Amoeba+Mysql实现数据库读写分离

一、Amoeba 是什么

Amoeba(变形虫)项目，专注 分布式数据库 proxy 开发。座落与Client、DB Server(s)之间。对客户端透明。具有负载均衡、高可用性、sql过滤、读写分离、可路由相关的query到目标数据库、可并发请求多台数据库合并结果。

主要解决：

• 降低 数据切分带来的复杂多数据库结构

• 提供切分规则并降低 数据切分规则 给应用带来的影响

• 降低db 与客户端的连接数

• 读写分离

二、为什么要用Amoeba

目前要实现mysql的主从读写分离，主要有以下几种方案：

1、  通过程序实现，网上很多现成的代码，比较复杂，如果添加从服务器要更改多台服务器的代码。

2、  通过mysql-proxy来实现，由于mysql-proxy的主从读写分离是通过lua脚本来实现，目前lua的脚本的开发跟不上节奏，而写没有完美的现成的脚本，因此导致用于生产环境的话风险比较大，据网上很多人说mysql-proxy的性能不高。

3、  自己开发接口实现，这种方案门槛高，开发成本高，不是一般的小公司能承担得起。

4、  利用阿里巴巴的开源项目Amoeba来实现，具有负载均衡、高可用性、sql过滤、读写分离、可路由相关的query到目标数据库，并且安装配置非常简单。国产的开源软件，应该支持，目前正在使用，不发表太多结论，一切等测试完再发表结论吧，哈哈！

三、Amoeba的安装

先介绍下部署环境：

amoeba:192.168.2.203

masterDB：192.168.2.204

slaveDB：192.168.2.205

以上系统全为centos6.8

Amoeba框架是居于JDK1.5开发的，采用了JDK1.5的特性，所以还需要安装java环境，建议使用javaSE1.5以上的JDK版本

1、安装java环境

先去官网下载：http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html

安装

[root@bogon src]# rpm -ivh jdk-8u111-linux-x64.rpm
Preparing...                ########################################### [%]
   :jdk1..0_111           ########################################### [%]
Unpacking JAR files...
    tools.jar...
    plugin.jar...
    javaws.jar...
    deploy.jar...
    rt.jar...
    jsse.jar...
    charsets.jar...
    localedata.jar...

然后设置java环境变量

[root@bogon src]# vim /etc/profile

#set java environment
JAVA_HOME=/usr/java/jdk1..0_111
JRE_HOME=/usr/java/jdk1..0_111/jre
CLASS_PATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
PATH=$PATH:$JAVA_HOME/bin:$JRE_HOME/bin
export JAVA_HOME JRE_HOME CLASS_PATH PATH
[root@bogon amoeba]# source /etc/profile

测试是否安装成功

[root@bogon src]# java -version
java version "1.8.0_111"
Java(TM) SE Runtime Environment (build 1.8.0_111-b14)
Java HotSpot(TM) -Bit Server VM (build 25.111-b14, mixed mode)

2、安装Amoeba

可以从https://sourceforge.net/projects/amoeba/下载最新版本的Amoeba，我这里下载的是amoeba-mysql-3.0.5-RC-distribution.zip。Amoeba安装非常简单，直接解压即可使用，这里将Amoeba解压到/usr/local/amoeba目录下，这样就安装完成了

[root@bogon amoeba]# pwd
/usr/local/amoeba

[root@bogon amoeba]# ll
  总用量 20
  drwxrwxrwx. 2 root root 4096 7月 5 2013 benchmark
  drwxrwxrwx. 2 root root 4096 7月 5 2013 bin
  drwxrwxrwx. 2 root root 4096 7月 5 2013 conf
  -rwxrwxrwx. 1 root root 728 7月 5 2013 jvm.properties
  drwxrwxrwx. 2 root root 4096 7月 5 2013 lib

