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From Fei Dong <dongfei...@gmail.com>
Subject Re: NoClassDefFoundError when running Hadoop with HBase
Date Tue, 24 Jan 2012 16:11:08 GMT
Thanks Stack,

On Tue, Jan 24, 2012 at 1:07 AM, Stack <stack@duboce.net> wrote:
> On Mon, Jan 23, 2012 at 5:32 PM, Fei Dong <dongfeiwww@gmail.com> wrote:
>> Hello guys,
>>
>> I setup a Hadoop and HBase in EC2. My Settings as follows:
>> Apache Official Version
>> Hadoop 0.20.203.0
>
> HBase won't work on this version of hadoop.  See
> http://hbase.apache.org/book.html#hadoop
>
It says only Hadoop 0.20.205.x can match?

>
>> export HADOOP_CLASSPATH="$HADOOP_CLASSPATH:$HBASE_HOME/lib/zookeeper.jar"
>> export HADOOP_CLASSPATH="$HADOOP_CLASSPATH:$HBASE_HOME/hbase.jar"
>>
>
> The jars are not normally named as you have them above.  Usually there
> is a version on the jar name.
>
I soft-linked the zookeeper.jar and hbase to the version ones.

>
>> 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.
>>        at org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.<init>(ZooKeeperWatcher.java:155)
>>        at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getZooKeeperWatcher(HConnectionManager.java:1002)
>>        at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.setupZookeeperTrackers(HConnectionManager.java:304)
>>        at org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.<init>(HConnectionManager.java:295)
>>        at org.apache.hadoop.hbase.client.HConnectionManager.getConnection(HConnectionManager.java:157)
>> """
>>
>
> Search this mailing list archive for similar reports to above.    Up
> your maximum count of concurrent zookeeper connections as work around.
>
I did not run any application before, so it should not have concurrent
problem. Then I set it in hbase-site.xml, it still reports such error.
    <name>hbase.zookeeper.property.maxClientCnxns</name>
    <value>1000</value>

>
>> 2)
>> When another mapreduce job:
>>
>> /usr/local/hadoop-0.20.203.0/bin/hadoop jar
>> ./bin/../dist/xxxxxx.jar pMapReduce.SmartRunner -numReducers
>> 80 -inDir /root/test1/input -outDir /root/test1/output -landmarkTable
>> Landmarks -resultsTable test_one -numIter 10 -maxLatency 75
>> -filterMinDist 10 -hostAnswerWeight 5 -minNumLandmarks 1 -minNumMeas 1
>> -alwaysUseWeightedIxn -writeFullDetails -weightMonte -allTarg
>> -allLookup -clean -cleanResultsTable
>>
>> JobTracker shows error:
>> ""
>> 12/01/23 00:51:31 INFO mapred.JobClient: Running job: job_201201212243_0009
>> 12/01/23 00:51:32 INFO mapred.JobClient:  map 0% reduce 0%
>> 12/01/23 00:51:40 INFO mapred.JobClient: Task Id :
>> attempt_201201212243_0009_m_000174_0, Status : FAILED
>> java.lang.Throwable: Child Error
>>        at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:271)
>> Caused by: java.io.IOException: Task process exit with nonzero status of 1.
>>        at org.apache.hadoop.mapred.TaskRunner.run(TaskRunner.java:258)
>> """
>>
>> TaskTracker log:
>> """
>> Could not find the main class: .  Program will exit.
>> Exception in thread "main" java.lang.NoClassDefFoundError:
>> Caused by: java.lang.ClassNotFoundException:
>>        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
>>        at java.security.AccessController.doPrivileged(Native Method)
>>        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
>>        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
>>        at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
>>        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
>> Could not find the main class: .  Program will exit.
>> """
>
> Thats a pretty basic failure; it couldn't find basic class java class
> in classpath.  Can you dig in more on this?  You've seen this:
> http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/mapreduce/package-summary.html#classpath
>
I will first install Hadoop0.20.205 and try again.

> St.Ack
>
>>
>> The real entry is the main() in SmartRunner.class
>>  jar tf ./bin/../dist/xxxxxx.jar|grep SmartRunner
>> pMapReduce/SmartRunner.class
>>
>> Can anyone help me, thanks a lot.
>> --
>> Best Regards,
>> --
>> Fei Dong



-- 
Best Regards,
--
Fei Dong

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