Hi Sameer, Do you see all processes up? Can you check the logs and see what is going wrong? I suspect you will need to make the entries in /etc/hosts anyways. Somewhere in hadoop code, the ip hostname mapping is done, I forget the exact location.
Thanks and Regards, Sonal www.meghsoft.com http://in.linkedin.com/in/sonalgoyal On Wed, Jul 28, 2010 at 10:38 PM, Sameer Joshi < [email protected]> wrote: > Hi Sonal, > Thank you for replying. > > I'm trying to run it as single node, so I had localhost in all the conf > files and in /etc/hosts. I tried replacing it with 127.0.0.1 in all Hadoop > conf files (read to do that on some forum), but with no change. > > I figured I didn't need hostname since I was trying to run it locally, but > still tried replacing localhost with 173.1.86.194. However, as expected, it > could not connect to server. > > Any thoughts? > > Thanks for your help, I'm new at this and feel much obliged. > > Regards, > Sameer > > On Wed, Jul 28, 2010 at 12:12 AM, Sonal Goyal <[email protected]> > wrote: > > > Hi Sameer, > > > > For GoGrid, you will have to configure /etc/hosts with the ip and > hostname > > for master and slaves. If you run hostname and nslookup -sil, you will > get > > the details for your machines. Make sure /etc/hosts has an entry like: > > > > 173.1.45.202 173.1.45.202.reverse.gogrid.com 28684_1_85017_358406 > > > > Thanks and Regards, > > Sonal > > www.meghsoft.com > > http://in.linkedin.com/in/sonalgoyal > > > > > > On Wed, Jul 28, 2010 at 6:42 AM, Sameer Joshi < > > [email protected]> wrote: > > > > > I installed Java and Hadoop on a GoGrid cloud server using Red Hat > > > Enterprise Linux Server release 5.1 (Tikanga). Hadoop installed fine > and > > > starts fine, however I get an error (java.lang.NullPointerException at > > > java.util.concurrent.ConcurrentHashMap) while running the Hadoop > > wordcount > > > example. My guess was that this was a localhost or IPv6 issue. > > > > > > * I have tested replacing 'localhost' with both the local IP, and > server > > IP > > > addresses (when out of options) in Hadoop conf > > > * I have disabled IPv6 both in sysctl.conf and hadoop-env.sh (former > > > followed by a server restart) > > > > > > Any thoughts? > > > Thank you. > > > > > > > > > The output is given below > > > > > > # bin/hadoop jar hadoop-0.20.2-examples.jar wordcount datasets > tests/out7 > > > 10/07/27 05:44:59 INFO input.FileInputFormat: Total input paths to > > process > > > : > > > 1 > > > 10/07/27 05:44:59 INFO mapred.JobClient: Running job: > > job_201007270544_0001 > > > 10/07/27 05:45:00 INFO mapred.JobClient: map 0% reduce 0% > > > 10/07/27 05:45:12 INFO mapred.JobClient: map 100% reduce 0% > > > 10/07/27 05:45:17 INFO mapred.JobClient: Task Id : > > > attempt_201007270544_0001_r_000000_0, Status : FAILED > > > > > > Error: java.lang.NullPointerException > > > at java.util.concurrent.ConcurrentHashMap.get(Unknown Source) > > > at > > > > > > > > > org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2683) > > > > > > at > > > > > > > > > org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2605) > > > > > > > > > 10/07/27 05:45:24 INFO mapred.JobClient: Task Id : > > > attempt_201007270544_0001_r_000000_1, Status : FAILED > > > Error: java.lang.NullPointerException > > > at java.util.concurrent.ConcurrentHashMap.get(Unknown Source) > > > at > > > > > > > > > org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2683) > > > > > > at > > > > > > > > > org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2605) > > > > > > > > > 10/07/27 05:45:30 INFO mapred.JobClient: Task Id : > > > attempt_201007270544_0001_r_000000_2, Status : FAILED > > > Error: java.lang.NullPointerException > > > at java.util.concurrent.ConcurrentHashMap.get(Unknown Source) > > > at > > > > > > > > > org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.getMapCompletionEvents(ReduceTask.java:2683) > > > > > > at > > > > > > > > > org.apache.hadoop.mapred.ReduceTask$ReduceCopier$GetMapEventsThread.run(ReduceTask.java:2605) > > > > > > > > > 10/07/27 05:45:39 INFO mapred.JobClient: Job complete: > > > job_201007270544_0001 > > > > > > 10/07/27 05:45:39 INFO mapred.JobClient: Counters: 12 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Job Counters > > > 10/07/27 05:45:39 INFO mapred.JobClient: Launched reduce tasks=4 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Launched map tasks=1 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Data-local map tasks=1 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Failed reduce tasks=1 > > > 10/07/27 05:45:39 INFO mapred.JobClient: FileSystemCounters > > > 10/07/27 05:45:39 INFO mapred.JobClient: HDFS_BYTES_READ=15319 > > > 10/07/27 05:45:39 INFO mapred.JobClient: FILE_BYTES_WRITTEN=12847 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Map-Reduce Framework > > > 10/07/27 05:45:39 INFO mapred.JobClient: Combine output records=934 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Map input records=149 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Spilled Records=934 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Map output bytes=25346 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Combine input records=2541 > > > 10/07/27 05:45:39 INFO mapred.JobClient: Map output records=2541 > > > > > > -- > > > Dr. Sameer Joshi, Ph.D. > > > Senior computer scientist, > > > Serene Software. > > > > > > > > > -- > Dr. Sameer Joshi, Ph.D. > Senior computer scientist, > Serene Software. >