3、配置Amoeba

Amoeba的配置文件在本环境下位于/usr/local/amoeba/conf目录下。配置文件比较多，但是仅仅使用读写分离功能，只需配置两个文件即可，分别是dbServers.xml和amoeba.xml，如果需要配置ip访问控制，还需要修改access_list.conf文件，下面首先介绍dbServers.xml

[root@bogon amoeba]# cat conf/dbServers.xml
<?xml version="1.0" encoding="gbk"?>

<!DOCTYPE amoeba:dbServers SYSTEM "dbserver.dtd">
<amoeba:dbServers xmlns:amoeba="http://amoeba.meidusa.com/">

        <!--
            Each dbServer needs to be configured into a Pool,
            If you need to configure multiple dbServer with load balancing that can be simplified by the following configuration:
             add attribute with name virtual = "true" in dbServer, but the configuration does not allow the element with name factoryConfig
             such as 'multiPool' dbServer
        -->

    <dbServer name="abstractServer" abstractive="true">
        <factoryConfig class="com.meidusa.amoeba.mysql.net.MysqlServerConnectionFactory">
            <property name="connectionManager">${defaultManager}</property>
            <property name="sendBufferSize"></property>
            <property name="receiveBufferSize"></property>

            <!-- mysql port -->
            <property name="port"></property>　　#设置Amoeba要连接的mysql数据库的端口，默认是3306

            <!-- mysql schema -->
            <property name="schema">testdb</property>　　#设置缺省的数据库，当连接amoeba时，操作表必须显式的指定数据库名，即采用dbname.tablename的方式，不支持 use dbname指定缺省库，因为操作会调度到各个后端dbserver

            <!-- mysql user -->
            <property name="user">test1</property>　　#设置amoeba连接后端数据库服务器的账号和密码，因此需要在所有后端数据库上创建该用户，并授权amoeba服务器可连接

            <property name="password">111111</property>
        </factoryConfig>

        <poolConfig class="com.meidusa.toolkit.common.poolable.PoolableObjectPool">
            <property name="maxActive">500</property>　　#最大连接数，默认500
            <property name="maxIdle">500</property>　　　　#最大空闲连接数
            <property name="minIdle">1</property>　　　　#最新空闲连接数
            <property name="minEvictableIdleTimeMillis"></property>
            <property name="timeBetweenEvictionRunsMillis"></property>
            <property name="testOnBorrow">true</property>
            <property name="testOnReturn">true</property>
            <property name="testWhileIdle">true</property>
        </poolConfig>
    </dbServer>

    <dbServer name="writedb"  parent="abstractServer">　　#设置一个后端可写的dbServer，这里定义为writedb，这个名字可以任意命名，后面还会用到
        <factoryConfig>
            <!-- mysql ip -->
            <property name="ipAddress">192.168.2.204</property> #设置后端可写dbserver
        </factoryConfig>
    </dbServer>

    <dbServer name="slave"  parent="abstractServer">　　#设置后端可读dbserver
        <factoryConfig>
            <!-- mysql ip -->
            <property name="ipAddress">192.168.2.205</property>
        </factoryConfig>
    </dbServer>

    <dbServer name="myslave" virtual="true">　　#设置定义一个虚拟的dbserver，实际上相当于一个dbserver组，这里将可读的数据库ip统一放到一个组中，将这个组的名字命名为myslave
        <poolConfig class="com.meidusa.amoeba.server.MultipleServerPool">
            <!-- Load balancing strategy: =ROUNDROBIN , =WEIGHTBASED , =HA-->
            <property name="loadbalance">1</property>　　#选择调度算法，1表示复制均衡，2表示权重，3表示HA， 这里选择1

            <!-- Separated by commas,such as: server1,server2,server1 -->
            <property name="poolNames">slave</property>　　#myslave组成员
        </poolConfig>
    </dbServer>

</amoeba:dbServers>

另一个配置文件amoeba.xml

[root@bogon amoeba]# cat conf/amoeba.xml
<?xml version="1.0" encoding="gbk"?>

<!DOCTYPE amoeba:configuration SYSTEM "amoeba.dtd">
<amoeba:configuration xmlns:amoeba="http://amoeba.meidusa.com/">

