Docker MySQL 終端無法連線

問題描述

在使用Docer安裝MySQL容器後，在終端（Sequel Pro、Navcat）無法連線。

錯誤日誌

Connection failed!
Unable to connect to host 47.98.150.85, or the request timed out.
Be sure that the address is correct and that you have the necessary privileges, or try increasing the connection timeout (currently 10 seconds).
MySQL said: Authentication plugin 'caching_sha2_password' cannot be loaded: dlopen(/usr/local/lib/plugin/caching_sha2_password.so, 2): image not found
 

問題分析

出現該問題的原因是因為我使用的MySQL映象版本是8.0以上的。而MySQL 8.0預設的認證方式是：caching_sha2_password，之前版本的認證方式是：mysql_native_password。
這種情況下一些連線工具的jdbc連線尚未升級，所以會出現上述問題。
其次，在Java程式中，也將連線失敗。

解決方案

建立容器時，載入預設認證方式

在建立MySQL容器時，傳入預設的認證方式--default-authentication-plugin=mysql_native_password，完整命令如下：

docker run --name mysql -e MYSQL_ROOT_PASSWORD=123456 -d -p 3306:3306 mysql   --default-authentication-plugin=mysql_native_password
 

建立容器後，修改預設認證方式

這種方式在建立容器時，不需要傳入預設認證試--default-authentication-plugin=mysql_native_password。使用如下方式建立MySQL容器：

docker run --name mysql -e MYSQL_ROOT_PASSWORD=123456 -d -p 3306:3306 mysql

通過docker exec -it mysql bash進入容器，並登入MySQL資料庫：

[[email protected] ~]# docker exec -it mysql bash 
[email protected]
 
:/# mysql -uroot -p 
Enter password: 
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 8
Server version: 8.0.11 MySQL Community Server - GPL

Copyright (c) 2000, 2018, 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>

之後，切換至mysql資料庫，對原有資料庫資訊進行修改。
使用use mysql切換資料庫, 如下：

mysql> use mysql
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql>

檢視當前資料庫認證方式：

mysql> select user, host, plugin from user;
+------------------+-----------+-----------------------+
| user             | host      | plugin                |
+------------------+-----------+-----------------------+
| root             | %         | caching_sha2_password |
| mysql.infoschema | localhost | mysql_native_password |
| mysql.session    | localhost | mysql_native_password |
| mysql.sys        | localhost | mysql_native_password |
| root             | localhost | caching_sha2_password |
+------------------+-----------+-----------------------+
5 rows in set (0.00 sec)

mysql>

可以看出當前資料庫root使用者認證方式是caching_sha2_password。
修改認證方式：

mysql> alter user 'root'@'%' identified with mysql_native_password by '123456';
Query OK, 0 rows affected (0.06 sec)

mysql> select user, host, plugin from user;
+------------------+-----------+-----------------------+
| user             | host      | plugin                |
+------------------+-----------+-----------------------+
| root             | %         | mysql_native_password |
| mysql.infoschema | localhost | mysql_native_password |
| mysql.session    | localhost | mysql_native_password |
| mysql.sys        | localhost | mysql_native_password |
| root             | localhost | caching_sha2_password |
+------------------+-----------+-----------------------+
5 rows in set (0.00 sec)

mysql> 

至此，便可解決此問題。個人更推薦使用第一種方式。