毛宏 wrote:
I downloaded Hadoop 0.20.0 and used the src/contrib/ec2/bin scripts to
launch a Hadoop cluster on Amazon EC2, after building a new Hadoop
0.20.0 AMI.
I launched an instance with my new Hadoop 0.20.0 AMI, then logged in and
ran the following to launch a new cluster:
root(/vol/hadoop-0.20.0)> bin/launch-hadoop-cluster hadoop-test 2
After the usual EC2 wait, one master and two slave instances were
launched on EC2, as expected. When I ssh'ed into the instances, here is
what I found:
Slaves: DataNode and NameNode are running
Master: Only NameNode is running
I could use HDFS commands (using $HADOOP_HOME/bin/hadoop scripts)
without any problems, from both master and slaves. However, since
JobTracker is not running, I cannot run map-reduce jobs.
2009-09-03 18:55:48,628 INFO org.apache.hadoop.hdfs.DFSClient:
org.apache.hadoop.ipc.RemoteException: java.io.IOException: File
/mnt/hadoop/mapred/system/jobtracker.info could only be replicated to 0
nodes,
instead of 1
at
2009-09-03 18:55:48,628 WARN org.apache.hadoop.hdfs.DFSClient:
NotReplicatedYetException sleeping
/mnt/hadoop/mapred/system/jobtracker.info retries left 4
2009-09-03 18:55:49,030 INFO org.apache.hadoop.hdfs.DFSClient:
org.apache.hadoop.ipc.RemoteException: java.io.IOException: File
/mnt/hadoop/mapred/system/jobtracker.info could only be replicated to 0
nodes,
instead of 1
the JT isn't up as the datanodes aren't taking data, JT spins waiting
for files to be writeable so it can save state.
I cheat in my clusters by running a (small) datanode in the root VM, so
it will come up without needing any more.
check more about the DN/HDFS status, that looks like the first problem.
