MySQL读写分离

• 读写分离就是只在主服务器上写，只在从服务器上读
• 主数据库处理事务性查询，从而数据库处理select查询
• 数据库复制被用来把事务性查询导致的变更同步到集群中的从数据库
  
  案例实施
• 所有服务器关闭firewalld或者进行规则设置
• 搭建mysql主从复制环境
• Amoeba服务器环境安装
  
  配置amoeba读写分离，两个slave读负载均衡
• mysql1、mysql2和mysql3中执行以下操作开放权限给Amoeba
  
  修改amoeba配置文件
  /usr/local/amoeba/conf/amoeba.xml
  
  

• /usr/local/amoeba/conf/dbServers.xml
  
  
  
  启动Amoeba软件
  
  测试读负载均衡
  客户机访问数据库
  
  在数据库db_test中创建zang，并自动同步到2台从服务器
  
  两台从服务器数据库中关闭主从复制
  
  分别在mysql1、mysql2、mysql3的zang表中上插入不同的数据
  
  实操
  在amoeba服务器上安装amoeba需要先安装jdk依赖包

  cp jdk-6u14-linux-x64.bin /usr/local

  [root@amoeba abc]# cd /usr/local
  [root@amoeba local]# ls
  bin           etc    include                 lib    libexec  share  tomcat9
  boost_1_59_0  games  jdk-6u14-linux-x64.bin  lib64  sbin     src
  [root@amoeba local]# ./jdk-6u14-linux-x64.bin 
  //more，往下回车继续看，直到让你输入yes
  Do you agree to the above license terms? [yes or no]
  yes
  Press Enter to continue.....
  Done

  改个名字，便于管理

  [root@amoeba local]# mv jdk1.6.0_14/ /usr/local/jdk1.6
  [root@amoeba local]# ls
  bin           etc    include  jdk-6u14-linux-x64.bin  lib64    sbin   src
  boost_1_59_0  games  jdk1.6   lib                     libexec  share  tomcat9

  优化环境变量

  [root@amoeba local]# vim /etc/profile
  export JAVA_HOME=/usr/local/jdk1.6
  export CLASSPATH=$CLASSPATH:$JAVA_HOME/lib:$JAVA_HOME/jre/lib
  export PATH=$JAVA_HOME/lib:$JAVA_HOME/jre/bin/:$PATH:$HOME/bin
  export AMOEBA_HOME=/usr/local/amoeba
  export PATH=$PATH:$AMOEBA_HOME/bin
  [root@amoeba local]# source /etc/profile
  [root@amoeba local]# echo $PATH
  /usr/local/jdk1.6/lib:/usr/local/jdk1.6/jre/bin/:/usr/java/jdk1.8.0_201-amd64/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/root/bin:/usr/local/amoeba/bin

  依赖包安装完毕，接下来解压amoeba源码包

  [root@amoeba local]# mkdir /usr/local/amoeba
  [root@amoeba local]# cd /abc
  [root@amoeba abc]# tar zxvf amoeba-mysql-binary-2.2.0.tar.gz -C /usr/local/amoeba/
  [root@amoeba abc]# chmod -R 755 /usr/local/amoeba/
  [root@amoeba abc]# /usr/local/amoeba/bin/amoeba
  amoeba start|stop

  这个时候amoeba已经装好了，接下来绑定三台节点服务器，amoeba需要获得相应的权限的账号
  对所有的数据库进行配置

  mysql> grant all on *.* to test@‘192.168.247.%‘ identified by ‘123.com‘;
  Query OK, 0 rows affected (0.01 sec)

  回到amoeba服务器继续配置

  [root@amoeba abc]# cd /usr/local/amoeba/
  [root@amoeba amoeba]# vim conf/amoeba.xml 
  30                                         <property name="user">amoeba</property>
  //这里是数据库访问amoeba服务器时使用的账号
  31 
  32                                         <property name="password">123123</property>
  //这里是数据库访问amoeba服务器时使用账号时用的密码 
  115                 <property name="defaultPool">master</property>
  116 
  117                 <!-- -->        //取消下面的注释符号-->，改到这里
  118                 <property name="writePool">master</property>
  119                 <property name="readPool">slaves</property>
  120                 <property name="needParse">true</property>

  设置服务器文件/usr/local/amoeba/conf/dbServers.xml

  [root@amoeba amoeba]# cd conf/
  [root@amoeba conf]# ls
  access_list.conf  amoeba.xml    dbServers.xml  functionMap.xml  log4j.xml  ruleFunctionMap.xml
  amoeba.dtd        dbserver.dtd  function.dtd   log4j.dtd        rule.dtd   rule.xml
  [root@amoeba conf]# vim dbServers.xml 
  25                         <!-- mysql user -->
  26                         <property name="user">test</property>
  //这里是amoeba访问mysql时使用的账号
  27 
  28                         <!--  mysql password -->
  29                         <property name="password">123.com</property>
  //这里是amoeba访问mysql时使用账号的密码
  
