mysql+mycat实现读写分离

centos7
master	slave	mycat1.6	client
192.168.41.10	192.168.41.11	192.168.41.12	192.168.41.13

实验环境关闭自己的防火墙

配置所有主机hosts文件：

192.168.41.10 master
192.168.41.11 slave
192.168.41.12 mycat
192.168.41.13 client

1、master（41.10）：
vim /etc/my.cnf

[mysqld]
basedir = /usr/local/mysql
datadir = /usr/local/mysql/data
server_id =
socket = /usr/local/mysql/mysql.sock
log-error = /usr/local/mysql/data/mysqld.err
log-bin = mysql-bin

systemctl restart mysqld \重启服务读取配置文件参数
1)配置复制用户以及root用户权限

2、slave（41.11）
配置/etc/my.cnf配置文件

[mysqld]
basedir = /usr/local/mysql
datadir = /usr/local/mysql/data
server_id =
socket = /usr/local/mysql/mysql.sock
log-error = /usr/local/mysql/data/mysqld.err
relay-log = relay-log-bin
relay-log-index = slave-relay-bin.index

systemctl restart mysqld
mysql> change master to master_host='192.168.41.10',master_user='myslave',master_password='123.com',master_log_file='mysql-bin.000002',master_log_pos=1334;
mysql> start slave ;
mysql> show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
mysql> grant all on . to root@'%' identified by '123.com';
mysql> flush privileges;
回到master主机创建test库
mysql> create database test;
3、配置mycat（41.12）
1）部署mycat
wget http://dl.mycat.io/1.6-RELEASE/Mycat-server-1.6-RELEASE-20161028204710-linux.tar.gz
[root@192 ~]# tar zxf Mycat-server-1.6-RELEASE-20161028204710-linux.tar.gz -C /usr/local
2）加载环境变量
[root@192 ~]# vi /etc/profile
.....
export PATH=$PATH:/usr/local/java/bin
export JAVA_HOME=/usr/local/java
export MYCAT_HOME=/usr/local/mycat
export PATH=$PATH:/usr/local/mycat/bin
[root@192 ~]# source /etc/profile
3）配置serve.xml
[root@192 ~]# cd /usr/local/mycat/conf/
[root@192 conf]# vim server.xml

<user name="root">
<property name="password">.com</property>
<property name="schemas">test</property>

            !-- 表级 DML 权限设置 --!--
            privileges check="false"schema name="TESTDB" dml="" table name="tb01" dml=""/tabletable name="tb02" dml=""/table/schema/privileges--/useruser name="user"property name="password"user/propertyproperty name="schemas"test/propertyproperty name="readOnly"true/property/user</mycat:server>
4）配置schema.xml
[root@192 conf]# vim schema.xml
<?xml version="1.0"?>
<!DOCTYPE mycat:schema SYSTEM "schema.dtd">
<mycat:schema xmlns:mycat="http://io.mycat/">;

    <schema name="test" checkSQLschema="false" sqlMaxLimit="100" dataNode="dn1">
    </schema>

    <dataNode name="dn1" dataHost="host01" database="test" />

    <dataHost name="host01" maxCon="1000" minCon="10" balance="1"
                      writeType="0" dbType="mysql" dbDriver="native" switchType="1"  slaveThreshold="100">
            <heartbeat>show slave status</heartbeat>
            <writeHost host="hostM1" url="192.168.41.10:3306" user="root" password="123.com">
            <readHost host="hostS1" url="192.168.41.11:3306" user="root" password="123.com"/>
            </writeHost>
    </dataHost>
            </mycat:schema>

balance 属性负载均衡类型，目前的取值有 4 种：

balance="0", 不开启读写分离机制，所有读操作都发送到当前可用 的writeHost 上。 balance="1"，全部的 readHost 与 stand by writeHost 参与 select 语句的负载均衡，简单的说，当双主双从模式(M1 ->S1 ， M2->S2，并且 M1 与 M2 互为主备)，正常情况下， M2,S1,S2 都参与 select 语句的负载均衡。 balance="2"，所有读操作都随机的在 writeHost、 readhost 上分发。 balance="3"， 所有读请求随机的分发到 wiriterHost 对应的 readhost 执行,writerHost 不负担读压力，注意 balance=3 只在 1.4 及其以后版本有， 1.3 没有。

writeType 属性，负载均衡类型，目前的取值有 3 种：
writeType="0", 所有写操作发送到配置的第一个 writeHost，第一个挂了切到还生存的第二个writeHost，重新启动后已切换后的为准，切换记录在配置文件中:dnindex.properties . writeType="1"，所有写操作都随机的发送到配置的 writeHost。 writeType="2"，没实现。

switchType 属性
-1 表示不自动切换 1 默认值，自动切换 2 基于MySQL 主从同步的状态决定是否切换

5)启动mycat服务器
[root@192 logs]# mycat start
[root@192 logs]# tailf wrapper.log #观察启动日志，便于排错
[root@192 logs]# ss -anpt | grep java 
LISTEN 0 1 127.0.0.1:32000 : users:(("java",pid=40133,fd=4))
LISTEN 0 50 :::50632 ::: users:(("java",pid=40133,fd=51))
LISTEN 0 100 :::9066 ::: users:(("java",pid=40133,fd=69))
LISTEN 0 50 :::33782 ::: users:(("java",pid=40133,fd=53))
LISTEN 0 50 :::1984 ::: users:(("java",pid=40133,fd=52))
LISTEN 0 100 :::8066 :::* users:(("java",pid=40133,fd=73))

4、客户端（41.13）验证读写分离

①登录到连接端口

[root@ ~]# mysql -h 192.168.41.12 -P  -uroot -p123.com

mysql> show databases;
+----------+
| DATABASE |
+----------+
| test |
+----------+
 row in set (0.01 sec)

mysql> use test
Database changed
mysql> create table tb (id int);
Query OK,  rows affected (0.03 sec)

mysql> insert into tb values ();
Query OK,  row affected (0.05 sec)

mysql> select * from tb;
+------+
| id |
+------+
|  |
+------+
 row in set (0.02 sec)
②登录管理端口
[root@ ~]# mysql -P9066 -uroot -p123.com -h 192.168.41.12
mysql> show @@datasource ;
+----------+--------+-------+--------------+------+------+--------+------+------+---------+-----------+------------+
| DATANODE | NAME | TYPE | HOST | PORT | W/R | ACTIVE | IDLE | SIZE | EXECUTE | READ_LOAD | WRITE_LOAD |
+----------+--------+-------+--------------+------+------+--------+------+------+---------+-----------+------------+
| dn1 | hostM1 | mysql | 192.168.1.12 |  | W |  |  |  |  |  |  |
| dn1 | hostS1 | mysql | 192.168.1.10 |  | R |  |  |  |  |  |  |
+----------+--------+-------+--------------+------+------+--------+------+------+---------+-----------+------------+
从管理端口观察两主机负载变化，发现READ_LOAD在hostS1为2， WRITE_LOAD在hostM1为2，说明读写分离已经实现