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Join For FreeIf you are trying to run the word_count example in Cassandra Hadoop, and you encounter the following exception:
java.lang.RuntimeException: java.lang.UnsupportedOperationException: no local connection available
at org.apache.cassandra.hadoop.ColumnFamilyRecordReader.initialize(ColumnFamilyRecordReader.java:132)
at org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.initialize(MapTask.java:418)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:620)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:177)
Caused by: java.lang.UnsupportedOperationException: no local connection available
at org.apache.cassandra.hadoop.ColumnFamilyRecordReader.getLocation(ColumnFamilyRecordReader.java:176)
at org.apache.cassandra.hadoop.ColumnFamilyRecordReader.initialize(ColumnFamilyRecordReader.java:113)
... 4 more
Then you have hit a problem with local IP resolution in Java.
I submitted a patch for this. If you are having issues, please vote to get the patch accepted.
https://issues.apache.org/jira/browse/CASSANDRA-3211
java.lang.RuntimeException: java.lang.UnsupportedOperationException: no local connection available
at org.apache.cassandra.hadoop.ColumnFamilyRecordReader.initialize(ColumnFamilyRecordReader.java:132)
at org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.initialize(MapTask.java:418)
at org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:620)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:305)
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:177)
Caused by: java.lang.UnsupportedOperationException: no local connection available
at org.apache.cassandra.hadoop.ColumnFamilyRecordReader.getLocation(ColumnFamilyRecordReader.java:176)
at org.apache.cassandra.hadoop.ColumnFamilyRecordReader.initialize(ColumnFamilyRecordReader.java:113)
... 4 more
Then you have hit a problem with local IP resolution in Java.
Cassandra currently uses the following line to resolve IP addresses;
localAddresses = InetAddress.getAllByName(InetAddress.getLocalHost().getHostAddress());
There are better ways to do this using the NetworkInterface,
But
until Cassandra uses that you'll need to make sure that the bit of code
above resolves properly by manipulating your /etc/hosts to resolve
localhost to match the configuration in Cassandra, which by default is
looking for localhost bound to 127.0.0.1.
I submitted a patch for this. If you are having issues, please vote to get the patch accepted.
https://issues.apache.org/jira/browse/CASSANDRA-3211
Connection (dance)
hadoop
Published at DZone with permission of Brian O' Neill, DZone MVB. See the original article here.
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