这个问题花费了我将近两天的时间，经过多次试错和尝试，现在想分享给大家来解决此问题避免大家入坑，以前都是在局域网上搭建的hadoop集群，并且是局域网访问的，没遇见此问题。
因为阿里云上搭建的hadoop集群，需要配置映射集群经过内网访问，也就是局域网的ip地址。
如果配置为公网IP地址，就会出现集群启动不了，namenode和secondarynamenode启动不了，如果将主机的映射文件配置为内网IP集群就可以正常启动了。但通过eclipse开发工具访问
会出错，显示了阿里云内网的ip地址来访问datanode，这肯定访问不了啊，这问题真实醉了，就这样想了找了好久一致没有思路。
最终发现需要在hdfs-site.xml中修改配置项dfs.client.use.datanode.hostname设置为true，就是说客户端访问datanode的时候是通过主机域名访问，就不会出现通过内网IP来访问了
最初查看日志发现：
一、查看日志
1. less hadoop-hadoop-namenode-master.log
2.less hadoop-hadoop-secondarynamenode-master.log
二、解决集群访问问题
1.查看hosts映射文件
上面是公网IP需要替换为内网IP
然后正常搭建hadoop集群
2.core-site.xml
fs.defaultFS hdfs://master:9000 hadoop.tmp.dir /home/hadoop/BigData/hadoop-2.7.3/data
3.hadoop-env.sh 修改export JAVA_HOME值
export JAVA_HOME=/home/hadoop/BigData/jdk1.8
4.hdfs-site.xml 注意：添加一个dfs.client.use.datanode.hostname配置
dfs.namenode.secondary.http-address master:50090 dfs.replication 1 dfs.permissions false dfs.client.use.datanode.hostname true only cofig in clients
5.mapred-site.xml
mapreduce.framework.name yarn mapreduce.jobhistory.address master:10020 mapreduce.jobhistory.webapp.address master:19888
6. yarn-site.xml
yarn.resourcemanager.hostname master yarn.nodemanager.aux-services mapreduce_shuffle
7.hadoop namenode -format格式化，然后启动start-all.sh
8.在本地IDE环境中编写单词统计测试集群访问
public class WordCount { public static class TokenizerMapper extends Mapper { private final static IntWritable one = new IntWritable(1); private Text word = new Text(); @Override protected void map(LongWritable key, Text value, Mapper .Context context) throws IOException, InterruptedException { StringTokenizer itr = new StringTokenizer(value.toString()); while(itr.hasMoreTokens()) { word.set(itr.nextToken()); context.write(word, one); } } public static class WordCountReducer extends Reducer { private IntWritable result = new IntWritable(); @Override protected void reduce(Text key, Iterable values, Reducer .Context context) throws IOException, InterruptedException { int sum = 0; for(IntWritable item:values) { sum += item.get(); } result.set(sum); context.write(key, result); } } public static void main(String[] args) throws IOException, ClassNotFoundException, InterruptedException { Configuration conf = new Configuration(); String[] otherArgs = new GenericOptionsParser(conf, args).getRemainingArgs(); if(otherArgs.length < 2) { System.err.println("Usage: wordcount [ ....] "); System.exit(2); } Job job = Job.getInstance(conf, "word count"); job.setJarByClass(WordCount.class); job.setMapperClass(TokenizerMapper.class); job.setCombinerClass(WordCountReducer.class); job.setReducerClass(WordCountReducer.class); job.setOutputKeyClass(Text.class); job.setOutputValueClass(IntWritable.class); for(int i = 0; i < otherArgs.length -1; i++) { FileInputFormat.addInputPath(job, new Path(otherArgs[i])); } FileSystem fs = FileSystem.get(conf); Path output = new Path(otherArgs[otherArgs.length - 1]); if(fs.exists(output)) { fs.delete(output, true); System.out.println("output directory existed! deleted!"); } FileOutputFormat.setOutputPath(job, output); System.exit(job.waitForCompletion(true) ? 0 : 1); } }} 9.运行的时候配置一个数据的存放路径和数据的输出路径位置
