安装Hadoop（伪分布式环境）namenode和datanode无法启动解决方案
先附上我参考的安装教程链接
10.1.88.4/index_1.php?url=/redirect
我在执行./之后发现，没有任何错误提示，输入jps得到如下结果：
[hadoop@localhost sbin]$ ./
This script is Deprecated. Instead use and
Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/software/hadoop_install/hadoop/logs/
localhost: starting datanode, logging to /usr/software/hadoop_install/hadoop/logs/
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/software/hadoop_install/hadoop/logs/
starting yarn daemons
resourcemanager running as process 21995. Stop it first.
localhost: nodemanager running as process 22133. Stop it first.
[hadoop@localhost sbin]$ jps
22133 NodeManager
23848 Jps
21995 ResourceManager
明显没有datanode和namenode，上网找了很多方法都没用。
按照网上的方法，我就查看文件夹data/tmp/data发现我根本没有这个目录。一脸懵逼。
我只好查看$HADOOP_HOME/log里面的文件，查看有关于datanode和namenode的日志，
我先查看的是datanode的日志，
有点多，直接划到最后，（看我加粗字体）
2019-11-02 17:35:59,401 INFO : registered UNIX signal handlers for [TERM, HUP, INT]
2019-11-02 17:36:00,195 WARN : Invalid /usr/software/hadoop_install/hadoop/data/dfs/data :
: File file:/usr/software/hadoop_install/hadoop/data/dfs/data does not exist
at (:635)
at (:861)
at (:625)
at (:442)
at (:233)
at (:141)
at (:116)
at $(:2580)
at (:2622)
at (:2604)
at (:2497)
at (:2544)
at (:2729)
at (:2753)
2019-11-02 17:36:00,207 ERROR : Exception in secureMain
: All directories in are invalid: "/usr/software/hadoop_install/hadoop/data/dfs/data"
at (:2631)
at (:2604)
at (:2497)
at (:2544)
at (:2729)
at (:2753)
2019-11-02 17:36:00,208 INFO : Exiting with status 1
2019-11-02 17:36:00,216 INFO : SHUTDOWN_MSG:
/************************************************************
SHUTDOWN_MSG: Shutting down DataNode at localhost/127.0.0.1
************************************************************/
[hadoop@localhost logs]$
我顿时恍然大悟，，肯定是权限不够，看不到data，我立马回到hadoop的安转目录下查看文件的权限情况
[hadoop@localhost hadoop]$ ls -l
总用量 128
drwxr-xr-x. 2 hadoop hadoop 194 11月 2 17:50 bin
drwxr-xr-x. 2 root root 6 11月 2 16:58 data
drwxr-xr-x. 3 hadoop hadoop 20 11月 2 16:57 etc
drwxr-xr-x. 2 hadoop hadoop 106 9月 10 2018 include
drwxr-xr-x. 3 hadoop hadoop 20 9月 10 2018 lib
drwxr-xr-x. 2 hadoop hadoop 239 9月 10 2018 libexec
-rw-r--r--. 1 hadoop hadoop 99253 9月 10 2018
drwxrwxr-x. 3 hadoop hadoop 4096 11月 2 17:36 logs
-rw-r--r--. 1 hadoop hadoop 15915 9月 10 2018
-rw-r--r--. 1 hadoop hadoop 1366 9月 10 2018
drwxr-xr-x. 2 hadoop hadoop 4096 9月 10 2018 sbin
drwxr-xr-x. 4 hadoop hadoop 31 9月 10 2018 share
drwxr-xr-x. 2 root root 27 11月 2 16:23 test
果然 ，根据红色字体能发现，data的权限所有者是root的，hadoop根本就不能操作，我就想肯定是一开始创建的时候滥用了root用户
到这里就很简单了，两行命令即可：
# 修改文件权限拥有者，hadoop是我的用户名，data是文件夹名字
sudo chown -R hadoop data
# 修改文件权限组
sudo chgrp -R hadoop data修改过后，查看一下修改结果，可以看到修改成功：
[hadoop@localhost hadoop]$ ls -l
总用量 128
drwxr-xr-x. 2 hadoop hadoop 194 11月 2 17:50 bin
drwxr-xr-x. 2 hadoop hadoop 6 11月 2 16:58 data
drwxr-xr-x. 3 hadoop hadoop 20 11月 2 16:57 etc
drwxr-xr-x. 2 hadoop hadoop 106 9月 10 2018 include
drwxr-xr-x. 3 hadoop hadoop 20 9月 10 2018 lib
drwxr-xr-x. 2 hadoop hadoop 239 9月 10 2018 libexec
-rw-r--r--. 1 hadoop hadoop 99253 9月 10 2018
drwxrwxr-x. 3 hadoop hadoop 4096 11月 2 17:36 logs
-rw-r--r--. 1 hadoop hadoop 15915 9月 10 2018
-rw-r--r--. 1 hadoop hadoop 1366 9月 10 2018
drwxr-xr-x. 2 hadoop hadoop 4096 9月 10 2018 sbin
drwxr-xr-x. 4 hadoop hadoop 31 9月 10 2018 share
drwxr-xr-x. 2 root root 27 11月 2 16:23 test
然后再回去停止刚才执行的所有node
[hadoop@localhost sbin]$ ./
This script is Deprecated. Instead use and
Stopping namenodes on [localhost]
localhost: no namenode to stop
localhost: no datanode to stop
Stopping secondary namenodes [0.0.0.0]
0.0.0.0: no secondarynamenode to stop
stopping yarn daemons
stopping resourcemanager
localhost: stopping nodemanager
localhost: nodemanager did not stop gracefully after 5 seconds: killing with kill -9
no proxyserver to stop
最后就是启动所有node
[hadoop@localhost sbin]$ ./
This script is Deprecated. Instead use and
Starting namenodes on [localhost]
localhost: starting namenode, logging to /usr/software/hadoop_install/hadoop/logs/
localhost: starting datanode, logging to /usr/software/hadoop_install/hadoop/logs/
Starting secondary namenodes [0.0.0.0]
0.0.0.0: starting secondarynamenode, logging to /usr/software/hadoop_install/hadoop/logs/
starting yarn daemons
starting resourcemanager, logging to /usr/software/hadoop_install/hadoop/logs/
localhost: starting nodemanager, logging to /usr/software/hadoop_install/hadoop/logs/
输入jps命令查看启动情况：
[hadoop@localhost sbin]$ jps
36534 DataNode
36343 NameNode
37097 NodeManager
36762 SecondaryNameNode
36954 ResourceManager
37422 Jps
可以看到所有的DataNode和NameNode都已经成功启动。
激动万分，终于弄出来了，哈哈大家要是哪里对不上或者是有其他问题，可以留言问我，我最近装这个装了好几遍哈哈。