前言
关于MySQL中间件的产品也很多,之前用过了360的Atlas、玩过MyCat。这边我选择 Maxscale的原因就是功能能满足需求,也看好他的未来发展。
其实有关于如何安装 Maxscale的文章百度一下一大把，写这篇文章主要为了说明配置的某些现象，同时也为之后使用Maxscale的其他配置做下基础。
我的环境
这边我的'一主二从'已经是搭建好的了，如何搭建就不再描述了。
注意：这边我的三个节点都没有开启 GTID，具体是为什么在之后会讲到，这边大家留意一下就行。
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192.168.137.11 (Maxscale)
192.168.137.21:3306 (Master)
192.168.137.22:3306 (Slave)
192.168.137.23:3306 (Slave)
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这边我使用的用于复制的用户是maxscale,具体权限如下:
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CREATE USER maxscale@'%' IDENTIFIED BY "123456";
GRANT replication slave, replication client ON *.* TO maxscale@'%';
GRANT SELECT ON mysql.* TO maxscale@'%';
GRANT ALL ON maxscale_schema.* TO maxscale@'%';
GRANT SHOW DATABASES ON *.* TO maxscale@'%';
root@(none) 22:34:15>SELECT VERSION();
+--------------------+
| VERSION() |
+--------------------+
| 10.1.8-MariaDB-log |
+--------------------+
1 row in set (0.00 sec)
root@(none) 22:34:25>SHOW SLAVE HOSTS;
+------------+----------------+------+------------+
| Server_id | Host | Port | Master_id |
+------------+----------------+------+------------+
| 3306137022 | 192.168.137.21 | 3306 | 3306137021 |
| 3306137023 | 192.168.137.21 | 3306 | 3306137021 |
+------------+----------------+------+------------+
2 rows in set (0.00 sec)
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下载Maxscale
在 192.168.137.11 机器上
这边提供下载地址: https://downloads.mariadb.com
我的版本
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[root@normal_11 opt]# pwd
/opt
[root@normal_11 opt]# ll
total 149624
-rw-r--r-- 1 root root 3587510 Nov 2 21:07 maxscale-2.0.1.centos.7.tar.gz
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开始安装
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[root@normal_11 opt]# groupadd maxscale
[root@normal_11 opt]# useradd -g maxscale maxscale
[root@normal_11 opt]# cd /opt
[root@normal_11 opt]# tar -zxf maxscale-2.0.1.centos.7.tar.gz
[root@normal_11 opt]# ln -s maxscale-2.0.1.centos.7 /usr/local/maxscale
[root@normal_11 opt]# chown -R maxscale:maxscale /usr/local/maxscale
[root@normal_11 opt]# mkdir -p /u01/maxscale/{data,cache,logs,tmp}
[root@normal_11 opt]# mkdir -p /u01/maxscale/logs/{binlog,trace}
[root@normal_11 opt]# chown -R maxscale:maxscale /u01/maxscale
[root@normal_11 opt]# /usr/local/maxscale/bin/maxkeys /u01/maxscale/data/
[root@normal_11 opt]# /usr/local/maxscale/bin/maxpasswd /u01/maxscale/data/.secrets 123456
1D30C1E689410756D7B82C233FCBF8D9
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Maxscale 配置文件
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[root@normal_11 opt]# cat /etc/maxscale.cnf
###################################################
# CREATE USER maxscale@'%' IDENTIFIED BY "123456";
# GRANT replication slave, replication client ON *.* TO maxscale@'%';
# GRANT SELECT ON mysql.* TO maxscale@'%';
# GRANT ALL ON maxscale_schema.* TO maxscale@'%';
# GRANT SHOW DATABASES ON *.* TO maxscale@'%';
# groupadd maxscale
# useradd -g maxscale maxscale
# cd /opt
# tar -zxf maxscale-2.0.1.rhel.7.tar.gz
# ln -s /opt/maxscale-2.0.1.rhel.7 /usr/local/maxscale
# chown -R maxscale:maxscale /usr/local/maxscale
# mkdir -p /u01/maxscale/{data,cache,logs,tmp}
# mkdir -p /u01/maxscale/logs/{binlog,trace}
# chown -R maxscale:maxscale /u01/maxscale
# /usr/local/maxscale/bin/maxkeys /u01/maxscale/data/
# /usr/local/maxscale/bin/maxpasswd /u01/maxscale/data/.secrets 123456
###################################################
[maxscale]
# 开启线程个数，默认为1.设置为auto会同cpu核数相同
threads=auto
# timestamp精度
ms_timestamp=1
# 将日志写入到syslog中
syslog=1
# 将日志写入到maxscale的日志文件中
maxlog=1
# 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_to_shm=0
# 记录告警信息
log_warning=1
# 记录notice
log_notice=1
# 记录info
log_info=1
# 不打开debug模式
log_debug=0
# 日志递增
log_augmentation=1
# 相关目录设置
basedir=/usr/local/maxscale/
logdir=/u01/maxscale/logs/trace/
datadir=/u01/maxscale/data/
cachedir=/u01/maxscale/cache/
piddir=/u01/maxscale/tmp/
[server1]
type=server
address=192.168.137.21
port=3306
protocol=MySQLBackend
