Ubuntu 20.04 - 停止 MySQL。现在它无法启动（错误13，权限被拒绝）

Question

在 Ubuntu 20.04 上运行 DigitalOcean LAMP Stack (1GB VPS) 时，我在上传媒体文件时在 Wordpress 中遇到间歇性的“建立数据库连接错误”错误。这引发了以下 Apache 错误：

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WordPress database error MySQL server has gone away for query...

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发生此问题时，MySQL 日志重复打印以下内容，此后不再打印其他内容：

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    2020-12-19T12:14:43.708558Z 0 [System] [MY-013602] [Server] Channel mysql_main configured to support TLS. Encrypted connections are now supported for this channel.\n    2020-12-19T12:14:43.992793Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: \'8.0.22-0ubuntu0.20.04.3\'  socket: \'/var/run/mysqld/mysqld.sock\'  port: 3306  (Ubuntu).\n    2020-12-19T12:14:59.498001Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.22-0ubuntu0.20.04.3) starting as process 190645\n    2020-12-19T12:14:59.512933Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.\n    2020-12-19T12:15:00.093514Z 1 [System] [MY-013577] [InnoDB] InnoDB initialization has ended.\n    2020-12-19T12:15:00.448326Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Bind-address: \'127.0.0.1\' port: 33060, socket: /var/run/mysqld/mysqlx.sock\n    2020-12-19T12:15:00.524531Z 0 [System] [MY-010229] [Server] Starting XA crash recovery...\n    2020-12-19T12:15:00.543848Z 0 [System] [MY-010232] [Server] XA crash recovery finished.\n    2020-12-19T12:15:00.652394Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed.\n

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我尝试了此修复：WordPress 数据库错误 MySQL 服务器已消失进行查询

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网站仍然显示错误，所以我想我应该重新启动 MySQL，但它不会重新启动。

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有了sudo service MySQL start，我得到

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

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运行第一个命令：

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\xe2\x97\x8f mysql.service - MySQL Community Server\n Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled)\n Active: failed (Result: exit-code) since Sat 2020-12-19 12:45:50 UTC; 1min 3s ago\nProcess: 192068 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS)\nProcess: 192076 ExecStart=/usr/sbin/mysqld (code=exited, status=1/FAILURE)\nMain PID: 192076 (code=exited, status=1/FAILURE)\n Status: "Server startup in progress"\n  Error: 13 (Permission denied)\n

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运行第二个命令

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 Hint: You are currently not seeing messages from other users and the system.\n  Users in groups \'adm\', \'systemd-journal\' can see all messages.\n  Pass -q to turn off this notice.\n -- Defined-By: systems\n -- Support: http://www.ubuntu.com/support\n --\n -- A start job for unit UNIT has finished successfully.\n --\n -- The job identifier is 8.\n Dec 19 12:13:48 server systemd[189372]: Listening on REST API socket for snapd user session agent.\n -- Subject: A start job for unit UNIT has finished successfully\n -- Defined-By: systems\n -- Support: http://www.ubuntu.com/support\n --\n -- A start job for unit UNIT has finished successfully.\n --\n -- The job identifier is 11.\n Dec 19 12:13:48 server systemd[189372]: Listening on D-Bus User Message Bus Socket.\n -- Subject: A start job for unit UNIT has finished successfully\n -- Defined-By: systems\n -- Support: http://www.ubuntu.com/support\n --\n -- A start job for unit UNIT has finished successfully.\n --\n -- The job identifier is 9.\n Dec 19 12:13:48 server systemd[189372]: Reached target Sockets.\n -- Subject: A start job for unit UNIT has finished successfully\n -- Defined-By: systems\n -- Support: http://www.ubuntu.com/support\n --\n -- A start job for unit UNIT has finished successfully.\n --\n -- The job identifier is 5.\n Dec 19 12:13:48 server systemd[189372]: Reached target Basic System.\n -- Subject: A start job for unit UNIT has finished successfully\n -- Defined-By: systems\n -- Support: http://www.ubuntu.com/support\n --\n -- A start job for unit UNIT has finished successfully.\n --\n -- The job identifier is 2.\n Dec 19 12:13:48 server systemd[189372]: Reached target Main User Target.\n -- Subject: A start job for unit UNIT has finished successfully\n -- Defined-By: systems\n -- Support: http://www.ubuntu.com/support\n --\n -- A start job for unit UNIT has finished successfully.\n --\n -- The job identifier is 1.\n Dec 19 12:13:48 server systemd[189372]: Startup finished in 168ms.\n -- Subject: User manager start-up is now complete\n -- Defined-By: systems\n -- Support: http://www.ubuntu.com/support\n --\n -- The user manager instance for user 1000 has been started. All services queued\n -- for starting have been started. Note that other services might still be starting\n -- up or be started at any later time.\n --\n -- Startup of the manager took 168965 microseconds.\n Dec 19 12:15:07 server sudo[190726]: pam_unix(sudo:auth): Couldn\'t open /etc/securetty: No such file or directory\n Dec 19 12:15:09 server sudo[190726]: pam_unix(sudo:auth): Couldn\'t open /etc/securetty: No such file or directory\n Dec 19 12:30:17 server sudo[191518]: pam_unix(sudo:auth): Couldn\'t open /etc/securetty: No such file or directory\n Dec 19 12:30:19 server sudo[191518]: pam_unix(sudo:auth): Couldn\'t open /etc/securetty: No such file or directory\n Dec 19 12:32:25 server sudo[191686]: pam_unix(sudo:auth): Couldn\'t open /etc/securetty: No such file or directory\n Dec 19 12:32:27 server sudo[191686]: pam_unix(sudo:auth): Couldn\'t open /etc/securetty: No such file or directory\n

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第一个错误导致我这样做： https: //askubuntu.com/questions/1228827/mysql-error-13-permission-denied

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然而MySQL已经拥有/var/lib/mysql。/usr/sbin/mysqld 的所有者是 root。这与 MySQL 运行良好的另一台服务器上的情况相同。我真的应该改变这个吗？

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Answer 1

问题是我已授予我的用户/var/log/mysql读取文件的所有权。sudo chown mysql:mysql -R /var/log/mysql允许我启动mysql。