Centos7：安装Mysql_centos安装mysql执行journalctl -xe报错mysql.service:contr

wget \
https://cdn.mysql.com/archives/mysql-5.7/mysql-community-client-5.7.32-1.el7.x86_64.rpm \
https://cdn.mysql.com/archives/mysql-5.7/mysql-community-common-5.7.32-1.el7.x86_64.rpm \
https://cdn.mysql.com/archives/mysql-5.7/mysql-community-libs-5.7.32-1.el7.x86_64.rpm \
https://cdn.mysql.com/archives/mysql-5.7/mysql-community-libs-compat-5.7.32-1.el7.x86_64.rpm \
https://cdn.mysql.com/archives/mysql-5.7/mysql-community-server-5.7.32-1.el7.x86_64.rpm

从官网下载软件包

• 把他们下载到 CentOS 的 /usr/local/src 目录下，如图显示
  

• 然后安装这些安装包，注意有依赖，需要联网
  使用命令：

  yum install -y mysql-community-*-5.7.32-1.el7.x86_64.rpm
  

  看到这个画面表示安装成功
  

• 开启服务器并初始化密码，使用的命令和命令详解：

  # 开启MySQL服务器
  systemctl start mysqld
  

 开启失败会提示Job for mysqld.service failed because the control process exited with error，请输入systemctl status mysqld.service 或者 journalctl -xn查看详细情况，

输入后发现我遇到的问题是Fatal error: mysql.user table is damaged. Please run mysql_upgrade.
解决办法：
[root@localhost ~]# rm -fr /var/lib/mysql

然后重启

也有其他同学遇到端口被占用的情况，那就kill掉再启动就行

 # 查看默认生成的密码
cat /var/log/mysqld.log | grep password

• 使用该密码登录本地 MySQL 服务器，使用命令：

  然后输入以下命令修改默认密码：mysql -uroot -p 然后输入默认的密码

• # 设置密码等级
  set global validate_password_length=4;
  set global validate_password_policy=0;
  # 修改默认密码，注意替换后面的密码
  ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY '您的密码';
  

  我们退出后发现密码已经设置完成

• 设置 root 账户远程登陆（此步骤如果不需要可以跳过），进入到 MySQL 命令行使用命令：

  use `mysql`;
  # 注意将密码替换掉
  GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' IDENTIFIED BY '您的密码' WITH GRANT OPTION;
  FLUSH PRIVILEGES;
  

• 现在我们使用 show variables like 'character%'; 命令查看字符集看到一些字符集默认还是拉丁文，我们需要将他们改成 UTF-8：
  我们修改 /etc/my.cnf 文件来修改这个配置，使用命令：

  vim /etc/my.cnf
  

  修改之后：

  # For advice on how to change settings please see
  # http://dev.mysql.com/doc/refman/5.7/en/server-configuration-defaults.html
  [client]
  default-character-set=utf8
   
  [mysql]
  default-character-set=utf8
   
  [mysqld]
  character-set-server=utf8
  #
  # 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
   
  # 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
  

  重点注意修改部分：

  [client]
  default-character-set=utf8
   
  [mysql]
  default-character-set=utf8
   
  [mysqld]
  character-set-server=utf8
  

  使用命令 systemctl restart mysqld 重启MySQL服务器后再查看：