Thanks for your suggestion J-D, I hadn't tried that.
So, following your advice, below is the error log from one of the slaves in
my cluster. Maybe those "connection refused" messages are the cause of the
exception... Does it ring any bells for you?
2011-11-16 14:37:14,641 INFO org.apache.zookeeper.ZooKeeper: Client
environment:user.home=/home/hadoop1
2011-11-16 14:37:14,641 INFO org.apache.zookeeper.ZooKeeper: Client
environment:user.dir=/mapred/taskTracker/jobcache/job_201111161435_0001/atte
mpt_201111161435_0001_m_000000_0/work
2011-11-16 14:37:14,641 INFO org.apache.zookeeper.ZooKeeper: Initiating
client connection, connectString=localhost:2181 sessionTimeout=180000
watcher=hconnection
2011-11-16 14:37:14,670 INFO org.apache.zookeeper.ClientCnxn: Opening socket
connection to server localhost/127.0.0.1:2181
2011-11-16 14:37:14,671 WARN org.apache.zookeeper.ClientCnxn: Session 0x0
for server null, unexpected error, closing socket connection and attempting
reconnect
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at
sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at
org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1119)
2011-11-16 14:37:15,412 INFO org.apache.zookeeper.ClientCnxn: Opening socket
connection to server localhost/127.0.0.1:2181
2011-11-16 14:37:15,412 WARN org.apache.zookeeper.ClientCnxn: Session 0x0
for server null, unexpected error, closing socket connection and attempting
reconnect
...
(omitting 8 identical retries and fails)
...
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at
sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at
org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1119)
2011-11-16 14:37:26,172 INFO org.apache.zookeeper.ClientCnxn: Opening socket
connection to server localhost/127.0.0.1:2181
2011-11-16 14:37:26,173 WARN org.apache.zookeeper.ClientCnxn: Session 0x0
for server null, unexpected error, closing socket connection and attempting
reconnect
java.net.ConnectException: Connection refused
at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
at
sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:567)
at
org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1119)
2011-11-16 14:37:26,373 INFO org.apache.zookeeper.ZooKeeper: Session: 0x0
closed
2011-11-16 14:37:26,373 ERROR
org.apache.hadoop.hbase.mapreduce.TableOutputFormat:
org.apache.hadoop.hbase.ZooKeeperConnectionException: HBase is able to
connect to ZooKeeper but the connection closes immediately. This could be a
sign that the server has too many connections (30 is the default). Consider
inspecting your ZK server logs for that error and then make sure you are
reusing HBaseConfiguration as often as you can. See HTable's javadoc for
more information.
2011-11-16 14:37:26,375 INFO org.apache.zookeeper.ClientCnxn: EventThread
shut down
2011-11-16 14:37:26,423 WARN org.apache.hadoop.mapred.TaskTracker: Error
running child
java.lang.NullPointerException
at
org.apache.hadoop.hbase.mapreduce.TableOutputFormat$TableRecordWriter.write(
TableOutputFormat.java:127)
at
org.apache.hadoop.hbase.mapreduce.TableOutputFormat$TableRecordWriter.write(
TableOutputFormat.java:82)
at
org.apache.hadoop.mapred.MapTask$NewDirectOutputCollector.write(MapTask.java
:498)
at
org.apache.hadoop.mapreduce.TaskInputOutputContext.write(TaskInputOutputCont
ext.java:80)
at SampleUploader$Uploader.map(SampleUploader.java:99)
at SampleUploader$Uploader.map(SampleUploader.java:1)
at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:144)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:621)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305)
at org.apache.hadoop.mapred.Child.main(Child.java:170)
2011-11-16 14:37:26,425 INFO org.apache.hadoop.mapred.TaskRunner: Runnning
cleanup for the task
-----Original Message-----
From: jdcry...@gmail.com [mailto:jdcry...@gmail.com] On Behalf Of
Jean-Daniel Cryans
Sent: 15 November 2011 21:30
To: user@hbase.apache.org
Subject: Re: n00b trying to run HBase example code
If I remember correctly, this NPE doesn't come alone but you have to go into
that tasks' log to find the rest as the job output you have only shows what
ended up killing the task. Go to the jobtracker's web ui, click on your job,
click on the number of failed tasks, look at the log of one of those tasks,
and look for anything that looks bad at the end of the log before the NPE.
Hope this helps,
J-D
On Mon, Nov 14, 2011 at 3:30 PM, Royston Sellman
<royston.sell...@cse.org.uk> wrote:
> Apologies if this is the wrong forum, or has come up before, or is
RTFM-class...
>
> I'm trying to run HBase example code. I think I have HBase running OK on
my 6 node cluster: I can create tables with the HBase shell. I can create
tables with the ExampleClient from Chapter 13 of the Hadoop book. I can
load the HBase Master: namenode:60000 web page and see tables I've created.
But when I try to run SampleUploader from the HBase examples I get the (not
very helpful to me) exception below. I get a similar error when trying to
run the HBseTemperatureImporter bulk load example from the Hadoop book also
i.e. mapred.JobClient failing 4 times before giving up.
>
> Thanks,
> Royston.
