.. _mysql_exit_error: ======================= MySQL服务退出错误排查 ======================= mysql exited with error code ============================= 个人搭建的基于 :ref:`ghost_cms` 使用了 MySQL 作为数据存储，在VPS虚拟机重启后，Ghost CMS无法使用后端MySQL。检查数据库状态:: systemctl start mysql 提示错误:: Job for mysql.service failed because the control process exited with error code. See "systemctl status mysql.service" and "journalctl -xe" for details. mysql服务状态 ---------------- - 检查服务状态输出:: systemctl status mysql.service 显示:: ● mysql.service - MySQL Community Server Loaded: loaded (/lib/systemd/system/mysql.service; enabled; vendor preset: enabled) Active: failed (Result: exit-code) since Tue 2021-08-10 15:43:35 CST; 23min ago Process: 16817 ExecStart=/usr/sbin/mysqld --daemonize --pid-file=/run/mysqld/mysqld.pid (code=exited, status=1/FAILURE) Process: 16796 ExecStartPre=/usr/share/mysql/mysql-systemd-start pre (code=exited, status=0/SUCCESS) Main PID: 612 (code=killed, signal=KILL) Aug 10 15:43:35 freedom systemd[1]: mysql.service: Failed with result 'exit-code'. Aug 10 15:43:35 freedom systemd[1]: Failed to start MySQL Community Server. Aug 10 15:43:35 freedom systemd[1]: mysql.service: Service hold-off time over, scheduling restart. Aug 10 15:43:35 freedom systemd[1]: mysql.service: Scheduled restart job, restart counter is at 5. Aug 10 15:43:35 freedom systemd[1]: Stopped MySQL Community Server. Aug 10 15:43:35 freedom systemd[1]: mysql.service: Start request repeated too quickly. Aug 10 15:43:35 freedom systemd[1]: mysql.service: Failed with result 'exit-code'. Aug 10 15:43:35 freedom systemd[1]: Failed to start MySQL Community Server. - 通过 ``journalctl -xe`` 检查可以看到:: Aug 11 20:51:59 freedom systemd[1]: Starting MySQL Community Server... -- Subject: Unit mysql.service has begun start-up -- Defined-By: systemd -- Support: http://www.ubuntu.com/support -- -- Unit mysql.service has begun starting up. Aug 11 20:52:00 freedom mysqld[26240]: Initialization of mysqld failed: 0 Aug 11 20:52:00 freedom systemd[1]: mysql.service: Control process exited, code=exited status=1 Aug 11 20:52:00 freedom systemd[1]: mysql.service: Failed with result 'exit-code'. Aug 11 20:52:00 freedom systemd[1]: Failed to start MySQL Community Server. - 检查 ``/var/log/mysql/error.log`` 日志可以看到:: 2021-08-11T12:52:00.377011Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). 2021-08-11T12:52:00.392173Z 0 [Note] /usr/sbin/mysqld (mysqld 5.7.34-0ubuntu0.18.04.1) starting as process 26242 ... 2021-08-11T12:52:00.438647Z 0 [Note] InnoDB: PUNCH HOLE support available 2021-08-11T12:52:00.438697Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins 2021-08-11T12:52:00.438703Z 0 [Note] InnoDB: Uses event mutexes 2021-08-11T12:52:00.438707Z 0 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier 2021-08-11T12:52:00.438711Z 0 [Note] InnoDB: Compressed tables use zlib 1.2.11 2021-08-11T12:52:00.438723Z 0 [Note] InnoDB: Using Linux native AIO 2021-08-11T12:52:00.440910Z 0 [Note] InnoDB: Number of pools: 1 2021-08-11T12:52:00.445361Z 0 [Note] InnoDB: Using CPU crc32 instructions 2021-08-11T12:52:00.454508Z 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M 2021-08-11T12:52:00.456527Z 0 [ERROR] InnoDB: mmap(137428992 bytes) failed; errno 12 2021-08-11T12:52:00.456550Z 0 [ERROR] InnoDB: Cannot allocate memory for the buffer pool 2021-08-11T12:52:00.456560Z 0 [ERROR] InnoDB: Plugin initialization aborted with error Generic error 2021-08-11T12:52:00.456570Z 0 [ERROR] Plugin 'InnoDB' init function returned error. 2021-08-11T12:52:00.456577Z 0 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed. 2021-08-11T12:52:00.456584Z 0 [ERROR] Failed to initialize builtin plugins. 2021-08-11T12:52:00.456832Z 0 [ERROR] Aborting 2021-08-11T12:52:00.457348Z 0 [Note] Binlog end 2021-08-11T12:52:00.468226Z 0 [Note] Shutting down plugin 'CSV' 2021-08-11T12:52:00.468937Z 0 [Note] /usr/sbin/mysqld: Shutdown complete 2021-08-11T12:52:01.095959Z 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details). 从mysql日志来看，启动时 InnoDB初始化失败，原因是不能为缓冲池分配内存( ``InnoDB: Cannot allocate memory for the buffer pool`` ) - 观察内存使用:: # free total used free shared buff/cache available Mem: 492560 290200 24268 764 178092 189576 Swap: 0 0 0 - 之前内存应该是足够使用的，部署初始时资源足够，所以我考虑重启一次系统，观察情况 重启系统之后，果然能够正常启动mysql和ghost cms，初始内存使用状况如下:: top - 21:23:56 up 8 min, 1 user, load average: 0.00, 0.03, 0.03 Tasks: 91 total, 1 running, 53 sleeping, 0 stopped, 0 zombie %Cpu(s): 0.0 us, 0.0 sy, 0.0 ni,100.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem : 492560 total, 9136 free, 400224 used, 83200 buff/cache KiB Swap: 0 total, 0 free, 0 used. 79584 avail Mem PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 611 mysql 20 0 1164088 188936 7160 S 0.0 38.4 0:00.59 mysqld 864 ghost 20 0 893936 104132 18964 S 0.0 21.1 0:07.43 node 519 ghost 20 0 632608 25616 7584 S 0.0 5.2 0:01.32 ghost run 748 proxy 20 0 155540 18752 2672 S 0.0 3.8 0:00.08 squid 575 root 20 0 187548 10464 2564 S 0.0 2.1 0:00.13 unattended-upgr 532 root 20 0 170736 10084 2324 S 0.0 2.0 0:00.16 networkd-dispat 608 www-data 20 0 158748 6796 4712 S 0.0 1.4 0:00.04 nginx 402 root 19 -1 78328 5760 5152 S 0.0 1.2 0:00.14 systemd-journal 1040 huatai 20 0 24692 5104 3516 S 0.0 1.0 0:00.02 bash 1 root 20 0 225020 4560 2512 S 0.0 0.9 0:02.29 systemd 923 root 20 0 112160 4520 3488 S 0.0 0.9 0:00.01 sshd 1054 huatai 20 0 46104 3892 3296 R 0.0 0.8 0:00.39 top 内存不足 =========== 虽然重启一次后暂时满足了暂时需求，但是发现无法对系统做进一步维护，例如无法执行 ``apt upgrade`` (出现OOM)，所以最终还是采用升级VPS，将原先512M内存升级成1G，每月多支付 1.5 $。