這時候，不妨打開MySQL的告警日志，畢竟，只要MySQL服務啟動，告警日志都會有輸出信息的，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服務在啟動的時候，不能創建pid文件。
在終端看一下該目錄是否存在，果然，不存在。
于是，創建了/var/run/mysqld/目錄，重啟MySQL服務
[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]
依舊報錯，重新查看告警日志，有以下輸出
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
原來，/var/run/mysqld/的屬主和屬組還是root，mysql并不能在其中創建文件，后修改該目錄的屬主和屬組，啟動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 ]
總結：
以前在玩Kubernetes的時候，常遇到啟動失敗的情況，根據systemctl的提示，通過systemctl status mysqld.service和journalctl -xe命令查看服務啟動失敗的原因往往并不如人意，反而給了一種錯誤的暗示，以為這個跟系統有關。其實，通過查看服務的日志，往往更能清晰的知道服務啟動失敗的原因
posted on 2018-05-10 15:23
長春語林科技 閱讀(201)
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