hi.
i have a small hadoop grid connected with a 1g network.
when servers are configured to use the local dns server the jobs are
running without a problem and copy speed during reduce is tens on MB.
once i change the servers to work with a cache only named server on each
node, i start to get failed tasks with timeout errors.
also, copy speed is reduced to under 1M.
there is NO degradation in network, copy of files between servers is
still tens of MB.
resolving is working ok and in the same speed (give or take) with both
configurations.
any idea of what happens during the map/reduce process that causes this
behavior?
this is an example for the exceptions i get during map:
Too many fetch-failures
and during reduce:
java.lang.RuntimeException:
org.apache.hadoop.hbase.ZooKeeperConnectionException:
java.net.UnknownHostException: s06.xxx.local at
org.apache.hadoop.hbase.client.HTableFactory.createHTableInterface(HTableFactory.java:38)
at
org.apache.hadoop.hbase.client.HTablePool.createHTable(HTablePool.java:129)
at
org.apache.hadoop.hbase.client.HTablePool.getTable(HTablePool.java:89)
at
com.infolinks.hadoop.commons.hbase.HBaseOperations.getTable(HBaseOperations.java:118)
at
com.infolinks.hadoop.framework.HBaseReducer.setup(HBaseReducer.java:71)
at org.apache.hadoop.mapreduce.Reducer.run(Reducer.java:174) at
org.apache.hadoop.mapred.ReduceTask.runNewReducer(ReduceTask.java:566)
at org.apache.hadoop.mapred.ReduceTask.run(ReduceTask.java:408) at
org.apache.hadoop.mapred.Child.main(Child.java:170) Caused by:
org.apache.hadoop.hbase.ZooKeeperConnectionException:
java.net.UnknownHostException: s06.xxx.local at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getZooKeeperWatcher(HConnectionManager.java:1000)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.setupZookeeperTrackers(HConnectionManager.java:303)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.(HConnectionManager.java:294)
at
org.apache.hadoop.hbase.client.HConnectionManager.getConnection(HConnectionManager.java:156)
at org.apache.hadoop.hbase.client.HTable.(HTable.java:167) at
org.apache.hadoop.hbase.client.HTableFactory.createHTableInterface(HTableFactory.java:36)
... 8 more Caused by: java.net.UnknownHostException: s06.xxx.local at
java.net.InetAddress.getAllByName0(InetAddress.java:1158) at
java.net.InetAddress.getAllByName(InetAddress.java:1084) at
java.net.InetAddress.getAllByName(InetAddress.java:1020) at
org.apache.zookeeper.ClientCnxn.(ClientCnxn.java:386) at
org.apache.zookeeper.ClientCnxn.(ClientCnxn.java:331) at
org.apache.zookeeper.ZooKeeper.(ZooKeeper.java:377) at
org.apache.hadoop.hbase.zookeeper.ZKUtil.connect(ZKUtil.java:97) at
org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher.(ZooKeeperWatcher.java:119)
at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getZooKeeperWatcher(HConnectionManager.java:998)
... 13 more
thank you,
Oren.
