[Linux服务器使用] Linux 安装mysql数据库

CentOS7默认数据库是mariadb, 但是 好多用的都是mysql ，但是CentOS7的yum源中默认好像是没有mysql的

1. 卸载 先停掉mysql进程 没有安装过的可以直接跳过！

    pkill -9 mysqld
    rpm -qa|grep -i mysql
   

   用命令yum -y remove 卸载mysql文件
   卸载不掉的用 rpm -ev 卸载
   一直卸载到没有

2. 下载mysql的repo源 这次安装的时mysql5.7.20

    [root@localhost ~]# cd /usr/local/src/
    [root@localhost src]# wget http://repo.mysql.com/mysql57-community-release-el7-8.noarch.rpm
    [root@localhost src]# rpm -ivh mysql57-community-release-el7-8.noarch.rpm
    [root@localhost src]# yum -y install mysql-server 
    //也可以指定安装目录    
    yum --installroot=/usr/local/mysql --releasever=/ -y install mysql-server
   

我没试，这样装环境变量配置都不用你管，装上直接启动就行。安装路径是默认的。

默认配置文件路径：

• 配置文件：/etc/my.cnf
• 日志文件：/var/log/var/log/mysqld.log
• 服务启动脚本：/usr/lib/systemd/system/mysqld.service
• socket文件：/var/run/mysqld/mysqld.pid

3. 配置my.cnf

    vim /etc/my.cnf
    [mysqld]
    #
    # Remove leading # and set to the amount of RAM for the most important data  
    # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.  
    # innodb_buffer_pool_size = 128M  
    #
    # Remove leading # to turn on a very important data integrity option: logging  
    # changes to the binary log between backups. 
    # log_bin  
    #  
    # Remove leading # to set options mainly useful for reporting servers.  
    # The server defaults are faster for transactions and fast SELECTs.  
    # Adjust sizes as needed, experiment to find the optimal values.  
    # join_buffer_size = 128M  
    # sort_buffer_size = 2M  
    # read_rnd_buffer_size = 2M  
    datadir=/var/lib/mysql  
    socket=/var/lib/mysql/mysql.sock  
    server_id = 1  
    expire_logs_days = 3  
    # Disabling symbolic-links is recommended to prevent assorted security risks  
    symbolic-links=0  
    log-error=/var/log/mysqld.log  
    pid-file=/var/run/mysqld/mysqld.pid  
   

4. 启动mysql服务

    service mysqld restart
    //检查mysql 的运行状态
    service mysqld status
    systemctl status mysqld.service
    //获取临时密码
    grep 'temporary password' /var/log/mysqld.log
    //使用密码登录
    mysql -uroot -p
    //登录后必须马上修改密码，不然会报错误1820
    //修改密码太简单会报错1819
    ALTER USER 'root'@'localhost' IDENTIFIED BY 'root';
    //解决方案
    //首先，修改validate_password_policy参数的值
    mysql> set global validate_password_policy=0; 
    //再修改密码的长度
    set global validate_password_length=1;
    //再次执行修改密码就可以了
    ALTER USER 'root'@'localhost' IDENTIFIED BY 'root';
    //授权其他机器登陆
    GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY 'root' WITH GRANT OPTION;
    //最后记得刷新权限；
    FLUSH  PRIVILEGES;
    //同样修改的host的方式还有这个更新数据库
    mysql> update user set host='%' where user='root' and host='localhost'; 
    mysql> flush privileges;