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MySQL數(shù)據(jù)庫(kù)被鎖定的問(wèn)題解決

更新時(shí)間：2024年10月28日 11:39:17 作者：不愿透露姓名的大鵬

本文主要介紹了MySQL數(shù)據(jù)庫(kù)被鎖定的問(wèn)題解決方法,包括通過(guò)刷新錯(cuò)誤連接、修改max_connection_errors的數(shù)量、執(zhí)行flush?host或者?mysqladmin?flush-hosts等方式進(jìn)行解決,感興趣的可以了解一下

問(wèn)題

ERROR 1129 (HY000): Host '192.168.10.10' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'

問(wèn)題驗(yàn)證

我們嘗試連接，用命令行也連接失敗。

[clog@MC-FSB ~]$mysql -uroot -h192.168.10.18 -p
Enter password: 
ERROR 1129 (HY000): Host '192.168.10.10' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'

查看日志

查看mysql數(shù)據(jù)庫(kù)的日志

tail -n 200 /var/log/mysqld.log

解決辦法

進(jìn)入數(shù)據(jù)庫(kù)進(jìn)行刷新錯(cuò)誤連接，并且查看最大數(shù)量為100，并改為1000

修改max_connection_errors的數(shù)量為1000（立即生效）

 set global max_connect_errors = 1000;

在my.cnf中[mysqld]下添加（重啟后不失效）

max_connect_errors = 1000

[admin@wmsweb log]$ mysql -uroot -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1853635
Server version: 5.7.25 MySQL Community Server (GPL)

Copyright (c) 2000, 2019, Oracle and/or its affiliates. All rights reserved.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> 
mysql> flush hosts;
Query OK, 0 rows affected (0.00 sec)

mysql> show global variables like '%max_connect_errors%';
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| max_connect_errors | 100   |
+--------------------+-------+
1 row in set (0.01 sec)

mysql> set global max_connect_errors=1000;
Query OK, 0 rows affected (0.00 sec)

mysql> show global variables like '%max_connect_errors%';
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| max_connect_errors | 1000  |
+--------------------+-------+
1 row in set (0.00 sec)

mysql>

再次通過(guò)客戶(hù)端連接成功

[clog@MC-FSB ~]$mysql -uroot -h192.168.10.18 -p
Enter password: 
ERROR 1129 (HY000): Host '192.168.10.10' is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts'
[clog@MC-FSB ~]$mysql -uroot -h192.168.10.18 -p
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1853636
Server version: 5.7.25 MySQL Community Server (GPL)

Copyright (c) 2000, 2021, Oracle and/or its affiliates.

Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql>

根本解決辦法

解決ERROR 1129 (HY000)的方法是執(zhí)行flush host或者 mysqladmin flush-hosts，其目的是為了清空host cache里的信息，那是不是說(shuō)不使用host cache就可以了？

host_cache_size的作用

缺點(diǎn)：當(dāng)有一個(gè)新的客戶(hù)端連接進(jìn)來(lái)時(shí)，MySQL Server都要建立一個(gè)新的記錄，如果DNS解析很慢，無(wú)疑會(huì)影響性能。如果被允許訪(fǎng)問(wèn)的主機(jī)很多，也會(huì)影響性能，這個(gè)與host_cache_size有關(guān)，這個(gè)參數(shù)是5.6.5引入的。5.6.8之前默認(rèn)是128,5.6.8之后默認(rèn)是-1,基于max_connections的值動(dòng)態(tài)調(diào)整。所以如果被允許訪(fǎng)問(wèn)的主機(jī)很多，基于LRU算法，先前建立的連接可能會(huì)被擠掉，這些主機(jī)重新進(jìn)來(lái)時(shí)，會(huì)再次進(jìn)行DNS查詢(xún)。

優(yōu)點(diǎn)：通常情況下，主機(jī)名是不變的，而IP是多變的。如果一個(gè)客戶(hù)端的IP經(jīng)常變化，那基于IP的授權(quán)將是一個(gè)繁瑣的過(guò)程。因?yàn)槟愫茈y確定IP什么時(shí)候變化。而基于主機(jī)名，只需一次授權(quán)。而且，基于host cache中的失敗信息，可在一定程度上阻止外界的暴力破解攻擊。

關(guān)于阻止外界的暴力破解攻擊，涉及到max_connect_errors參數(shù)，默認(rèn)為100，官方的解釋如下：

If more than this many successive connection requests from a host are interrupted without a successful connection, the server blocks that host from further connections.

如果某個(gè)客戶(hù)端的連接達(dá)到了max_connect_errors的限制，將被禁止訪(fǎng)問(wèn)，并提示以下錯(cuò)誤：

Host 'host_name' is blocked because of many connection errors.
Unblock with 'mysqladmin flush-hosts'
查看當(dāng)前的最大鏈接錯(cuò)誤數(shù).

mysql> show variables like 'max_connect_errors';
+--------------------+-------+
| Variable_name      | Value |
+--------------------+-------+
| max_connect_errors | 100   |
+--------------------+-------+
1 row in set (0.07 sec)

使host cache不生效(禁用 MySQL DNS 查找)的方式有如下兩種：

A、設(shè)置 host_cache_size 為0

mysql> set global host_cache_size=0;

B、配置skip-name-resolve

編輯mysql配置文件 my.cnf

vi /etc/my.cnf

在 [mysqld] 下面添加下面這一行

skip-name-resolve

??注意事項(xiàng)

但是需要注意??的是，如果這樣設(shè)置，你將沒(méi)辦法使用127.0.0.1進(jìn)行連接數(shù)據(jù)庫(kù)。

如果禁用了DNS 則 localhost 則不會(huì)解析成回環(huán)地址.登錄報(bào)錯(cuò).

[root@dbserver ~]# mysql -h127.0.0.1 -u root -p         
Enter password: 
ERROR 1045 (28000): Access denied for user 'root'@'127.0.0.1' (using password: YES)

如果該參數(shù)設(shè)置為OFF，則上述方式就會(huì)報(bào)錯(cuò)，通過(guò)報(bào)錯(cuò)信息可以看出，它直接將127.0.0.1轉(zhuǎn)化為localhost了。

[root@localhost ~]# mysql -uroot -h127.0.0.1 -p123456 -P3306
Warning: Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)

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