报错信息

登陆数据库报错：`

ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (2 "No such file or directory")`

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重启服务报错：Job for mariadb.service failed because the control process exited with error code. See "systemctl status mariadb.service" and "journalctl -xe" for details.

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查看服务状态信息：`systemctl status mariadb.service

● mariadb.service - MariaDB 10.1 database server

Loaded: loaded (/usr/lib/systemd/system/mariadb.service; disabled; vendor preset: disabled)Active: failed (Result: exit-code) since Mon 2019-04-15 17:16:38 UTC; 4s agoProcess: 2864 ExecStartPre=/usr/libexec/mysql-prepare-db-dir %n (code=exited, status=1/FAILURE)Process: 2841 ExecStartPre=/usr/libexec/mysql-check-socket (code=exited, status=0/SUCCESS)

Apr 15 17:16:37 xiandian systemd[1]: Starting MariaDB 10.1 database server...

Apr 15 17:16:38 xiandian mysql-prepare-db-dir[2864]: Database MariaDB is not initialized, but the directory /var/lib/mysql is not empty...e done.Apr 15 17:16:38 xiandian mysql-prepare-db-dir[2864]: Make sure the /var/lib/mysql is empty before running mysql-prepare-db-dir.Apr 15 17:16:38 xiandian systemd[1]: mariadb.service: control process exited, code=exited status=1Apr 15 17:16:38 xiandian systemd[1]: Failed to start MariaDB 10.1 database server.Apr 15 17:16:38 xiandian systemd[1]: Unit mariadb.service entered failed state.Apr 15 17:16:38 xiandian systemd[1]: mariadb.service failed.Hint: Some lines were ellipsized, use -l to show in full.`

重启服务日志报错信息：`Apr 15 17:16:21 xiandian mysql-prepare-db-dir: Database MariaDB is not initialized, but the directory /var/lib/mysql is not empty, so initialization cannot be done.

Apr 15 17:16:21 mysql-prepare-db-dir: Make sure the /var/lib/mysql is empty before running mysql-prepare-db-dir.

Apr 15 17:16:21 systemd: mariadb.service: control process exited, code=exited status=1Apr 15 17:16:21 systemd: Failed to start MariaDB 10.1 database server.Apr 15 17:16:21 systemd: Unit mariadb.service entered failed state.Apr 15 17:16:21 systemd: mariadb.service failed.`

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可以看到报错信息中提示数据库未初始化，但/var/lib/mysql不为空，所以无法进行初始化。

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去看一下这个目录权限

ll /var/lib/ d---------. 11 mysql      mysql      4096 May  4  2018 mysql

mysql权限为0，导致启动文件sock文件无法写入进去

重启赋予目录权限为755chmod 755 /var/lib/mysql/然后再重启一下mysql服务systemctl restart mariadb.serviceps -e | grep -i mysql3191 ? 00:00:02 mysqld正常启动