从本章开始，我们来实战如何在Docker下快速搭建主从同步的MySQL环境，《Docker下MySQL主从三部曲》由以下三章组成：
- 本章的内容，以最快的速度搭建和体验一主二从的MySQL主从环境；
- 细说第一章中的环境背后的技术细节，主要是如何制作MySQL主从的镜像；
- 验证bin log参数值对主从同步的影响；
文章目标
写《Docker下MySQL主从三部曲》的目标，是想利用docker制作一套MySQL主从的镜像文件，将搭建MySQL主从同步环境的步骤简化到极致；
设置主从同步的基本操作
实战前推荐阅读《Docker下手工配置MySQL主从》，里面介绍了手动设置MySQL主从同步的每个步骤，可以作为本章的准备工作；
实战环境
- 当前电脑的操作系统是Ubuntu 16.04.3 LTS；
- docker的版本信息如下：
Client:
Version: 17.03.2-ce
API version: 1.27
Go version: go1.7.5
Git commit: f5ec1e2
Built: Tue Jun 27 03:35:14 2017
OS/Arch: linux/amd64
Server:
Version: 17.03.2-ce
API version: 1.27 (minimum version 1.12)
Go version: go1.7.5
Git commit: f5ec1e2
Built: Tue Jun 27 03:35:14 2017
OS/Arch: linux/amd64
Experimental: false- docker-compose版本信息如下：
docker-compose version 1.18.0, build 8dd22a9
docker-py version: 2.7.0
CPython version: 2.7.12
OpenSSL version: OpenSSL 1.0.2g 1 Mar 2016开始极速体验
- 创建docker-compose.yml文件，内容如下：
version: '2'
services:
master:
image: bolingcavalry/mysql-master:0.0.1
environment:
MYSQL_ROOT_PASSWORD: 888888
MYSQL_REPLICATION_USER: rep
MYSQL_REPLICATION_PASSWORD: 888888
volumes:
- ./master:/etc/mysql/extend.conf.d
restart: always
slave0:
image: bolingcavalry/mysql-slave:0.0.1
depends_on:
- master
links:
- master:masterhost
environment:
MYSQL_ROOT_PASSWORD: 888888
MYSQL_MASTER_SERVICE_HOST: masterhost
MYSQL_REPLICATION_USER: rep
MYSQL_REPLICATION_PASSWORD: 888888
volumes:
- ./slave0:/etc/mysql/extend.conf.d
restart: always
slave1:
image: bolingcavalry/mysql-slave:0.0.1
depends_on:
- master
links:
- master:masterhost
environment:
MYSQL_ROOT_PASSWORD: 888888
MYSQL_MASTER_SERVICE_HOST: masterhost
MYSQL_REPLICATION_USER: rep
MYSQL_REPLICATION_PASSWORD: 888888
volumes:
- ./slave1:/etc/mysql/extend.conf.d
restart: always- 在docker-compose.yml文件平级的目录创建三个文件夹，名字分别是：master、slave0、slave1；
- 在master文件夹下创建文件master.cnf，内容如下：
[mysqld]
log-bin=mysql-bin
server-id=1- 在slave0文件夹下创建文件slave0.cnf，内容如下：
[mysqld]
server-id=2- 在slave1文件夹下创建文件slave1.cnf，内容如下：
[mysqld]
server-id=3- 完成上述操作后，文件和文件夹的情况如下所示：
├── docker-compose.yml
├── master
│ └── master.cnf
├── slave0
│ └── slave0.cnf
└── slave1
└── slave1.cnf
3 directories, 4 files- 在docker-compos.yml所在目录执行命令docker-compose up -d，立即开始下载镜像然后启动容器，此过程略耗时，请耐心等待，如下：
Creating network "dockercompose_default" with the default driver
Pulling master (bolingcavalry/mysql-master:0.0.1)...
0.0.1: Pulling from bolingcavalry/mysql-master
...
fb86dffe37e3: Pull complete
Digest: sha256:1d66de68d7855ff6447bf0896de7e04db91f6d015faa3fa6c96f76225a592c9f
Status: Downloaded newer image for bolingcavalry/mysql-master:0.0.1
Pulling slave1 (bolingcavalry/mysql-slave:0.0.1)...
0.0.1: Pulling from bolingcavalry/mysql-slave
...
353ccce48dc1: Pull complete
86282305ffa7: Pull complete
6f57fa284461: Pull complete
Creating dockercompose_master_1 ... done
Status: Downloaded newer image for bolingcavalry/mysql-slave:0.0.1
Creating dockercompose_master_1 ...