serv_weight=1
[server2]
type=server
address=192.168.137.22
port=3306
protocol=MySQLBackend
serv_weight=3
[server3]
type=server
address=192.168.137.23
port=3306
protocol=MySQLBackend
serv_weight=3
[MySQL Monitor]
type=monitor
module=mysqlmon
servers=server1,server2,server3
user=maxscale
passwd=1D30C1E689410756D7B82C233FCBF8D9
# 监控心态为 10s
monitor_interval=10000
# 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
detect_stale_master=true
# 监控主从复制延迟，可用后续指定router service的(配置此参数请求会永远落在 master)
# detect_replication_lag=true
[Read-Only Service]
type=service
router=readconnroute
servers=server1,server2,server3
user=maxscale
passwd=1D30C1E689410756D7B82C233FCBF8D9
router_options=slave
# 允许root用户登录执行
enable_root_user=1
# 查询权重
weightby=serv_weight
[Read-Write Service]
type=service
router=readwritesplit
servers=server1,server2,server3
user=maxscale
passwd=1D30C1E689410756D7B82C233FCBF8D9
max_slave_connections=100%
# sql语句中的存在变量只指向master中执行
use_sql_variables_in=master
# 允许root用户登录执行
enable_root_user=1
# 允许主从最大间隔(s)
max_slave_replication_lag=3600
[MaxAdmin Service]
type=service
router=cli
[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=/u01/maxscale/tmp/maxadmin.sock
port=6603
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细心的朋友会注意到, 的我配置文件最上面就是安装 Maxscale 的基本步骤，这是本人的一个习惯.
这边我稍微说明一下配置文件的意思:
- [server1], [server2], [server3] 我配置了三个Maxscale需要连接的MySQL服务
- [MySQL Monitor] 配置一个监听服务, 同时监听着 [server1], [server2], [server3] 的状态
- [Read-Only Service] 配置了只读服务, 只在[server2], [server3]中执行
注意: 虽然是只读服务但是同样可以执行 DML DDL, 说以要限制好用户的权限.
- [Read-Write Listener] 配置了读写分离的服务
- [MaxAdmin Listener] 配置了用户管理Maxscale的服务
演示
这边我们以 [Read-Write Listener] 配置的服务来演示读写分离情况
- 启动 Maxscale
如果启动有报错那就查看一下日志 /var/log/message 或 /u01/maxscale/logs/trace/maxscale1.log(自定义)
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[root@normal_11 opt]# /usr/local/maxscale/bin/maxscale -f /etc/maxscale.cnf
[root@normal_11 opt]# netstat -natpl | grep max
tcp 0 0 0.0.0.0:4008 0.0.0.0:* LISTEN 5507/maxscale
tcp 0 0 0.0.0.0:6603 0.0.0.0:* LISTEN 5507/maxscale
tcp 0 0 0.0.0.0:4006 0.0.0.0:* LISTEN 5507/maxscale
tcp 0 0 192.168.137.11:43102 192.168.137.22:3306 ESTABLISHED 5507/maxscale
tcp 0 0 192.168.137.11:54624 192.168.137.21:3306 ESTABLISHED 5507/maxscale
tcp 0 0 192.168.137.11:52989 192.168.137.23:3306 ESTABLISHED 5507/maxscale
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- 使用 maxadmin 查看服务
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[root@normal_11 opt]# /usr/local/maxscale/bin/maxadmin -S /u01/maxscale/tmp/maxadmin.sock
MaxScale> list servers
Servers.
-------------------+-----------------+-------+-------------+--------------------
Server | Address | Port | Connections | Status
-------------------+-----------------+-------+-------------+--------------------
server1 | 192.168.137.21 | 3306 | 0 | Master, Running
server2 | 192.168.137.22 | 3306 | 0 | Slave, Running
server3 | 192.168.137.23 | 3306 | 0 | Slave, Running
-------------------+-----------------+-------+-------------+--------------------
MaxScale> list services
Services.
--------------------------+----------------------+--------+---------------
Service Name | Router Module | #Users | Total Sessions
--------------------------+----------------------+--------+---------------
Read-Only Service | readconnroute | 1 | 1
Read-Write Service | readwritesplit | 1 | 1
MaxAdmin Service | cli | 3 | 3
--------------------------+----------------------+--------+---------------
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通过登录Maxscale的读写分离服务, 来执行sql并且查看日志，查看日志路由情况。
注意: 这边登录的用户就是普通的MySQL用户, 不是maxscale用户
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[root@normal_11 opt]# mysql -uHH -p -h192.168.137.11 -P4006
Logging to file '/u01/mysql_history/query.log'
Enter password:
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 5524
Server version: 5.5.5-10.0.0 2.0.1-maxscale MariaDB Server
Copyright (c) 2009-2015 Percona LLC and/or its affiliates
Copyright (c) 2000, 2015, 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.
