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。
2 环境说明
主机IP 角色 Server-id 操作系统版本
192.168.1.67 Master 77
RedHat7.3
192.168.1.68 Slave 78 Redhat7.3
192.168..1.69 Slave 79 Redhat7.3
3 MaxScale版本
https://downloads.mariadb.com/MaxScale/
https://downloads.mariadb.com/MaxScale/2.2.0/rhel/7server/x86_64/maxscale-2.2.0-1.rhel.7.x86_64.rpm
3.1 安装
将maxscale安装在主节点
rpm -ivh maxscale-2.2.0-1.rhel.7.x86_64.rpm
3.2 创建所需目录
mkdir -p /maxscale/cache
mkdir -p /maxscale/data
mkdir -p /maxscale/log
mkdir -p /maxscale/pid
mkdir -p /maxscale/tmp
3.3 创建用户
create user 'jiankongdb'@'%' identified by 'jiankong123';
grant SELECT on
MySQL.user to 'jiankongdb'@'%';
GRANT SELECT ON mysql.db TO 'jiankongdb'@'%';
GRANT all ON *.* TO 'jiankongdb'@'%';
GRANT SHOW DATABASES ON *.* TO 'jiankongdb'@'%';
grant REPLICATION CLIENT on *.* to 'jiankongdb'@'%';
GRANT replication slave, replication client,SELECT ON *.* TO jiankongdb@'%';
3.4 配置MaxScale
详细参数说明参考官方文档：
https://mariadb.com/kb/en/mariadb-enterprise/mariadb-maxscale-21-mariadb-maxscale-configuration-usage-scenarios/
编辑配置文件/etc/maxscale.cnf
[root@ data]# cat /etc/maxscale.cnf
# MaxScale documentation on GitHub:
# https://github.com/mariadb-corporation/MaxScale/blob/2.1/Documentation/Documentation-Contents.md
# Global parameters
#
# Complete list of configuration options:
# https://github.com/mariadb-corporation/MaxScale/blob/2.1/Documentation/Getting-Started/Configuration-Guide.md
[maxscale]
threads=auto
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=192.168.1.67
port=3306
protocol=MySQLBackend
#serv_weight=1
[server2]
type=server
address=192.168.1.68
port=3306
protocol=MySQLBackend
#serv_weight=3
[server3]
type=server
address=192.168.1.69
port=3306
protocol=MySQLBackend
#serv_weight=4
# 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/2.1/Documentation/Monitors/MySQL-Monitor.md
[MySQL Monitor]
type=monitor
module=mysqlmon
servers=server1,server2,server3
user=jiankongdb
passwd=jiankong123
monitor_interval=10000
detect_stale_master=true
# Service definitions
#
# Service Definition for a read-only service and
# a read/write splitting service.
#
# ReadConnRoute documentation:
# https://github.com/mariadb-corporation/MaxScale/blob/2.1/Documentation/Routers/ReadConnRoute.md
[Read-Only Service]
type=service
router=readconnroute
servers=server1,server2,server3
user=jiankongdb
passwd=jiankong123
router_options=slave
enable_root_user=1
weightby=serv_weight
# ReadWriteSplit documentation:
# https://github.com/mariadb-corporation/MaxScale/blob/2.1/Documentation/Routers/ReadWriteSplit.md
[Read-Write Service]
type=service
router=readwritesplit
servers=server1,server2,server3
user=jiankongdb
passwd=jiankong123
max_slave_connections=100%
use_sql_variables_in=master
enable_root_user=1
max_slave_replication_lag=3600
# This service enables the use of the MaxAdmin interface
# MaxScale administration guide:
# https://github.com/mariadb-corporation/MaxScale/blob/2.1/Documentation/Reference/MaxAdmin.md
[MaxAdmin Service]
type=service
router=cli
# Listener definitions for the services
#
# These listeners represent the ports the
# services will listen on.
#
[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
socket=default
3.5 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
[root@ data]#maxkeys /maxscale/data
生成加密后的密码
[root@ data]# maxpasswd /maxscale/data/ jiankong123
D88ED80AE158722A2A3FD725E906C601
1787C217C118C9B0F9A44DCB8B178414就是123加密后的密码。我们可以添加到配置文件中。
3.6 启动MaxScale
maxscale -f /etc/maxscale.cnf
3.7 查看MaxScale 状态
[root@ software]# maxadmin list servers
Servers.
-------------------+-----------------+-------+-------------+--------------------
Server
| Address
| Port | Connections | Status
-------------------+-----------------+-------+-------------+--------------------
server1
| 192.168.1.67 | 3306 |
0 | Master, Running
server2
| 192.168.1.68 | 3306 |
0 | Slave, Running
server3
| 192.168.1.69 | 3306 |
0 | Slave, Running
-------------------+-----------------+-------+-------------+--------------------
或者
[root@ log]# maxadmin -uadmin -pmariadb
MaxScale> list servers
Servers.
