Hadoop(2)---Mysql 在Linux下的安装与配置

Linux下安装Mysql相对windows较为复杂，折腾了2天多，终于安装和配置完成，简单记录安装和配置过程，如下：

Ⅰ.操作环境说明：

 Linux:CentOS6.5_64 bit                                      
 Mysql:mysql-5.6.36-linux-glibc2.5-x86_64.tar.gz

Ⅱ.安装过程：

安装mysql前，先用 rpm -qa | grep mysql 查看系统自带的mysql-libs;然后用 rpm -e --nodeps mysql-libs-XXX-el6-xxx;删除自带的mysql库; 网上安装的贴子多不胜数，安装的文件夹也很乱，在此统一说明，Mysql默认安装环境:/usr/local/mysql;无特殊情况不建议更换，安装至其它自定义目录，还要修改相关的配置文件，作为新手，我安装至默认目录：

①Install MySQL binary distribution:

shell> groupadd mysql 
shell> useradd -r -g mysql -s /bin/false mysql
shell> cd /usr/local
shell> tar -xzvf   mysql-5.6.36-linux-glibc2.5-x86_64.tar.gz  #解压后直接更名为mysql
shell> cd mysql
shell> mkdir mysql-files
shell> chmod 770 mysql-files
shell> chown -R mysql .
shell> chgrp -R mysql .
shell> ./scripts/mysql_install_db --user=mysql    # Before MySQL 5.7.6  //安装mysql
shell> chown -R root .
shell> chown -R mysql data mysql-files
shell> bin/mysqld_safe --user=mysql & 
shell> cp support-files/mysql.server /etc/init.d/mysql.server
shell> cp bin/mysql  /etc/init.d/mysql  
                                            #执行后可通过 service mysql -u user -p 登陆mysql
shell> chkconfig  /etc/init.d/mysql.server   on    #设置mysql.server开机启动

②mysql常用命令：

          ps -A | grep mysql            #查看mysql服务进程, 得到 mysql进程的PID;
          kill -9 PID1 PID2...PIDn      #终止mysql进程;
          /etc/init.d/mysql.server     start/stop/restart   #启动/停止/重启mysql服务：  
          service mysql -u root -p      #登录mysql:

③mysql初次登录：

                 bin/mysqladmin  -u root password ' password'     #设置root密码

④安装过程分析：

To start mysqld at boot time you have to copy support-files/mysql.server to the right place for 
your system

   PLEASE REMEMBER TO SET A PASSWORD FOR THE MySQL root USER !
        To do so, start the server, then issue the following commands:
                   ./bin/mysqladmin -u root password 'new-password'
                 　./bin/mysqladmin -u root -h hostname  password 'new-password'

        You can start the MySQL daemon with:
                           cd . ; ./bin/mysqld_safe &
        You can test the MySQL daemon with mysql-test-run.pl
                           cd mysql-test ; perl mysql-test-run.pl

New default config file was created as ./my.cnf and will be used by default by the server when you start it.
You may edit this file to change server settings

my.cnf文件很值得一谈,Mysql5.7.6以后不再生成my.cnf文件，安装包中也没有了my-default.cnf文件，my.cnf文件可以保存用户的自定义设置,my.cnf文件存在与多个位置；安装过程中生成的my.cnf存在于/usr/local/mysql/my.cnf;

Default options are read from the following files in the given order:
    /etc/my.cnf  =>  /etc/mysql/my.cnf   => /usr/local/mysql/etc/my.cnf =>  ~/.my.cnf 
    my.cnf文件的读取顺序，后面的文件配置会覆盖前面的文件配置；

Ⅲ.设置mysql默认字符集：

查看字符集: show variables like 'character_%';

①修改my.cnf （/usr/local/mysql/my.cnf）：

 [client]
 ...
                                      default_character_set=utf8

 [mysqld]
 ...
                                      character_set_server=utf8 
 [mysql]
 ...
                                      default_character_set=utf8

②cp my.cnf /etc/my.cnf#将my.cnf拷贝至/etc下

③vi /etc/my.cnf

将最后一行sql_mode用’#‘注释掉;此时，mysql 默认字符集已全改为utf8

Ⅳ.安装&配置过程中常见错误：

①ERROR 2002 (HY000)：

Can't connect to local MySQL server through socket '/tmp/mysql.sock' (2)。

error: 'Can't connect to local MySQL server through socket'/tmp/mysql.sock' (2)'。

Check that mysqld is running and that the socket: '/tmp/mysql.sock' exists!

解决办法：启动mysql.server服务

      ps -A |grep mysql                        #得到mysql 的Pid
      kill -9 Pid1 Pid2                        #终止mysql进程;
     /etc/init.d/mysql.server restart          #启动mysql.server服务

②ERROR 1045 (28000):

Access denied for user 'root'@'localhost' (using password: NO)

 shell>>  /etc/init.d/mysql stop
 shell>>  mysqld_safe --user=mysql --skip-grant-tables --skip-networking &
 shell>>  mysql -u root mysql
 mysql>   UPDATE user SET Password=PASSWORD('newpassword') where USER='root';
 mysql>   mysql> FLUSH PRIVILEGES;
 mysql>   quit
 shell>>  /etc/init.d/mysql restart

③ /etc/init.d/mysql restart执行失败

Starting MySQL...The server quit without updating PID file [失败]local/mysql/data/hostname.pid).

   vi my.cnf
   [mysqld]
              ...
              default_character_set=utf8 改为 character_set_server=utf8

④service mysql -u root -p 登录失败

/etc/init.d/mysql: unknown variable'sql_mode=NO_ENGINE_SUBSTITUTI ON，STRICT_TRANS_TABLES'

将/etc/my.cnf 中最后一句 sql_mode=XXXXX;用‘#’注释掉

---End---