.apache.org/repos/asf/hadoop/common http://svn.apache.org/repos/asf/hadoop/hdfs http://svn.apache.org/repos/asf/hadoop/mapreduce and get hadoop-mapred-0.23.0-SNAPSHOT.jar hadoop-hdfs -0.23.0-SNAPSHOT.jar hadoop-common-0.23.0-SNAPSHOT.jar but I failed to start-all.sh with these jars... Jobtracker and tasktracker started for just 5 secs and automatically ...

7. How can I tell if a hadoop namenode has already been formatted?    stackoverflow.com

When configuring my hadoop namenode for the first time, I know I need to run

bin/hadoop namenode -format

8. Hadoop Mapreduce with two jars (one of the jars is needed on namenode only)    stackoverflow.com

The mapred task is a very simple 'wordcount' implemented by Java (plz, see http://wiki.apache.org/hadoop/WordCount ). after the last line, "job.waitForCompletion(true);" I add some code implemented by Jython. It means the libraries for ...

9. Hadoop namenode metadata    stackoverflow.com

I am a bit confused by the Hadoop architecture.

1. What kind of file metadata is stored in Hadoop Namenode? From Hadoop wiki, it says Namenode stores the entire system namespace. Does ...

10. "hadoop namenode -format" returns a java.net.UnknownHostException    stackoverflow.com

I'm currently learning hadoop and I'm trying to setup a single node test as defined in http://hadoop.apache.org/common/docs/current/single_node_setup.html I've configured ssh (I can log without a password). My server is on our ...

11. no namenode error in pseudo-mode    stackoverflow.com

I'm new to hadoop and is in learning phase. As per Hadoop Definitve guide, i have set up my hadoop in pseudo distributed mode and everything was working fine. I was even ...

12. Hadoop NameNode failed to start, Error: FSNamesystem initialization failed. java.io.FileNotFoundException    stackoverflow.com

Exception I am getting is,

2011-07-13 12:04:13,006 ERROR org.apache.hadoop.hdfs.server.namenode.NameNode: java.io.FileNotFoundException: File does not exist: /opt/data/tmp/mapred/system/job_201107041958_0120/j^@^@^@^@^@^@
        at org.apache.hadoop.hdfs.server.namenode.FSDirectory.unprotectedSetPermission(FSDirectory.java:544)
        at ...

13. Hadoop Datanode, namenode, secondary-namenode, job-tracker and task-tracker    stackoverflow.com

I am new in hadoop so I have some doubts. If the master-node fails what happened the hadoop cluster? Can we recover that node without any lose? Is it possible to ...

14. Server returns 403 during secondary namenode docheckpoint with namenode    stackoverflow.com

I am configuring hadoop on clusters. All node started successfully, but secondary node failed doCheckpoint with following log:

2011-10-25 11:09:07,207 ERROR org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: Exception in doCheckpoint: 
2011-10-25 11:09:07,208 ERROR org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode: java.io.IOException: Server returned HTTP ...

15. What is the meaning of EOF exceptions in hadoop namenode connections from hbase/filesystem?    stackoverflow.com

This is both a general question about java EOF exceptions, as well as Hadoop's EOF exception which is related to jar interoperability. Comments and answers on either topic are acceptable. ...

16. Namenode not getting started    stackoverflow.com

I was using Hadoop in a pseudo-distributed mode and everything was working fine.But then I had to restart my computer because of some reason.And now when I am trying to start ...