2012-12-31 15:49:11,853 ERROR org.apache.hadoop.hdfs.server.datanode.DataNode: java.net.UnknownHostException: locahost: locahost at java.net.InetAddress.getLocalHost(InetAddress.java:1374) at org.apache.hadoop.security.SecurityUtil.getLocalHostName(SecurityUtil.java:252) at org.apache.hadoop.security.SecurityUtil.login(SecurityUtil.java:270) at org.apache.hadoop.hdfs.server.datanode.DataNode.<init>(DataNode.java:291) at org.apache.hadoop.hdfs.server.datanode.DataNode.makeInstance(DataNode.java:1582) at org.apache.hadoop.hdfs.server.datanode.DataNode.instantiateDataNode(DataNode.java:1521) at org.apache.hadoop.hdfs.server.datanode.DataNode.createDataNode(DataNode.java:1539) at org.apache.hadoop.hdfs.server.datanode.DataNode.secureMain(DataNode.java:1665) at org.apache.hadoop.hdfs.server.datanode.DataNode.main(DataNode.java:1682)