  44         <dbServer name="master"  parent="abstractServer">
  45                 <factoryConfig>
  46                         <!-- mysql ip -->
  47                         <property name="ipAddress">192.168.247.160</property>
  48                 </factoryConfig>
  49         </dbServer>
  50 
  //上面6行是指定主服务器的地址
  51         <dbServer name="slave1"  parent="abstractServer">
  52                 <factoryConfig>
  53                         <!-- mysql ip -->
  54                         <property name="ipAddress">192.168.247.161</property>
  55                 </factoryConfig>
  56         </dbServer>
  57 
  //上面6行是指定从服务器1的地址
  58         <dbServer name="slave2"  parent="abstractServer">
  59                 <factoryConfig>
  60                         <!-- mysql ip -->
  61                         <property name="ipAddress">192.168.247.154</property>
  62                 </factoryConfig>
  63         </dbServer>
  64  
  //在原配置文件中，上面6行不存在，此处是由复制粘贴的得来，是指定从服务器2的地址       
  65         <dbServer name="slaves" virtual="true">
  //此处设置从服务器地址池slaves
  66                 <poolConfig class="com.meidusa.amoeba.server.MultipleServerPool">
  67                         <!-- Load balancing strategy: 1=ROUNDROBIN , 2=WEIGHTBASED , 3=HA-->
  68                         <property name="loadbalance">1</property>
  69 
  70                         <!-- Separated by commas,such as: server1,server2,server1 -->
  71                         <property name="poolNames">slave1,slave2</property>
  //此处填入从服务器名
  72                 </poolConfig>
  73         </dbServer>

  开启amoeba服务
  保存退出配置文件，开启amoeba服务，因为它内部有一个实时监控，持续性开启，所以需要在后台启动，而且无法再进行命令操作，若想再对它进行操作，可以重新开启一台远程，去连接
  验证

  [root@client ~]# systemctl stop firewall
  Failed to stop firewall.service: Unit firewall.service not loaded.
  [root@client ~]# setenforce 0
  [root@client ~]# yum install mysql -y
  //安装mysql去连接即可，client不需要安装数据库取存储数据
  [root@client ~]# mysql -u amoeba -p123123 -h 192.168.247.206 -P8066
  //连接amoeba服务器
  mysql: [Warning] Using a password on the command line interface can be insecure.
  Welcome to the MySQL monitor.  Commands end with ; or \g.
  Your MySQL connection id is 494299142
  Server version: 5.1.45-mysql-amoeba-proxy-2.2.0 Source distribution
  Copyright (c) 2000, 2017, 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> 

  此时先查看一下主服务器mysql中的数据库，此时school中是没有数据的

  mysql> show databases;
  +--------------------+
  | Database           |
  +--------------------+
  | information_schema |
  | mysql              |
  | performance_schema |
  | school             |
  | test               |
  +--------------------+
  5 rows in set (0.01 sec)
  mysql> show tables;
  ERROR 1046 (3D000): No database selected
  mysql> use school;
  Database changed
  mysql> show tables;
  Empty set (0.00 sec)

  回到链接到amoeba服务器的客户端client，创建school数据库

  mysql> create table info (id int(4)not null primary key,name varchar(10) not null,score decimal(4,1) not null);
  //创建一个新表
  Query OK, 0 rows affected (0.11 sec)
  mysql> desc info;
  +-------+--------------+------+-----+---------+-------+
  | Field | Type         | Null | Key | Default | Extra |
  +-------+--------------+------+-----+---------+-------+
  | id    | int(4)       | NO   | PRI | NULL    |       |
  | name  | varchar(10)  | NO   |     | NULL    |       |
  | score | decimal(4,1) | NO   |     | NULL    |       |
  +-------+--------------+------+-----+---------+-------+
  3 rows in set (0.02 sec)
  mysql> use school;
  Database changed
  mysql> show tables;
  +------------------+
  | Tables_in_school |
  +------------------+
  | info             |
  +------------------+
  1 row in set (0.00 sec)

  下面就开始做读写分离实验;

  mysql> stop slave;
  Query OK, 0 rows affected (0.01 sec)
  mysql> show slave status\G
  *************************** 1. row ***************************
             Slave_IO_State: 
                Master_Host: 192.168.247.160
                Master_User: myslave
                Master_Port: 3306
              Connect_Retry: 60
            Master_Log_File: master-bin.000001
        Read_Master_Log_Pos: 900
             Relay_Log_File: relay-log-bin.000002
              Relay_Log_Pos: 772
      Relay_Master_Log_File: master-bin.000001
  ‘             Slave_IO_Running: No
  ’            Slave_SQL_Running: No
      Seconds_Behind_Master: NULL
           Master_Server_Id: 11
                Master_UUID: e9a82741-3223-11ea-af25-000c29524d89
           Master_Info_File: /home/mysql/master.info
                  SQL_Delay: 0
        SQL_Remaining_Delay: NULL
         Master_Retry_Count: 86400
  1 row in set (0.00 sec)
  mysql> 

  此时在客户端写如数据,然后到主服务器查看，发现写入成功

  mysql> select * from info;
  +----+----------+-------+
  | id | name     | score |
  +----+----------+-------+
  |  1 | zhangsan |  88.0 |
  +----+----------+-------+
  1 row in set (0.00 sec)

  在从服务器在此查看

  mysql> select * from school.info;
  Empty set (0.00 sec)
  mysql> 

  由此可以发现读写已经分离，读从服务器，写主服务器
  此时在从服务器1内写入数据

  mysql>  insert into info (id,name,score) values (2,‘lisi‘,99);
  Query OK, 1 row affected (0.01 sec)

  此时在从服务器2内写入数据

  mysql>  insert into school.info (id,name,score) values (3,‘wangwu‘,60);
  Query OK, 1 row affected (0.01 sec)

  此时再到客户端去读取数据，可以发现实在轮流依次读取两台从服务器上的数据
  
  开启同步后在此检验
  

原文：https://blog.51cto.com/14557905/2465668