    <proxy>

        <!-- service class must implements com.meidusa.amoeba.service.Service -->
        <service name="Amoeba for Mysql" class="com.meidusa.amoeba.mysql.server.MySQLService">
            <!-- port -->
            <property name="port">8066</property>　　　　#设置amoeba监听的端口，默认是8066

            <!-- bind ipAddress -->　　　　#下面配置监听的接口，如果不设置，默认监听所以的IP
            <!--
            <property name="ipAddress">127.0.0.1</property>
             -->

            <property name="connectionFactory">
                <bean class="com.meidusa.amoeba.mysql.net.MysqlClientConnectionFactory">
                    <property name="sendBufferSize"></property>
                    <property name="receiveBufferSize"></property>
                </bean>
            </property>

            <property name="authenticateProvider">
                <bean class="com.meidusa.amoeba.mysql.server.MysqlClientAuthenticator">
                    

1. # 提供客户端连接amoeba时需要使用这里设定的账号 (这里的账号密码和amoeba连接后端数据库服务器的密码无关)

                    <property name="user">root</property>　　　　

                    <property name="password">123456</property>

                    <property name="filter">
                        <bean class="com.meidusa.toolkit.net.authenticate.server.IPAccessController">
                            <property name="ipFile">${amoeba.home}/conf/access_list.conf</property>
                        </bean>
                    </property>
                </bean>
            </property>

        </service>

        <runtime class="com.meidusa.amoeba.mysql.context.MysqlRuntimeContext">

            <!-- proxy server client process thread size -->
            <property name="executeThreadSize"></property>

            <!-- per connection cache prepared statement size  -->
            <property name="statementCacheSize"></property>

            <!-- default charset -->
            <property name="serverCharset">utf8</property>

            <!-- query timeout( default:  second , TimeUnit:second) -->
            <property name="queryTimeout"></property>
        </runtime>

    </proxy>

    <!--
        Each ConnectionManager will start as thread
        manager responsible for the Connection IO read , Death Detection
    -->
    <connectionManagerList>
        <connectionManager name="defaultManager" class="com.meidusa.toolkit.net.MultiConnectionManagerWrapper">
            <property name="subManagerClassName">com.meidusa.toolkit.net.AuthingableConnectionManager</property>
        </connectionManager>
    </connectionManagerList>

        <!-- default using file loader -->
    <dbServerLoader class="com.meidusa.amoeba.context.DBServerConfigFileLoader">
        <property name="configFile">${amoeba.home}/conf/dbServers.xml</property>
    </dbServerLoader>

    <queryRouter class="com.meidusa.amoeba.mysql.parser.MysqlQueryRouter">
        <property name="ruleLoader">
            <bean class="com.meidusa.amoeba.route.TableRuleFileLoader">
                <property name="ruleFile">${amoeba.home}/conf/rule.xml</property>
                <property name="functionFile">${amoeba.home}/conf/ruleFunctionMap.xml</property>
            </bean>
        </property>
        <property name="sqlFunctionFile">${amoeba.home}/conf/functionMap.xml</property>
        <property name="LRUMapSize"></property>
        <property name="defaultPool">writedb</property>　　#设置amoeba默认的池，这里设置为writedb

        <property name="writePool">writedb</property>　　#这两个选项默认是注销掉的，需要取消注释，这里用来指定前面定义好的俩个读写池
        <property name="readPool">myslave</property>　　 #

        <property name="needParse">true</property>
    </queryRouter>
</amoeba:configuration>

4、在masterdb上创建数据库testdb

mysql> create database testdb;
Query OK,  row affected (0.08 sec)

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mydb               |
| mysql              |
| performance_schema |
| test               |
| testdb             |
+--------------------+
 rows in set (0.00 sec)

查看slavedb是否复制成功

mysql> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| mydb               |
| mysql              |
| performance_schema |
| test               |
| testdb             |
+--------------------+
 rows in set (0.00 sec)

