分析问题可能出现的原因：

1.mysql启动时找不到Socket 需要在 /etc/my.cnf 中配置socket文件位置位置

        

因为我配置过了socket所以问题不出现在此：

继续寻找：

想要重启一下mysqld 看看是不是就能回复了

        service mysqld   restart 

[root@node0 ~]# service mysqld restart
Restarting mysqld (via systemctl):  Job for mysqld.service failed because the control process exited with error code. See "systemctl status mysqld.service" and "journalctl -xe" for details.

出现问题

[root@node0 ~]# systemctl status mysqld.service
● mysqld.service - SYSV: MySQL database server.
   Loaded: loaded (/etc/rc.d/init.d/mysqld; bad; vendor preset: disabled)
   Active: failed (Result: exit-code) since 日 2022-03-20 21:42:33 CST; 10s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 1481 ExecStart=/etc/rc.d/init.d/mysqld start (code=exited, status=1/FAILURE)

3月 20 21:42:32 node0 systemd[1]: Starting SYSV: MySQL database server....
3月 20 21:42:33 node0 mysqld[1481]: MySQL Daemon failed to start.
3月 20 21:42:33 node0 mysqld[1481]: Starting mysqld:  [失败]
3月 20 21:42:33 node0 systemd[1]: mysqld.service: control process exited, code=exited status=1
3月 20 21:42:33 node0 systemd[1]: Failed to start SYSV: MySQL database server..
3月 20 21:42:33 node0 systemd[1]: Unit mysqld.service entered failed state.
3月 20 21:42:33 node0 systemd[1]: mysqld.service failed.

查看mysql.log

/var/log/mysqld.log

2022-03-20T12:47:49.951230Z 0 [ERROR] /usr/sbin/mysqld: Can't create/write to file '/var/run/mysqld/mysqld.pid' (Errcode: 2 - No such file or directory)
2022-03-20T12:47:49.951238Z 0 [ERROR] Can't start server: can't create PID file: No such file or directory

解决

mkdir -p /var/run/mysqld/
chown mysql.mysql /var/run/mysqld/

service mysqld restart

登录又出现问题了  明明密码和用户名都对就是死活登录不上去

然后就去各种想办法  看看到底是删了重新安装还是说继续解决下去  毕竟都到这步了

跳过安全

mysqld_safe --skip-grant-tables
打开另一个客户端  连接mysql 进行密码的修改

mysql -uroot

use mysql

update user set authentication_string=password('281956') , host='#' where user='root';

flush privileges;  

退出mysql

再重新启动即可

service mysqld restart