Solution to MySQL Service Startup failure in CentOS 7, centosmysql

Solution to MySQL Service Startup failure in CentOS 7, centosmysql

Failed to start MySQL server today, as shown below:

[root@spark01 ~]# /etc/init.d/mysqld startStarting 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]

Use systemctl status mysqld. service and journalctl-xe as prompted to view the cause of service Startup failure.

[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=1Jan 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/1Jan 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 :1.25Jan 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=1Jan 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.

However, unfortunately, this information does not provide the real cause of Service Startup failure.

At this time, you may wish to open the MySQL alarm log. After all, as long as the MySQL service is started, the alarm log will have output information.

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 directory160120 18:00:20 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended

When MySQL is started, the pid file cannot be created.

Check whether the directory exists on the terminal.

Therefore, the/var/run/mysqld/directory is created and the MySQL service is restarted.

[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]

An error is still reported. Check the alarm log again, with the following output:

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 denied160120 18:28:37 mysqld_safe mysqld from pid file /var/run/mysqld/mysqld.pid ended160120 18:32:06 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

It turns out that the owner and group of/var/run/mysqld/are still root. mysql cannot create files in the directory, modify the owner and group of the directory, and start 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 startStarting mysqld (via systemctl):                           [  OK  ]

 

Summary:

In the past, when playing with Kubernetes, we often encountered startup failures. According to the systemctl prompt, use systemctl status mysqld. the service and journalctl-xe commands often fail to check the cause of service Startup failure. Instead, they give an error suggestion that this is related to the system. In fact, by viewing service logs, you can better understand the cause of Service Startup failure.