Ubuntu 16.04 上的 MySQL 問題

Question

它昨天隨機壞了（不再啟動），我不知道如何修復它。

當我跑步時：

sudo service mysql start

它給出了這個錯誤：

Job for mysql.service failed because the control process exited with error 
code. See "systemctl status mysql.service" and "journalctl -xe" for details.

輸出systemctl status mysql.service：

● mysql.service - MySQL Community Server
   Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)<br>
   Active: inactive (dead) (Result: exit-code) since Mon 2016-09-05 15:10:31 CEST; 43s ago<br>
  Process: 6515 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=1/FAILURE)<br>
Sep 05 15:10:31 vps310084 systemd[1]: mysql.service: Service hold-off time over, scheduling restart.<br>
Sep 05 15:10:31 vps310084 systemd[1]: Stopped MySQL Community Server.<br>
Sep 05 15:10:31 vps310084 systemd[1]: mysql.service: Start request repeated too quickly.<br>
Sep 05 15:10:31 vps310084 systemd[1]: Failed to start MySQL Community Server.<br>
Sep 05 15:10:33 vps310084 systemd[1]: mysql.service: Start request repeated too quickly.<br>
Sep 05 15:10:33 vps310084 systemd[1]: Failed to start MySQL Community Server.

輸出journalctl -xe：

Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel**
--
-- Unit mysql.service has failed.
--
-- The result is failed. 
Sep 05 15:14:56 vps310084 systemd[1]: mysql.service: Unit entered failed state. 
Sep 05 15:14:56 vps310084 systemd[1]: mysql.service: Failed with result 'exit-code'.
Sep 05 15:14:56 vps310084 systemd[1]: mysql.service: Service hold-off time over, scheduling restart. 
Sep 05 15:14:56 vps310084 systemd[1]: Stopped MySQL Community Server.
-- Subject: Unit mysql.service has finished shutting down<br>
-- Defined-By: systemd
-- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel
--
-- Unit mysql.service has finished shutting down. 
Sep 05 15:14:56 vps310084 systemd[1]: mysql.service: Start request repeated too quickly. 
Sep 05 15:14:56 vps310084 systemd[1]: Failed to start MySQL Community Server.
-- Subject: Unit mysql.service has failed
-- Defined-By: systemd
--
-- Unit mysql.service has failed.
--
-- The result is failed.

Answer 1

Mysql 的 systemctl 啟動腳本無法執行此指令 /usr/share/mysql/mysql-systemd-start pre

除了使用以下 shell 程式碼對您的環境進行健全性檢查之外，這並沒有做太多事情：

sanity () {
  if [ ! -r /etc/mysql/my.cnf ]; then
    echo "MySQL configuration not found at /etc/mysql/my.cnf. Please create one."
    exit 1
  fi

  if [ ! -d /var/lib/mysql ] && [ ! -L /var/lib/mysql ]; then
    echo "MySQL data dir not found at /var/lib/mysql. Please create one."
    exit 1
  fi

  if [ ! -d /var/lib/mysql/mysql ] && [ ! -L /var/lib/mysql/mysql ]; then
    echo "MySQL system database not found. Please run mysql_install_db tool."
    exit 1
  fi
}

如果您直接透過 sudo 運行它，您應該會收到這些錯誤訊息之一，請按照其建議並重試，直到它起作用。

這不是隨機損壞，而是缺少文件，請檢查 root 使用者和任何可以 sudo 的使用者的 bash_history。