分别在masterdb和slavedb上为amoedb授权

mysql> GRANT ALL ON testdb.* TO 'test1'@'192.168.2.203' IDENTIFIED BY '';
Query OK,  rows affected (0.05 sec)

mysql> flush privileges;
Query OK,  rows affected (0.02 sec)

启动amoeba

[root@bogon amoeba]# /usr/local/amoeba/bin/launcher
Error: JAVA_HOME environment variable is not set.
[root@bogon amoeba]# vim /etc/profile^C
[root@bogon amoeba]# source /etc/profile
[root@bogon amoeba]# /usr/local/amoeba/bin/launcher
Java HotSpot(TM) -Bit Server VM warning: ignoring option PermSize=16m; support was removed in 8.0
Java HotSpot(TM) -Bit Server VM warning: ignoring option MaxPermSize=96m; support was removed in 8.0

The stack size specified is too small, Specify at least 228k
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.

报错:

Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.

从错误文字上看，应该是由于stack size太小，导致JVM启动失败，要如何修改呢？
其实Amoeba已经考虑到这个问题，并将JVM参数配置写在属性文件里。现在，让我们通过该属性文件修改JVM参数。
修改jvm.properties文件JVM_OPTIONS参数。

[root@bogon amoeba]# vim /usr/local/amoeba/jvm.properties
改成：JVM_OPTIONS="-server -Xms1024m -Xmx1024m -Xss256k -XX:PermSize=16m -XX:MaxPermSize=96m"
原为：JVM_OPTIONS="-server -Xms256m -Xmx1024m -Xss196k -XX:PermSize=16m -XX:MaxPermSize=96m"

再次启动

[root@bogon ~]# /usr/local/amoeba/bin/launcher
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchStandard(Launcher.java:)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:)
    at org.codehaus.classworlds.Launcher.mainWithExitCode(Launcher.java:)
    at org.codehaus.classworlds.Launcher.main(Launcher.java:)
Caused by: com.meidusa.toolkit.common.bean.util.InitialisationException: default pool required!,defaultPool=writedb invalid
    at com.meidusa.amoeba.route.AbstractQueryRouter.init(AbstractQueryRouter.java:)
    at com.meidusa.amoeba.context.ProxyRuntimeContext.initAllInitialisableBeans(ProxyRuntimeContext.java:)
    ...  more
 -- :: [INFO] Project Name=Amoeba-MySQL, PID= , System shutdown ....
Java HotSpot(TM) -Bit Server VM warning: ignoring option PermSize=16m; support was removed in 8.0
Java HotSpot(TM) -Bit Server VM warning: ignoring option MaxPermSize=96m; support was removed in 8.0
 -- :: [INFO] Project Name=Amoeba-MySQL, PID= , starting...
log4j:WARN log4j config load completed from file:/usr/local/amoeba/conf/log4j.xml
-- ::, INFO  context.MysqlRuntimeContext - Amoeba for Mysql current versoin=5.1.-mysql-amoeba-proxy-3.0.-BETA
log4j:WARN ip access config load completed from file:/usr/local/amoeba/conf/access_list.conf
-- ::, INFO  net.ServerableConnectionManager - Server listening on 0.0.0.0/0.0.0.0:.

查看端口

[root@bogon ~]# netstat -unlpt | grep java
tcp               :::                     :::*                        LISTEN      /java    

由此可知Amoeba启动正常

5、测试

远程登陆mysql客户端通过指定amoeba配置文件中指定的用户名、密码、和端口以及amoeba服务器ip地址链接mysql数据库

[root@lys2 ~]# mysql -h192.168.2. -uroot -p -P8066
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is
Server version: 5.1.-mysql-amoeba-proxy-3.0.-BETA Source distribution

