centos8部署MySQL5.7故障集 _MySQL5.7

青春须早为，岂能长少年。这篇文章主要讲述centos8部署MySQL5.7故障集相关的知识，希望能为你提供帮助。
在centos8系统上安装mysql，使用的是centos7上安装MySQL的脚本，出现了以下问题，以做记录：
问题一：日志文件不存在，MySQL无法启动
错误日志：

[root@confluence packages]# /etc/init.d/mysqld restart ERROR! MySQL server PID file could not be found! Starting MySQL.2022-01-15T03:58:44.753030Z mysqld_safe error: log-error set to /var/log/mariadb/mariadb_error.log, however file dont exists. Create writable for user mysql. ERROR! The server quit without updating PID file (/home/confluence/mysql/mysql_data/confluence.pid).

原因和解决方法：根据日志提示，MySQL无法启动是因为指定的日志文件/var/log/mariadb/mariadb_error.log不存在
touch创建/var/log/mariadb/mariadb_error.log，并修改权限为mysql:mysql，该错误解决。
问题二：/etc/my.cnf文件为空，MySQL无法启动
错误日志：

[root@confluence packages]# /etc/init.d/mysqld start Starting MySQL.. ERROR! The server quit without updating PID file (/home/confluence/mysql/mysql_data/confluence.pid). [root@confluence packages]#

原因和解决方法：原因是/etc/my.cnf文件是空的，什么配置都没有。
查看/etc/my.cnf，文件没有配置数据目录等信息，文件内容如下：

[root@confluence mysql]# cat /etc/my.cnf # # This group is read both both by the client and the server # use it for options that affect everything # [client-server]# # include all files from the config directory # !includedir /etc/my.cnf.d[root@confluence mysql]#

/etc/my.cnf.d目录下只存在client.cnf一个文件，内容也是空的：

[root@confluence mysql]# cat /etc/my.cnf.d/client.cnf # # These two groups are read by the client library # Use it for options that affect all clients, but not the server # [client] # This group is not read by mysql client library, # If you use the same .cnf file for MySQL and MariaDB, # use it for MariaDB-only client options [client-mariadb][root@confluence mysql]#

把/etc/my.cnf文件补充完整，问题即解决。
问题三：/etc/my.cnf文件权限过大导致MySQL无法启动
错误日志：

[root@confluence etc]# /etc/init.d/mysqld start my_print_defaults: [Warning] World-writable config file /etc/my.cnf is ignored. Starting MySQL.my_print_defaults: [Warning] World-writable config file /etc/my.cnf is ignored. my_print_defaults: [Warning] World-writable config file /etc/my.cnf is ignored. .. ERROR! The server quit without updating PID file (/home/confluence/mysql/mysql_data/confluence.pid). [root@confluence etc]#

原因和解决方法：【centos8部署MySQL5.7故障集】原因是因为/etc/my.cnf文件是从其它节点拷贝拷贝过来的，上传后默认的权限过大。把/etc/my.cnf文件的权限改成644，重新启动MySQL则成功。