CentOS 7下MySQL服务启动失败的快速解决方法
编程学习 2021-07-05 15:28www.dzhlxh.cn编程入门
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今天，启动MySQL服务器失败，如下所示：
[root@spark01 ~]# /etc/init.d/mysqld start
Starting 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.
[FAILED]
根据提示，分别使用systemctl status mysqld.service和journalctl -xe查看服务启动失败的原因
[root@spark01 ~]# systemctl status mysqld.service
?.mysqld.service - SYSV: MySQL database server. Loaded: loaded (/etc/rc.d/init.d/mysqld) Active: failed (Result: exit-code) since Wed 2016-01-20 18:26:57 CST; 40s ago Docs: man:systemd-sysv-generator(8) Process: 2979 ExecStart=/etc/rc.d/init.d/mysqld start (code=exited, status=1/FAILURE) Jan 20 18:26:56 spark01 systemd[1]: Starting SYSV: MySQL database server.... Jan 20 18:26:57 spark01 mysqld[2979]: MySQL Daemon failed to start. Jan 20 18:26:57 spark01 mysqld[2979]: Starting mysqld: [FAILED] Jan 20 18:26:57 spark01 systemd[1]: mysqld.service: control process exited, code=exited status=1 Jan 20 18:26:57 spark01 systemd[1]: Failed to start SYSV: MySQL database server.. Jan 20 18:26:57 spark01 systemd[1]: Unit mysqld.service entered failed state. Jan 20 18:26:57 spark01 systemd[1]: mysqld.service failed.
[root@spark01 ~]# journalctl -xe
-- -- Unit session-2.scope has begun starting up. Jan 20 18:26:48 spark01 sshd[2916]: pam_unix(sshd:session): session opened for user spark by (uid=0) Jan 20 18:26:52 spark01 su[2944]: (to root) spark on pts/1 Jan 20 18:26:52 spark01 su[2944]: pam_unix(su-l:session): session opened for user root by spark(uid=1000) Jan 20 18:26:56 spark01 polkitd[909]: Registered Authentication Agent for unix-process:2974:117137 (system bus name :1.25 Jan 20 18:26:56 spark01 systemd[1]: Starting SYSV: MySQL database server.... -- Subject: Unit mysqld.service has begun start-up -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit mysqld.service has begun starting up. Jan 20 18:26:57 spark01 mysqld[2979]: MySQL Daemon failed to start. Jan 20 18:26:57 spark01 mysqld[2979]: Starting mysqld: [FAILED] Jan 20 18:26:57 spark01 systemd[1]: mysqld.service: control process exited, code=exited status=1 Jan 20 18:26:57 spark01 systemd[1]: Failed to start SYSV: MySQL database server.. -- Subject: Unit mysqld.service has failed -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit mysqld.service has failed. -- -- The result is failed. Jan 20 18:26:57 spark01 systemd[1]: Unit mysqld.service entered failed state. Jan 20 18:26:57 spark01 systemd[1]: mysqld.service failed. Jan 20 18:26:57 spark01 polkitd[909]: Unregistered Authentication Agent for unix-process:2974:117137 (system bus name :1.
但，可惜的时，这些信息并不能提供服务启动失败的真正原因。
这时候，不妨打开MySQL的告警日志，毕竟，只要MySQL服务启动，告警日志都会有输出信息的，果然
2016-01-20T10:00:19.935771Z 0 [ERROR] /usr/sbin/mysqld: Can't create/write to file '/var/run/mysqld/mysqld.pid' (Errcode: 2 - No such file or directory) 2016-01-20T10:00:19.935795Z 0 [ERROR] Can't start server: can't create PID file: No such file or directory 160120 18:00:20 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended
MySQL服务在启动的时候，不能创建pid文件。
在终端看一下该目录是否存在，果然，不存在。
于是，创建了/var/run/mysqld/目录，重启MySQL服务
[root@spark01 ~]# mkdir -p /var/run/mysqld/
[root@spark01 ~]# /etc/init.d/mysqld start
Starting 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.
[FAILED]
依旧报错，重新查看告警日志，有以下输出
2016-01-20T10:28:37.183387Z 0 [ERROR] /usr/sbin/mysqld: Can't create/write to file '/var/run/mysqld/mysqld.pid' (Errcode: 13 - Permission denied) 2016-01-20T10:28:37.183431Z 0 [ERROR] Can't start server: can't create PID file: Permission denied 160120 18:28:37 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended 160120 18:32:06 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
原来，/var/run/mysqld/的属主和属组还是root，mysql并不能在其中创建文件，后修改该目录的属主和属组，启动OK。
[root@spark01 ~]# ls -ld /var/run/mysqld/ drwxr-xr-x 2 root root 40 Jan 20 18:28 /var/run/mysqld/ [root@spark01 ~]# chown mysql.mysql /var/run/mysqld/ [root@spark01 ~]# /etc/init.d/mysqld start Starting mysqld (via systemctl): [ OK ]
总结：
以前在玩Kubernetes的时候，常遇到启动失败的情况，根据systemctl的提示，通过systemctl status mysqld.service和journalctl -xe命令查看服务启动失败的原因往往并不如人意，反而给了一种错误的暗示，以为这个跟系统有关。其实，通过查看服务的日志，往往更能清晰的知道服务启动失败的原因。
以上这篇CentOS 7下MySQL服务启动失败的快速解决方法就是长沙网络推广分享给大家的全部内容了，希望能给大家一个参考，也希望大家多多支持狼蚁SEO。