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Docker 修改MySQL配置

作者：YoungJ

前言：大部分程序员在刚使用docker时，按照教程迅速的就装完了mysql，在使用的过程中出现各种问题：比如中文乱码、com.mysql.jdbc.PacketTooBigException: Packet for query is too large (1053 > 1024).等等，最简单的方式通过sql去设置，但每次重启又还原了，那么本文就是通过docker下MySQL的配置去解决该问题。

从安装说起，获取镜像
```
docker pull mysql:5.7.18
```
查看镜像
```
docker images
```

运行docker容器

docker run -d -p 3306:3306 --name mymysql -e MYSQL_ROOT_PASSWORD=123456 mysql:5.7.18

(* 这里没有设置挂载外部的配置)

查看容器是否启动成功
```
docker ps
```
进入容器
```
docker exec -it 1383f2e49cb7 /bin/bash
```
查看配置
```
more /etc/mysql/mysql.conf.d/mysqld.cnf
```
（* 如果你执行到这步提示没有该文件，别着急，往下看）

编辑配置

第一种方式：将配置从容器中copy到宿主机（之前文章讲到过，可以去看下，如果没有该文件，那这一步省略，稍后直接将我写好的配置放到容器中就好）

docker cp mysql:/etc/mysql/mysql.conf.d/mysqld.cnf /root/mysqld.cnf

mysqld.cnf脚本如下：

# Copyright (c) 2014, 2016, Oracle and/or its affiliates. All rights reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

#
# The MySQL Server configuration file.
#
# For explanations see
# http://dev.mysql.com/doc/mysql/en/server-system-variables.html

[mysqld]
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
#log-error = /var/log/mysql/error.log
# By default we only accept connections from localhost
#bind-address = 127.0.0.1
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
character_set_server=utf8
init_connect='SET NAMES utf8'
max_allowed_packet = 20M

[mysql]
default-character-set = utf8

[mysql.server]
default-character-set = utf8

[mysqld_safe]
default-character-set = utf8

[client]
default-character-set = utf8

将修改后的配置copy到容器

docker cp /root/mysqld.cnf mymysql:/etc/mysql/mysql.conf.d/

(* mymysql是你容器的name,不清楚的可以通过docker ps看到)

另一种方式，直接编辑
在使用docker容器时，有时候里边没有安装vim，敲vim命令时提示说：vim: command not found，这个时候就需要安装vim，可是当你敲apt-get install vim命令时，提示：
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Unable to locate package vim
这时候需要敲：
```
apt-get update
```
这个命令的作用是：同步 /etc/apt/sources.list 和 /etc/apt/sources.list.d 中列出的源的索引，这样才能获取到最新的软件包。
等更新完毕以后再敲命令：
```
apt-get install vim
```
```
vim /etc/mysql/mysql.conf.d/mysqld.cnf
```