1.前言
maxscale是mariadb公司开发的一套数据库中间件,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。另外maxscale对于前端应用而言是透明的,我们可以很方便的将应用迁移到maxscale中实现读写分离方案,来分担主库的压力。maxscale也提供了sql语句的解析过滤功能。这里我们主要讲解maxscale的安装、配置以及注意事项。
2.安装环境
使用我之前的MHA环境
1)server1(node节点)
OS:CentOS 6.4 X64
IPADDR:172.16.21.12(eth0);192.168.8.6(eth1)
HOSTNAME:MySQL-mha01
DB:Mariadb10.0.21
防火墙关闭;selinux关闭;
2)server2(node节点)
OS:CentOS 6.4 X64
IPADDR:172.16.21.13(eth2);192.168.8.7(eth3)
HOSTNAME:mysql-mha02
DB:DB:Mariadb10.0.21
防火墙关闭;selinux关闭;
3)server3(node节点,manager节点)
OS:CentOS 6.4 X64
IPADDR:172.16.21.15(eth2);192.168.8.8(eth3)
HOSTNAME:mysql-mha01
DB:DB:Mariadb10.0.21
防火墙关闭;selinux关闭;
使用软件:maxscale-1.4.1-1.rhel_6.x86_64.rpm
3.安装软件
在主节点192.168.8.7上安装maxscale
- yum install maxscale-1.4.1-1.rhel_6.x86_64.rpm
- mkdir -p /maxscale/cache
- mkdir -p /maxscale/data
- mkdir -p /maxscale/log
- mkdir -p /maxscale/pid
- mkdir -p /maxscale/tmp
4.maxscale配置
4.1配置文件
- [root@mysql-mha02 etc]# cat /etc/maxscale.cnf
- # MaxScale documentation on GitHub:
- # https://github.com/mariadb-corporation/MaxScale/blob/master/Documentation/Documentation-Contents.md
- # Global parameters
- #
- # Complete list of configuration options:
- # https://github.com/mariadb-corporation/MaxScale/blob/master/Documentation/Getting-Started/Configuration-Guide.md
- [maxscale]
- threads=auto #开启线程个数,默认为1.设置为auto会同cpu核数相同
- ms_timestamp=1 #timestamp精度
- syslog=1 #将日志写入到syslog中
- maxlog=1 #将日志写入到maxscale的日志文件中
- log_to_shm=0 #不将日志写入到共享缓存中,开启debug模式时可打开加快速度
- log_warning=1 #记录告警信息
- log_notice=1 #记录notice
- log_info=1 #记录info
- log_debug=0 #不打开debug模式
- log_augmentation=1 #日志递增
- #相关目录设置
- logdir=/maxscale/log/
- datadir=/maxscale/data/
- libdir=/usr/lib64/maxscale/
- cachedir=/maxscale/cache/
- piddir=/maxscale/pid/
- execdir=/usr/bin/
- # Server definitions
- #
- # Set the address of the server to the network
- # address of a MySQL server.
- #
- [server1]
- type=server
- address=192.168.8.6
- port=3306
- protocol=MySQLBackend
- [server2]
- type=server
- address=192.168.8.7
- port=3306
- protocol=MySQLBackend
- [server3]
- type=server
- address=192.168.8.8
- port=3306
- protocol=MySQLBackend
- # Monitor for the servers
- #
- # This will keep MaxScale aware of the state of the servers.
- # MySQL Monitor documentation:
- # https://github.com/mariadb-corporation/MaxScale/blob/master/Documentation/Monitors/MySQL-Monitor.md
- #相关的监控信息,监控的用户需要对后端数据库有访问replication client的权限:grant replication client
- [MySQL Monitor]
- type=monitor
- module=mysqlmon
- servers=server1,server2,server3
- user=root
- passwd=7AE087FBF864EBB87D108C3AB1603D0D
- monitor_interval=1000 #监控心跳为1秒
- detect_replication_lag=true #监控主从复制延迟,可用后续指定router service的max_slave_replication_lag单位是秒,来控制maxscale运行的最大延迟
- detect_stale_master=true #当复制slave全部断掉时,maxscale仍然可用,将所有的访问指向master节点
- # Service definitions
- #
- # Service Definition for a read-only service and
- # a read/write splitting service.
- #
- # ReadConnRoute documentation:
- # https://github.com/mariadb-corporation/MaxScale/blob/master/Documentation/Routers/ReadConnRoute.md
- #read-only的只读节点slave分离
- [Read-Only Service]
- type=service
- router=readconnroute
- servers=server1,server2,server3
- user=root
- passwd=7AE087FBF864EBB87D108C3AB1603D0D
- router_options=slave
- enable_root_user=1
- # ReadWriteSplit documentation:
- # https://github.com/mariadb-corporation/MaxScale/blob/master/Documentation/Routers/ReadWriteSplit.md
- #读写分离,用户需要有SELECT ON mysql.db;SELECT ON mysql.tables_priv;SHOW DATABASES ON *.*的权限
- [Read-Write Service]
- type=service
- router=readwritesplit
- servers=server1,server2,server3
- user=root
- passwd=7AE087FBF864EBB87D108C3AB1603D0D
- use_sql_variables_in=master #sql语句中的存在变量只指向master中执行
- enable_root_user=1 #允许root用户登录执行
- master_accept_reads=true #master节点也可以转发读请求
- max_slave_replication_lag=5 #复制延迟最大为5秒(必须比monitor的interval大)
- #maxscale管理节点信息
- [MaxAdmin Service]
- type=service
- router=cli
- # Listener definitions for the services
- #
- # These listeners represent the ports the
- # services will listen on.