-------------------+-----------------+-------+-------------+--------------------
Server
| Address
| Port | Connections | Status
-------------------+-----------------+-------+-------------+--------------------
server1
| 192.168.1.67 | 3306 |
0 | Master, Running
server2
| 192.168.1.68 | 3306 |
0 | Slave, Running
server3
| 192.168.1.69 | 3306 |
0 | Slave, Running
-------------------+-----------------+-------+-------------+--------------------
4 验证读写分离
4.1 创建测试表
在主节点server1 192.168.1.67上建立测试表
MariaDB [cndba2]> create table test_maxscale(id int);
Query OK, 0 rows affected (0.02 sec)
MariaDB [cndba2]> insert into test_maxscale values(87);
Query OK, 1 row affected (0.02 sec)
MariaDB [cndba2]> select * from test_maxscale;
+------+
| id |
+------+
| 87 |
+------+
1 row in set (0.00 sec)
在节点server2 192.168.1.68上额外加入测试信息
MariaDB [cndba2]> insert into test_maxscale values(86);
MariaDB [cndba2]> select * from test_maxscale;
+------+
| id |
+------+ s
| 87 |
| 86 |
+------+
2 rows in set (0.00 sec)
在节点server3 192.168.1.69上额外加入测试信息
MariaDB [cndba2]> insert into test_maxscale values(88);
Query OK, 1 row affected (0.00 sec)
MariaDB [cndba2]> select * from test_maxscale;
+------+
| id |
+------+
| 87 |
| 88 |
+------+
2 rows in set (0.00 sec)
4.2 只读访问maxscale
通过mysql命令行访问maxscale所在节点192.168.1.78的读写分离listener 4006端口
[root@ data]# mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select * from cndba2.test_maxscale;"
+------+
| id |
+------+
| 87 |
| 86 |
+------+发现分到了server2上面
4.3 读写分离
加入包含insert的sql语句
[root@ data]# mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "insert into cndba2.test_maxscale values(90);select * from cndba2.test_maxscale;"
+------+
| id |
+------+
| 87 |
| 86 |
| 90 |
+------+
发现转发到server2中，但是也包含90的值，我们需要到主节点server3和另外一个slave进行验证
在server1主节点中
MariaDB [(none)]> select * from cndba2.test_maxscale;
+------+
| id |
+------+
| 87 |
| 90 |
+------+
2 rows in set (0.00 sec)
在server3另一个slave节点中
MariaDB [cndba2]> select * from test_maxscale;
+------+
| id |
+------+
| 87 |
| 88 |
| 90 |
+------+
3 rows in set (0.00 sec)
maxscale实现了读写分离。
5 验证负载均衡
5.1 查看Read-Write Service
[root@ mysql]# maxadmin -uadmin -pmariadb
MaxScale> show service "Read-Write-Service"
Service:
Read-Write-Service
Router:
readwritesplit
State:
Started
use_sql_variables_in:
master
slave_selection_criteria: LEAST_CURRENT_OPERATIONS
master_failure_mode:
fail_instantly
max_slave_replication_lag: 3600
retry_failed_reads:
true
strict_multi_stmt:
true
strict_sp_calls:
false
disable_sescmd_history: true
max_sescmd_history:
0
master_accept_reads:
false
Number of router sessions:
121
Current no. of router sessions:
1
Number of queries forwarded:
272
Number of queries forwarded to master: 0 (0.00%)
Number of queries forwarded to slave:
272 (100.00%)
Number of queries forwarded to all:
121 (44.49%)
Started:
Mon Nov 27 23:53:13 2017
Root user access:
Enabled
Backend databases:
[192.168.1.67]:3306 Protocol: MySQLBackend Name: server1
[192.168.1.68]:3306 Protocol: MySQLBackend Name: server2
[192.168.1.69]:3306 Protocol: MySQLBackend Name: server3
Total connections:
122
Currently connected:
1
5.2 测试结果
[root@ mysql]# for i in `seq 1 10`; do mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2>/dev/null & done
[1] 3963
[2] 3964
[3] 3965
[4] 3966
[5] 3967
[6] 3968
[7] 3969
[8] 3970
[9] 3971
[10] 3972
[root@ mysql]# +------------+
| @@hostname |
+------------+
| mariadb2 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb3 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb3 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb2 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb2 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb3 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb2 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb3 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb2 |
+------------+
+------------+
| @@hostname |
+------------+
| mariadb3 |
+------------+
[1] Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[2] Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[3] Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[4] Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[5] Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[6] Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[7] Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[8] Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[9]- Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
[10]+ Done
mysql -P4006 -ujiankongdb -pjiankong123 -h192.168.1.67 -e "select @@hostname;" 2> /dev/null
可以看到会话被平均分配到两个节点上
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