HH@192.168.137.11 11:13:46 [(none)]>SELECT * FROM test.t1;
+----+------+-----+
| id | name | age |
+----+------+-----+
| 1 | HH1 | 1 |
| 2 | HH2 | 2 |
| 3 | HH3 | 3 |
+----+------+-----+
3 rows in set (0.01 sec)
HH@192.168.137.11 11:15:03 [(none)]>INSERT INTO test.t1 VALUES(NULL, 'HH4', 4);
Query OK, 1 row affected (0.01 sec)
# 使用 HH 登录成的日志
2016-11-03 23:13:46.907 info : (log_server_connections): Servers and router connection counts:
2016-11-03 23:13:46.907 info : (log_server_connections): current operations : 0 in 192.168.137.21:3306 RUNNING MASTER
2016-11-03 23:13:46.907 info : (log_server_connections): current operations : 0 in 192.168.137.22:3306 RUNNING SLAVE
2016-11-03 23:13:46.907 info : (log_server_connections): current operations : 0 in 192.168.137.23:3306 RUNNING SLAVE
2016-11-03 23:13:46.908 info : (select_connect_backend_servers): Selected RUNNING MASTER in 192.168.137.21:3306
2016-11-03 23:13:46.908 info : (select_connect_backend_servers): Selected RUNNING SLAVE in 192.168.137.22:3306
2016-11-03 23:13:46.908 info : (select_connect_backend_servers): Selected RUNNING SLAVE in 192.168.137.23:3306
2016-11-03 23:13:46.908 info : (session_alloc): Started Read-Write Service client session [0] for 'HH' from 192.168.137.11
2016-11-03 23:13:46.909 [9] info : (route_single_stmt): > Autocommit: [enabled], trx is [not open], cmd: COM_QUERY, type: QUERY_TYPE_READ|QUERY_TYPE_SYSVAR_READ, stmt: select @@version_comment limit 1
2016-11-03 23:13:46.909 [9] info : (route_single_stmt): Route query to master 192.168.137.21:3306 <
2016-11-03 23:13:46.922 [9] info : (route_single_stmt): > Autocommit: [enabled], trx is [not open], cmd: COM_QUERY, type: QUERY_TYPE_READ, stmt: select USER()
2016-11-03 23:13:46.922 [9] info : (route_single_stmt): Route query to slave 192.168.137.22:3306 <
# 执行 SELECT * FROM test.t1 语句被路由到 192.168.137.22:3306[server2]中的日志
2016-11-03 23:15:02.618 [9] info : (route_single_stmt): > Autocommit: [enabled], trx is [not open], cmd: COM_QUERY, type: QUERY_TYPE_READ, stmt: SELECT * FROM test.t1
2016-11-03 23:15:02.618 [9] info : (route_single_stmt): Route query to slave 192.168.137.22:3306 <
# 执行 INSERT INTO test.t1 VALUES(NULL, 'HH4', 4) 语句被路由到 192.168.137.21:3306[server1]中的日志
2016-11-03 23:17:02.716 [9] info : (route_single_stmt): > Autocommit: [enabled], trx is [not open], cmd: COM_QUERY, type: QUERY_TYPE_WRITE, stmt: INSERT INTO test.t1 VALUES(NULL, 'HH4', 4)
2016-11-03 23:17:02.716 [9] info : (route_single_stmt): Route query to master 192.168.137.21:3306 <
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上面是最基本的读写分离操作
重点参数说明与演示
有许多刚刚搭建Maxscale的朋友会问到为什么我的select总是落在Master上,影响比较大的参数有两个,如下:
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# 监控主从复制延迟，可用后续指定router service的(配置此参数请求会永远落在 master)
detect_replication_lag=true
# 允许主从最大间隔(s).有些朋友在做压力测试的是会说SELECT 会打在Master,多半是这个参数
max_slave_replication_lag=3600
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- detect_replication_lag=true 时的现象
执行 SELECT 语句
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HH@192.168.137.11 11:24:59 [(none)]>SELECT * FROM test.t1;
+----+------+-----+
| id | name | age |
+----+------+-----+
| 1 | HH1 | 1 |
| 2 | HH2 | 2 |
| 3 | HH3 | 3 |
| 4 | HH4 | 4 |
+----+------+-----+
4 rows in set (0.00 sec)
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查看路由的日志
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# 该查询落在了Master(192.168.137.21:3306)[server1]上了
2016-11-03 23:25:04.364 [7] info : (route_single_stmt): > Autocommit: [enabled], trx is [not open], cmd: COM_QUERY, type: QUERY_TYPE_READ, stmt: SELECT * FROM test.t1
2016-11-03 23:25:04.364 [7] info : (route_single_stmt): Route query to master 192.168.137.21:3306 <
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所以我的配置是将 detect_replication_lag=true 给注释了也就是用默认值false.
关于 max_slave_replication_lag 这个参数我就不演示了, 因为涉及到了使用 sysbench 等压力工具不在本文范畴, 有兴趣的自己玩玩, 这边就说说该参数的意义。
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