Copyright (c) , , 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> 

在testdb中创建表test并插入数据

mysql> use testdb;
Database changed
mysql> create table test_table(id int,password varchar() not null);
Query OK,  rows affected (0.19 sec)

mysql> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| test_table       |
+------------------+
 row in set (0.02 sec)

mysql> insert into test_table(id,password) values('','test1');
Query OK,  row affected (0.04 sec)

mysql> select * from test_table;
+------+----------+
| id   | password |
+------+----------+
|     | test1    |
+------+----------+
 row in set (0.02 sec)

分别登陆masterdb和slavedb查看数据

masterdb：

mysql> use testdb;
Database changed
mysql> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| test_table       |
+------------------+
 row in set (0.00 sec)

mysql> select * from test_table;
+------+----------+
| id   | password |
+------+----------+
|     | test1    |
+------+----------+
 row in set (0.03 sec)

slavedb：

mysql> use testdb;
Database changed
mysql> show tables;
+------------------+
| Tables_in_testdb |
+------------------+
| test_table       |
+------------------+
 row in set (0.00 sec)

mysql> select * from test_table;
+------+----------+
| id   | password |
+------+----------+
|     | test1    |
+------+----------+
 row in set (0.00 sec)

停掉masterdb，然后在客户端分别执行插入和查询功能

masterdb：

　　[root@bogon ~]# service mysqld stop
　　Shutting down MySQL. SUCCESS!

客户端：

mysql> insert into test_table(id,password) values('','test2');
ERROR  (): Amoeba could not connect to MySQL server[192.168.2.204:],拒绝连接
mysql> select * from test_table;
+------+----------+
| id   | password |
+------+----------+
|     | test1    |
+------+----------+
 row in set (0.01 sec)

可以看到，关掉masterdb和写入报错，读正常

开启masterdb上的msyql 关闭slave上的mysql

masterdb：

[root@bogon ~]# service mysqld start
Starting MySQL.. SUCCESS! 

slavedb：

[root@localhost ~]# service mysqld stop
Shutting down MySQL. SUCCESS! 

客户端再次尝试

mysql> insert into test_table(id,password) values('','test2');
Query OK,  row affected (0.19 sec)

mysql> select * from test_table;
ERROR  (): poolName=myslave, no valid pools

可以看到插入成功，读取失败

开启slavedb上的mysql，查看数据是否自动同步

slavedb:

[root@localhost ~]# service mysqld start
Starting MySQL... SUCCESS! 

客户端：

mysql> select * from test_table;
+------+----------+
| id   | password |
+------+----------+
|     | test1    |
|     | test2    |
+------+----------+
 rows in set (0.01 sec)

接着客户端：

mysql> insert into test_table(id,password) values('','test3');
Query OK,  row affected (0.03 sec)

mysql> select * from test_table;
+------+----------+
| id   | password |
+------+----------+
|     | test1    |
|     | test2    |
|     | test3    |
+------+----------+
 rows in set (0.02 sec)

OK 一切正常，到此全部结束

注：关于mysql主从同步自行查看博主之前的主从同步笔记！

Amoeba主配置文件($AMOEBA_HOME/conf/amoeba.xml)，用来配置Amoeba服务的基本参数，如Amoeba主机地址、端口、认证方式、用于连接的用户名、密码、线程数、超时时间、其他配置文件的位置等。

数据库服务器配置文件($AMOEBA_HOME/conf/dbServers.xml)，用来存储和配置Amoeba所代理的数据库服务器的信息，如:主机IP、端口、用户名、密码等。

切分规则配置文件($AMOEBA_HOME/conf/rule.xml)，用来配置切分规则。

数据库函数配置文件($AMOEBA_HOME/conf/functionMap.xml)，用来配置数据库函数的处理方法，Amoeba将使用该配置文件中的方法解析数据库函数。

切分规则函数配置文件($AMOEBA_HOME/conf/ruleFunctionMap.xml)，用来配置切分规则中使用的用户自定义函数的处理方法。

访问规则配置文件($AMOEBA_HOME/conf/access_list.conf)，用来授权或禁止某些服务器IP访问Amoeba。

日志规格配置文件($AMOEBA_HOME/conf/log4j.xml)，用来配置Amoeba输出日志的级别和方式。