hadoop中HDFS文件系统 nameNode出现的问题 nameNode无法打开

1，修改core-site.xml文件，先改成localhost，将所有进程关闭stop-all.sh（或者是先关闭所有进程，然后再修改文件），然后重启，在修改core-site.xml文件成ip地址。
注意：修改core-site文件的之后，如果出现问题，则重启
文件内容：
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->

<!-- Put site-specific property overrides in this file. -->

<configuration>
<property>
<name>hadoop.tmp.dir</name>
<value>file:/usr/local/hadoop/tmp</value>
<description>Abase for other temporary directories.</description>
</property>
<property>
<name>fs.defaultFS</name>
<value>hdfs://192.168.21.128:9000</value>
</property>

</configuration>

2，删除temp目录中的所有内容
rm -r ./tmp
格式化namenode
./bin/hdfs namenode -format
重启start-all.sh

以上两点顺序不确定