Mysql 5.7 无法创建 unix 套接字锁定文件

Posted 2023-02-24

【中文标题】Mysql 5.7 无法创建 unix 套接字锁定文件

【英文标题】：Mysql 5.7 Could not create unix socket lock file

【发布时间】：2017-08-14 06:55:25

【问题描述】：

我正在尝试在同一个 Ubuntu 16.10 32 位机器中创建多个 mysql 5.7 实例。我已将原始数据目录复制到新目录。为新实例创建了单独的日志文件夹（日志正在工作）。将新数据目录 /var/lib/mysql2 和日志目录 /var/log/mysql2/ 的所有者更改为 mysql:mysql。我已经删除了应用装甲。我只是在浏览了其他 SO 答案后才发布了这个问题……这些都没有解决多实例问题。

这是我的 my2.cnf：

[mysqld]
#
# * Basic Settings
#
user            = mysql
pid-file        = /var/run/mysqld/mysqld2.pid
socket          = /var/run/mysqld/mysqld2.sock
port            = 3307
basedir         = /usr
datadir         = /var/lib/mysql2
tmpdir          = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking
#
# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address            = 127.0.0.1
#
# * Fine Tuning
#
key_buffer_size         = 16M
max_allowed_packet      = 16M
thread_stack            = 192K
thread_cache_size       = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover-options  = BACKUP
#max_connections        = 100
#table_open_cache       = 64
#thread_concurrency     = 10
#
# * Query Cache Configuration
#
query_cache_limit       = 1M
query_cache_size        = 16M

[mysqld_safe]
socket          = /var/run/mysqld/mysqld2.sock
nice            = 0

如您所见，我已将端口分别更改为 3307 和其他端口。现在当我运行时（必须将 sudo 添加到 mysqld）：

sudo mysqld --defaults-file=/etc/mysql/my2.cnf &

我收到：

2017-03-22T08:31:21.684121Z 0 [Note] mysqld (mysqld 5.7.17-0ubuntu0.16.10.1) starting as process 13676 ...
2017-03-22T08:31:21.687115Z 0 [Note] InnoDB: PUNCH HOLE support available
2017-03-22T08:31:21.687131Z 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2017-03-22T08:31:21.687135Z 0 [Note] InnoDB: Uses event mutexes
2017-03-22T08:31:21.687140Z 0 [Note] InnoDB: GCC builtin __atomic_thread_fence() is used for memory barrier
2017-03-22T08:31:21.687143Z 0 [Note] InnoDB: Compressed tables use zlib 1.2.8
2017-03-22T08:31:21.687147Z 0 [Note] InnoDB: Using Linux native AIO
2017-03-22T08:31:21.687281Z 0 [Note] InnoDB: Number of pools: 1
2017-03-22T08:31:21.687344Z 0 [Note] InnoDB: Not using CPU crc32 instructions
2017-03-22T08:31:21.688116Z 0 [Note] InnoDB: Initializing buffer pool, total size = 128M, instances = 1, chunk size = 128M
2017-03-22T08:31:21.693801Z 0 [Note] InnoDB: Completed initialization of buffer pool
2017-03-22T08:31:21.694846Z 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the $
2017-03-22T08:31:21.708807Z 0 [Note] InnoDB: Highest supported file format is Barracuda.
2017-03-22T08:31:21.776053Z 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2017-03-22T08:31:21.776228Z 0 [Note] InnoDB: Setting file './ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2017-03-22T08:31:21.825266Z 0 [Note] InnoDB: File './ibtmp1' size is now 12 MB.
2017-03-22T08:31:21.826338Z 0 [Note] InnoDB: 96 redo rollback segment(s) found. 96 redo rollback segment(s) are active.
2017-03-22T08:31:21.826359Z 0 [Note] InnoDB: 32 non-redo rollback segment(s) are active.
2017-03-22T08:31:21.826695Z 0 [Note] InnoDB: Waiting for purge to start
2017-03-22T08:31:21.880277Z 0 [Note] InnoDB: 5.7.17 started; log sequence number 2535531
2017-03-22T08:31:21.881286Z 0 [Note] InnoDB: Loading buffer pool(s) from /var/lib/mysql2/ib_buffer_pool
2017-03-22T08:31:21.881581Z 0 [Note] Plugin 'FEDERATED' is disabled.
2017-03-22T08:31:21.887687Z 0 [Note] InnoDB: Buffer pool(s) load completed at 170322 14:01:21
2017-03-22T08:31:21.890330Z 0 [Warning] Failed to set up SSL because of the following SSL library error: SSL context is not usable without cer$
2017-03-22T08:31:21.890380Z 0 [Note] Server hostname (bind-address): '127.0.0.1'; port: 3307
2017-03-22T08:31:21.890407Z 0 [Note]   - '127.0.0.1' resolves to '127.0.0.1';
2017-03-22T08:31:21.890695Z 0 [Note] Server socket created on IP: '127.0.0.1'.
2017-03-22T08:31:21.890791Z 0 [ERROR] Could not create unix socket lock file /var/run/mysqld/mysqld2.sock.lock.
2017-03-22T08:31:21.890807Z 0 [ERROR] Unable to setup unix socket lock file.
2017-03-22T08:31:21.890819Z 0 [ERROR] Aborting

我错过了什么？

【问题讨论】：

mysql用户可以写信给/var/run/mysqld/吗？

是...该目录归mysql:mysql所有

...并且拥有rwx... 之类的权限，并且套接字文件不存在且权限或所有权错误？

原始 .sock 文件没有可执行权限（rw）。我也看不到文件夹中的mysql2.sock。

如果是我，我会在strace 下启动mysqld，以查看正在进行的调用以及返回的错误。这将产生大量输出，但由于 mysqld 正在关闭，因此不应无法管理。

【参考方案1】：

检查是否有锁文件

ls /var/run/mysqld/mysqld2.sock.lock

1。如果存在

1.1 检查哪个进程使用了​​锁文件

lsof /var/run/mysqld/mysqld2.sock.lock

1.1.1 如果没有进程使用锁文件

rm 锁定文件

rm /var/run/mysqld/mysqld2.sock.lock

然后启动mysql

1.1.2 如果有进程使用锁文件

将lock file and socket file更改为另一条路径

2。如果不存在

需要更多信息来检查正在发生的事情

strace -ff mysqld --defaults-file=/etc/mysql/my2.cnf

【参考方案2】：

对于那些使用 apparmor 的人，/etc/apparmor.d/usr.sbin.mysqld 中的以下权限允许 mysqld 创建和使用锁定文件。

/var/run/mysqld/mysqld2.pid rw,
/var/run/mysqld/mysqld2.sock rw,
/var/run/mysqld/mysqld2.sock.lock rw,

然后以 root 身份运行以下命令以重新加载配置文件。

apparmor_parser -r /etc/apparmor.d/usr.sbin.mysqld

由于某种原因，我在没有rw 对所有这三个文件的权限的情况下得到了 OP 的错误。