- #
- #各个请求的端口信息
- [Read-Only Listener]
- type=listener
- service=Read-Only Service
- protocol=MySQLClient
- port=4008
- [Read-Write Listener]
- type=listener
- service=Read-Write Service
- protocol=MySQLClient
- port=4006
- [MaxAdmin Listener]
- type=listener
- service=MaxAdmin Service
- protocol=maxscaled
- port=6603
4.2加密密码
配置文件中的密码都是经过maxscale进行加密后的,可以防止密码泄露,具体的操作步骤为
在刚才配置文件中的datadir目录下创建加密文件
- maxkeys /maxscale/keys/.secrets
生成加密后的密码
- [root@mysql-mha02 data]# maxpasswd /maxscale/data/.secrets 123456
- 7AE087FBF864EBB87D108C3AB1603D0D
4.3启动maxscale
- maxscale -f /etc/maxscale.cnf
5.验证读写分离
5.1创建测试表
在主节点server2 192.168.8.7上建立测试表
- MariaDB [test]> create table test_maxscale(id int);
- Query OK, 0 rows affected (0.02 sec)
- MariaDB [test]> insert into test_maxscale values(87);
- Query OK, 1 row affected (0.02 sec)
- MariaDB [test]> select * from test_maxscale;
- +------+
- | id |
- +------+
- | 87 |
- +------+
- 1 row in set (0.00 sec)
- MariaDB [test]> insert into test_maxscale values(86);
- MariaDB [test]> select * from test_maxscale;
- +------+
- | id |
- +------+
- | 87 |
- | 86 |
- +------+
- 2 rows in set (0.00 sec)
- MariaDB [test]> insert into test_maxscale values(88);
- Query OK, 1 row affected (0.00 sec)
- MariaDB [test]> select * from test_maxscale;
- +------+
- | id |
- +------+
- | 87 |
- | 88 |
- +------+
- 2 rows in set (0.00 sec)
5.2只读访问maxscale
通过mysql命令行访问maxscale所在节点192.168.8.7的读写分离listener 4006端口
- [root@mysql-mha01 ~]# mysql -P4006 -uroot -p123456 -h192.168.8.7 -e "select * from test.test_maxscale;"
- +------+
- | id |
- +------+
- | 87 |
- | 86 |
- +------+
5.3读写分离
加入包含insert的sql语句
- [root@mysql-mha02 log]# mysql -P4006 -uroot -p123456 -h192.168.8.7 -e "insert into test.test_maxscale values(90);select * from test.test_maxscale;"
- +------+
- | id |
- +------+
- | 87 |
- | 88 |
- | 90 |
- +------+
在server2主节点中
在server1另一个slave节点中
- MariaDB [(none)]> select * from test.test_maxscale;
- +------+
- | id |
- +------+
- | 87 |
- | 90 |
- +------+
- 2 rows in set (0.00 sec)
- MariaDB [test]> select * from test_maxscale;
- +------+
- | id |
- +------+
- | 87 |
- | 86 |
- | 90 |
- +------+
- 3 rows in set (0.00 sec)
6.注意事项
这里我主要讲些重点需要注意的:
1)创建链接的时候,不支持压缩协议
2)转发路由不能动态的识别master节点的迁移
3)LONGLOB字段不支持
4)在一下情况会将语句转到master节点中(保证事务一致):
明确指定事务;
prepared的语句;
语句中包含存储过程,自定义函数
包含多条语句信息:
INSERT INTO ... ; SELECT LAST_INSERT_ID();
5)一些语句默认会发送到后端的所有server中,但是可以指定
use_sql_variables_in=[master|all] (default: all)
为master的时候可以将语句都转移到master 上执行。但是自动提交值和prepared的语句仍然发送到所有后端server。
这些语句为
- COM_INIT_DB (USE <db name> creates this)
- COM_CHANGE_USER
- COM_STMT_CLOSE
- COM_STMT_SEND_LONG_DATA
- COM_STMT_RESET
- COM_STMT_PREPARE
- COM_QUIT (no response, session is closed)
- COM_REFRESH
- COM_DEBUG
- COM_PING
- SQLCOM_CHANGE_DB (USE ... statements)
- SQLCOM_DEALLOCATE_PREPARE
- SQLCOM_PREPARE
- SQLCOM_SET_OPTION
- SELECT ..INTO variable|OUTFILE|DUMPFILE
- SET autocommit=1|0
6)maxscale不支持主机名匹配的认证模式,只支持IP地址方式的host解析。所以在添加user的时候记得使用合适的范式。
7)跨库查询不支持,会显示的指定到第一个数据库中
8)通过select方式改变会话变量的行为不支持