使用Maxscale实现mysql读写分离

MaxScale 是 MariaDB 的产品之一，可以很方便的实现读写分离方案；并且提供了读写分离的负载均衡和高可用性保障。

一、安装配置

前提：先配置好mysql的主从，Maxscale会自动的根据主从复制信息来判断Master和slave

注：不能配置mysql互为主从，如果互为主从，两台都会被认为slave,在这种情况下，写请求会被拒绝，只接受读请求。

1.1.安装

官网下载对应的rpm包，

wget  https://downloads.mariadb.com/MaxScale/2.0.3/centos/6server/x86_64/maxscale-2.0.3-1.centos.6.x86_64.rpmrpm -ivh maxscale-2.0.3-1.centos.6.x86_64.rpm

maxscale的配置文件为:/etc/maxscale.conf，配置文件由多个配置模块组成

vi /etc/maxscale.conf#全局配置：[maxscale]threads=autolog_info=1log_notice=1log_warning=1#后端mysql定义[server1]type=serveraddress=192.168.10.1port=3306protocol=MySQLBackend[server2]type=serveraddress=192.168.10.2port=3306protocol=MySQLBackend#监控配置[MySQL Monitor] type=monitormodule=mysqlmon      #监控模块默认使用mysqlmon,当然还有其他可选择的模块servers=server1,server2user=admin        #admin监控后端mysql的复制状况，必须具有REPLICATION CLIENT权限      passwd=123456monitor_interval=10000#触发器定义 注意，以下两句的上下顺序不能变，不然无法生效script=/opt/mysql_monitor.sh  #定义事件触发脚本执行events=master_down       #事件触发器当master down时，执行上面的脚本,maxscale内置了很                                 多的events#读写分离service[Read-Write Service] type=servicerouter=readwritesplit       #读写分离路由模式servers=server1,server2user=maxscale    #该用户从后端mysql获取用户信息，对客户端进行身份验证，必须具有mysql.user table的select权限                passwd=maxscalemax_slave_connections=100%                   max_slave_replication_lag=3600000   #当slave的数据落后master小于3600秒时仍然可用connection_timeout=300                          router_options=master_failure_mode=error_on_write #允许master down掉，slave仍然可读#router_options=master_accept_reads=true      #允许master接受读请求[Read-Write Listener] type=listenerservice=Read-Write Serviceprotocol=MySQLClientport=3306#管理服务配置 [MaxAdmin Service]type=servicerouter=cli#管理服务监听[MaxAdmin Listener]type=listenerservice=MaxAdmin Serviceprotocol=maxscaledsocket=default

二、管理

Maxscale提供了maxadmin命令用于查看管理

[root@server ~]# maxadmin  list -Unknown or missing option for the list command. Valid sub-commands are:    clients    List all the client connections to MaxScale    dcbs       List all the DCBs active within MaxScale    filters    List all the filters defined within MaxScale    listeners  List all the listeners defined within MaxScale    modules    List all currently loaded modules    monitors   List all monitors    services   List all the services defined within MaxScale    servers    List all the servers defined within MaxScale    sessions   List all the active sessions within MaxScale    threads    List the status of the polling threads in MaxScale

[root@server ~]# maxadmin list serversServers.-------------------+-----------------+-------+-------------+--------------------Server             | Address         | Port  | Connections | Status              -------------------+-----------------+-------+-------------+--------------------server1            | 192.168.10.1      |  3306 |           0 | Master, Runningserver2            | 192.168.10.2     |  3306 |           0 | Slave, Running-------------------+-----------------+-------+-------------+--------------------

三、高可用性

Maxscale默认只提供读的高可用性，要实现写的高可用性，可以使用两种途径：

1.需要使用Multi-MasterMonitor监控模块，不同于上文使用的mysqlmon模块，该模块是通过read_only参数来选举Master和Slave,结合脚本可以实现在Master fail的时候，取消slave的read_only属性，将slave提升为Master

2.使用高可用软件MMM