Connection refused when connecting to hbase from mapper task

[leiwang...@gmail.com]

In the following code,  I just want to connect to hbase and do a get operation 
in a mapper.
Any insight on this?

Thanks,
Lei

public class TagMapper extends Mapper<LongWritable, Text, Text, Text> { 

private HTable hTable; 

@Override 
protected void setup(Context context){ 
try { 
    hTable = new HTable(context.getConfiguration(), "userdigest"); 
} catch (IOException e) { 
    e.printStackTrace(); 
} 
} 

@Override 
public void map(LongWritable key, Text value, Context context) 
throws IOException, InterruptedException { 

String agid = value.toString(); 
Get get = new Get(Bytes.toBytes(agid)); 
Result rs = hTable.get(get); 
for(KeyValue kv:rs.raw()){ 

context.write(new Text(new String(kv.getRow())+":" + new 
String(kv.getQualifier())), new Text(new String(kv.getValue()))); 

} 
} 
}

The task error log: 
java.net.ConnectException: Connection refused
        at sun.nio.ch.SocketChannelImpl.checkConnect(Native Method)
        at 
sun.nio.ch.SocketChannelImpl.finishConnect(SocketChannelImpl.java:599)
        at 
org.apache.zookeeper.ClientCnxnSocketNIO.doTransport(ClientCnxnSocketNIO.java:350)
        at org.apache.zookeeper.ClientCnxn$SendThread.run(ClientCnxn.java:1068)
2014-08-15 17:43:11,102 WARN 
org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper: Possibly transient 
ZooKeeper exception: 
org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = 
ConnectionLoss for /hbase/hbaseid
2014-08-15 17:43:11,103 INFO org.apache.zookeeper.ClientCnxn: Opening socket 
connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate 
using SASL (Unable to locate a login configuration)
2014-08-15 17:43:11,103 ERROR 
org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper: ZooKeeper exists failed 
after 3 retries
2014-08-15 17:43:11,103 WARN org.apache.hadoop.hbase.zookeeper.ZKUtil: 
hconnection Unable to set watcher on znode (/hbase/hbaseid)
org.apache.zookeeper.KeeperException$ConnectionLossException: KeeperErrorCode = 
ConnectionLoss for /hbase/hbaseid
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:99)
        at org.apache.zookeeper.KeeperException.create(KeeperException.java:51)
        at org.apache.zookeeper.ZooKeeper.exists(ZooKeeper.java:1041)
        at 
org.apache.hadoop.hbase.zookeeper.RecoverableZooKeeper.exists(RecoverableZooKeeper.java:172)
        at org.apache.hadoop.hbase.zookeeper.ZKUtil.checkExists(ZKUtil.java:450)
        at 
org.apache.hadoop.hbase.zookeeper.ClusterId.readClusterIdZNode(ClusterId.java:61)
        at org.apache.hadoop.hbase.zookeeper.ClusterId.getId(ClusterId.java:50)
        at org.apache.hadoop.hbase.zookeeper.ClusterId.hasId(ClusterId.java:44)
        at 
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.ensureZookeeperTrackers(HConnectionManager.java:615)
        at 
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:871)
        at 
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:846)
        at org.apache.hadoop.hbase.client.HTable.finishSetup(HTable.java:271)
        at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:211)
        at org.apache.hadoop.hbase.client.HTable.<init>(HTable.java:170)
        at 
com.agrantsem.data.mapreduce.userdigest.TagMapper.setup(TagMapper.java:23)
        at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:138)
        at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:672)
        at org.apache.hadoop.mapred.MapTask.run(MapTask.java:330)
        at org.apache.hadoop.mapred.Child$4.run(Child.java:268)
        at java.security.AccessController.doPrivileged(Native Method)
        at javax.security.auth.Subject.doAs(Subject.java:396)
        at 
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1408)
        at org.apache.hadoop.mapred.Child.main(Child.java:262)
2014-08-15 17:43:11,103 WARN org.apache.zookeeper.ClientCnxn: Session 0x0 for 
server null, unexpected error, closing socket connection and attempting 
reconnect


leiwang...@gmail.com