mysql这几天运行的很好，但是今天突然无法启动了

Question

我有一个运行 WordPress 的服务器。
这几天都运行得很好，但是今天发现无法连接数据库。
于是我检查了服务器，发现mysql服务被关闭了。
然后我重新启动，但它只工作了一段时间，几秒钟后，它再次关闭。

这是mysql日志:

160508 10:07:36 [Warning] IP address '222.186.59.174' could not be resolved: Name or service not known
160508 14:08:14 [Warning] IP address '210.209.127.33' could not be resolved: Name or service not known
160508 23:08:15 [Warning] IP address '183.63.89.196' could not be resolved: Name or service not known
160509 16:08:02 [Warning] IP address '198.55.114.190' has been resolved to the host name '198.55.114.190.static.quadranet.com', which resembles IPv4-address itself.
160510  8:30:34 [Warning] IP address '222.186.134.25' could not be resolved: Name or service not known
160510 12:39:02 [Warning] IP address '118.193.255.253' could not be resolved: Name or service not known
160510 16:06:36 [Warning] IP address '118.193.218.65' could not be resolved: Name or service not known
160511  0:02:03 [Warning] IP address '116.255.183.230' could not be resolved: Name or service not known
160511 00:39:09 mysqld_safe Number of processes running now: 0
160511 00:39:09 mysqld_safe mysqld restarted
160511  0:39:10 [Note] /usr/libexec/mysqld (mysqld 5.5.47-MariaDB) starting as process 24298 ...
160511  0:39:42 InnoDB: The InnoDB memory heap is disabled
160511  0:39:42 InnoDB: Mutexes and rw_locks use GCC atomic builtins
160511  0:39:42 InnoDB: Compressed tables use zlib 1.2.7
160511  0:39:42 InnoDB: Using Linux native AIO
160511  0:39:42 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137756672 bytes) failed; errno 12
160511  0:39:42 InnoDB: Completed initialization of buffer pool
160511  0:39:42 InnoDB: Fatal error: cannot allocate memory for the buffer pool
160511  0:39:42 [ERROR] Plugin 'InnoDB' init function returned error.
160511  0:39:42 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
160511  0:39:42 [ERROR] mysqld: Out of memory (Needed 128917504 bytes)
160511  0:39:42 [ERROR] mysqld: Out of memory (Needed 96681984 bytes)
160511  0:39:42 [ERROR] mysqld: Out of memory (Needed 72499200 bytes)
160511 00:39:44 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
160511 17:11:08 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
160511 17:11:08 [Note] /usr/libexec/mysqld (mysqld 5.5.47-MariaDB) starting as process 24894 ...
160511 17:11:08 InnoDB: The InnoDB memory heap is disabled
160511 17:11:08 InnoDB: Mutexes and rw_locks use GCC atomic builtins
160511 17:11:08 InnoDB: Compressed tables use zlib 1.2.7
160511 17:11:08 InnoDB: Using Linux native AIO
160511 17:11:08 InnoDB: Initializing buffer pool, size = 128.0M
160511 17:11:08 InnoDB: Completed initialization of buffer pool
160511 17:11:08 InnoDB: highest supported file format is Barracuda.
InnoDB: The log sequence number in ibdata files does not match
InnoDB: the log sequence number in the ib_logfiles!
160511 17:11:08  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
160511 17:11:08  InnoDB: Waiting for the background threads to start
160511 17:11:09 Percona XtraDB (http://www.percona.com) 5.5.46-MariaDB-37.6 started; log sequence number 8239814
160511 17:11:09 [Note] Plugin 'FEEDBACK' is disabled.
160511 17:11:09 [Note] Server socket created on IP: '0.0.0.0'.
160511 17:11:09 [Note] Event Scheduler: Loaded 0 events
160511 17:11:09 [Note] /usr/libexec/mysqld: ready for connections.
Version: '5.5.47-MariaDB'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  MariaDB Server
160511 17:12:21 mysqld_safe Number of processes running now: 0
160511 17:12:21 mysqld_safe mysqld restarted
160511 17:12:21 [Note] /usr/libexec/mysqld (mysqld 5.5.47-MariaDB) starting as process 25104 ...
160511 17:12:21 InnoDB: The InnoDB memory heap is disabled
160511 17:12:21 InnoDB: Mutexes and rw_locks use GCC atomic builtins
160511 17:12:21 InnoDB: Compressed tables use zlib 1.2.7
160511 17:12:21 InnoDB: Using Linux native AIO
160511 17:12:21 InnoDB: Initializing buffer pool, size = 128.0M
InnoDB: mmap(137756672 bytes) failed; errno 12
160511 17:12:21 InnoDB: Completed initialization of buffer pool
160511 17:12:21 InnoDB: Fatal error: cannot allocate memory for the buffer pool
160511 17:12:21 [ERROR] Plugin 'InnoDB' init function returned error.
160511 17:12:21 [ERROR] Plugin 'InnoDB' registration as a STORAGE ENGINE failed.
160511 17:12:21 [ERROR] mysqld: Out of memory (Needed 128917504 bytes)
160511 17:12:21 [ERROR] mysqld: Out of memory (Needed 96681984 bytes)
160511 17:12:21 [ERROR] mysqld: Out of memory (Needed 72499200 bytes)
160511 17:12:21 [Note] Plugin 'FEEDBACK' is disabled.
160511 17:12:21 [ERROR] Unknown/unsupported storage engine: InnoDB
160511 17:12:21 [ERROR] Aborting

160511 17:12:21 [Note] /usr/libexec/mysqld: Shutdown complete

160511 17:12:21 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended

当我 ssh 到我的服务器时，我总是看到有很多失败的登录尝试，并且您可以看到日志中有很多 ip，是攻击者造成了这个问题还是我的服务器已被攻击？ ？
如果没有，我的服务器发生了什么？

Answer 1

请检查服务器上的内存分配。下面的错误日志行中出现此问题的真正原因:

160511 17:12:21 [ERROR] mysqld: Out of memory (Needed 128917504 bytes)
160511 17:12:21 [ERROR] mysqld: Out of memory (Needed 96681984 bytes)
160511 17:12:21 [ERROR] mysqld: Out of memory (Needed 72499200 bytes)