Hadoop: each namenode and datanode only last for a momentary time - linux

Question

Using CentOs 5.4
Three virtual machines(using vmware workstation):master, slave1, slave2. master is used for the namenode, and slave1 slave2 are used for the datanodes.
Hadoop version is hadoop-0.20.1.tar.gz, I have configured all the relative files, and closed the firewall with root user using the command:/sbin/service iptables stop. Then I tried to format namenode and start hadoop in the master(namenode) virtual machine with the following commands, no error was reported.
bin/hadoop namenode -format
bin/start-all.sh
Then I typed the command "jps" in the master machine right now, and found the right result:
5144 JobTracker
4953 NameNode
5079 SecondaryNameNode
5216 Jps
But after about several seconds, when I tried to type the "jps" command, all the virtual machines only have one process: JPS. The following is the result displayed in the namenode(master)
5236 Jps
What's the matter? Or how can I find what caused the matter? Dose it mean that it cannot find any namenode or datanode? Thank you.
Attachment: all the places I have modified:
hadoop-env.sh:
# set java environment
export JAVA_HOME=/usr/jdk1.6.0_13/
core-site.xml:
<configuration>
<property>
<name>master.node</name>
<value>namenode_master</value>
<description>master</description>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>/usr/local/hadoop/tmp</value>
<description>local dir</description>
</property>
<property>
<name>fs.default.name</name>
<value>hdfs://${master.node}:9000</value>
<description> </description>
</property>
</configuration>
hdfs-site.xml:
<configuration>
<property>
<name>dfs.replication</name>
<value>2</value>
</property>
<property>
<name>dfs.name.dir</name>
<value>${hadoop.tmp.dir}/hdfs/name</value>
<description>local dir</description>
</property>
<property>
<name>dfs.data.dir</name>
<value>${hadoop.tmp.dir}/hdfs/data</value>
<description> </description>
</property>
</configuration>
mapred-site.xml:
<configuration>
<property>
<name>mapred.job.tracker</name>
<value>${master.node}:9001</value>
<description> </description>
</property>
<property>
<name>mapred.local.dir</name>
<value>${hadoop.tmp.dir}/mapred/local</value>
<description> </description>
</property>
<property>
<name>mapred.system.dir</name>
<value>/tmp/mapred/system</value>
<description>hdfs dir</description>
</property>
</configuration>
master:
master
slaves:
slave1
slave2
/etc/hosts:
192.168.190.133 master
192.168.190.134 slave1
192.168.190.135 slave2

Answer 1

From the log files, I found that I should change the namenode_master to master in the file core-site.xml. Now it works.