Creating dockercompose_slave1_1 ... done
Creating dockercompose_slave0_1 ... done- 执行命令docker ps，看到三个容器的信息如下：
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
e54cdfd72e9e bolingcavalry/mysql-slave:0.0.1 "docker-entrypoint..." 2 minutes ago Up 2 minutes 3306/tcp dockercompose_slave1_1
1d2cc65d23af bolingcavalry/mysql-slave:0.0.1 "docker-entrypoint..." 2 minutes ago Up 2 minutes 3306/tcp dockercompose_slave0_1
17025c108f2b bolingcavalry/mysql-master:0.0.1 "docker-entrypoint..." 2 minutes ago Up 2 minutes 3306/tcp dockercompose_master_1为了方便后面的操作，用表格将三个容器信息列出：
身份 | 容器ID |
主库 | 17025c108f2b |
第一从库 | 1d2cc65d23af |
第二从库 | e54cdfd72e9e |
至此，一主二从的MySQL环境就搭建好了，接下来开始验证主从同步吧；
验证主从同步
- 执行docker exec -it 17025c108f2b /bin/bash进入主库容器；
- 进入主库容器后，执行命令mysql -uroot -p进入MySQL命令行，按照提示输入密码"888888"，成功进入；
- 在MySQL命令行执行show master status，看到主库同步状态如下：
mysql> show master status;
+------------------+----------+--------------+------------------+-------------------+
| File | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
+------------------+----------+--------------+------------------+-------------------+
| mysql-bin.000003 | 154 | | | |
+------------------+----------+--------------+------------------+-------------------+
1 row in set (0.00 sec)- 在MySQL命令行执行以下四个命令，完成创建数据库、选择数据库、创建表、新增记录等操作：
create database test001;
use test001;
CREATE TABLE `test_table` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(100) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into test_table(name) values ('jerry');- 退出主库容器，执行docker exec -it 1d2cc65d23af /bin/bash进入第一从库容器；
- 进入第一从库容器后，执行命令mysql -uroot -p进入MySQL命令行，按照提示输入密码"888888"，成功进入；
- 在MySQL命令行执行show slave status\G，看到第一从库同步状态如下：
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: masterhost
Master_User: rep
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 905
Relay_Log_File: 1d2cc65d23af-relay-bin.000005
Relay_Log_Pos: 1118
Relay_Master_Log_File: mysql-bin.000003
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB:
Replicate_Ignore_DB:
Replicate_Do_Table:
Replicate_Ignore_Table:
Replicate_Wild_Do_Table:
Replicate_Wild_Ignore_Table:
Last_Errno: 0
Last_Error:
Skip_Counter: 0
Exec_Master_Log_Pos: 905
Relay_Log_Space: 3040769
Until_Condition: None
Until_Log_File:
Until_Log_Pos: 0
Master_SSL_Allowed: No
Master_SSL_CA_File:
Master_SSL_CA_Path:
Master_SSL_Cert:
Master_SSL_Cipher:
Master_SSL_Key:
Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
Last_IO_Errno: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
Replicate_Ignore_Server_Ids:
Master_Server_Id: 1
Master_UUID: 383054c7-34ae-11e8-8ac5-0242ac120002
Master_Info_File: /var/lib/mysql/master.info
SQL_Delay: 0
SQL_Remaining_Delay: NULL
Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates
Master_Retry_Count: 86400
Master_Bind:
Last_IO_Error_Timestamp:
Last_SQL_Error_Timestamp:
Master_SSL_Crl:
Master_SSL_Crlpath:
Retrieved_Gtid_Set:
Executed_Gtid_Set:
Auto_Position: 0
Replicate_Rewrite_DB:
Channel_Name:
Master_TLS_Version:
1 row in set (0.00 sec)- 在MySQL命令行执行use test001;选中数据库；
- 在MySQL命令行执行select * from test_table;查询数据，结果如下：
mysql> use test001;
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> select * from test_table;
+----+-------+
| id | name |
+----+-------+
| 1 | jerry |
+----+-------+
1 row in set (0.00 sec)可以看到主库的数据已经成功同步过来了，您可以继续检查第二从库的同步状况；
至此，极速体验MySQL主从同步的操作就结束了，比起《Docker下手工配置MySQL主从》的操作步骤，本章要简单很多，接下来的章节我们一起细看简单的背后所隐藏的技术；
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