Mysql（五）读写分离(mysql-proxy)

读写分离可以用很多软件实现：mysql-proxy 、MyCat 、Amoeba
在这里先演示proxy，其他下去自己看
先看官网，官网没有el7版本的mysql-proxy，所以还是用6的

实验前提：用server3来做proxy，1和2一个读一个写
做以下实验之前，先做好server1和server2的gtid主从复制

server3上：

先关闭之前的mysql，因为proxy也用3306端口
tar zxf mysql-proxy-0.8.5-linux-el6-x86-64bit.tar.gz -C /usr/local
cd /usr/local/
ln -s mysql-proxy-0.8.5-linux-el6-x86-64bit/ mysql-proxy    #软链接便于访问

关于帮助文件
cd /usr/local/mysql-proxy/bin
./mysql-proxy --help    ##查看帮助
./mysql-proxy --help-proxy    ##查看proxy的帮助
./mysql-proxy --help-all    ##查看所有帮助

cd /usr/local/mysql-proxy
mkdir conf    ##建立配置文件目录

#编辑配置文件（自己手动新建）
在新创建的目录下：

vim mysql-proxy.conf    

[mysql-proxy]
proxy-address=0.0.0.0:3306
proxy-backend-addresses=172.25.136.1:3306
proxy-read-only-backend-addresses=172.25.136.2:3306
proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua
pid-file=/usr/local/mysql-proxy/log/mysql-proxy.pid
plugins=proxy
log-file=/usr/local/mysql-proxy/log/mysql-proxy.log
log-level=debug
keepalive=true
daemon=true

#创建日志目录

mkdir /usr/local/mysql-proxy/log

#修改lua脚本

min_idle_connections = 1,    ##把原来的4和8改为1和2，默认超过4个连接才会启动读写分离，改为1个好测试
max_idle_connections = 2,

#启动mysql-proxy

/usr/local/mysql-proxy/bin/mysql-proxy --defaults-file=/usr/local/mysql-proxy/conf/mysql-proxy.conf

启动报错：
 

2019-11-1 14:15:04: (critical) mysql-proxy-cli.c:326: loading config from '/usr/local/mysql-proxy/conf/mysql-proxy.conf' failed: permissions of /usr/local/mysql-proxy/conf/mysql-proxy.conf aren't secure (0660 or stricter required)
2019-11-1 14:15:04: (message) Initiating shutdown, requested from mysql-proxy-cli.c:328
2019-11-1 14:15:04: (message) shutting down normally, exit code is: 1

原因：配置文件权限过大
 

chmod 660 /usr/local/mysql-proxy/conf/mysql-proxy.conf

再启动，正常

#查看日志，看到两个节点都加进来了

cat /usr/local/mysql-proxy/log/mysql-proxy.log

查看结果：

 (message) chassis-unix-daemon.c:136: [angel] we try to keep PID=2521 alive
 (debug) chassis-unix-daemon.c:157: waiting for 2521
(debug) chassis-unix-daemon.c:121: we are the child: 2521
(critical) plugin proxy 0.8.5 started
 (debug) max open file-descriptors = 1024
(message) proxy listening on port 0.0.0.0:3306
(message) added read/write backend: 172.25.136.1:3306
(message) added read-only backend: 172.25.136.2:3306

#在server1上授权新用户读写权限

mysql> grant insert,update,select on *.* to wsp@'%' identified by 'Wsp+123ld';

mysql> flush privileges;

mysql> use westos;
Database changed
mysql> create table usertb (
    -> username varchar(10) not null,
    -> password varchar(15) not null);

mysql> desc usertb;

#在物理机上打开一个shell来连接数据库

[kiosk@foundation58 ~]$ mysql -h 172.25.58.3 -uwsp -pWsp+123ld

#然后在server3上看到连接已经建立

[root@server3 log]# lsof -i:3306
COMMAND    PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
mysql-pro 2521 root   10u  IPv4  28318      0t0  TCP *:mysql (LISTEN)
mysql-pro 2521 root   11u  IPv4  28362      0t0  TCP server3:mysql->foundation0.ilt.example.com:55716 (ESTABLISHED)
mysql-pro 2521 root   12u  IPv4  28363      0t0  TCP server3:47376->server1:mysql (ESTABLISHED)

#在物理机上再打开一个shell来连接数据库
#再到server3上查看
 

[root@server3 log]# lsof -i:3306
COMMAND    PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
mysql-pro 2521 root   10u  IPv4  28318      0t0  TCP *:mysql (LISTEN)
mysql-pro 2521 root   11u  IPv4  28362      0t0  TCP server3:mysql->foundation0.ilt.example.com:55716 (ESTABLISHED)
mysql-pro 2521 root   12u  IPv4  28363      0t0  TCP server3:47376->server1:mysql (ESTABLISHED)
mysql-pro 2521 root   13u  IPv4  28709      0t0  TCP server3:mysql->foundation0.ilt.example.com:55722 (ESTABLISHED)
mysql-pro 2521 root   14u  IPv4  28710      0t0  TCP server3:47382->server1:mysql (ESTABLISHED)

'发现两次连接都指向server1'
#在物理机上再打开一个shell来连接数据库
#再到server3上查看

[root@server3 log]# lsof -i:3306
COMMAND    PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
mysql-pro 2521 root   10u  IPv4  28318      0t0  TCP *:mysql (LISTEN)
mysql-pro 2521 root   11u  IPv4  28362      0t0  TCP server3:mysql->foundation0.ilt.example.com:55716 (ESTABLISHED)
mysql-pro 2521 root   12u  IPv4  28363      0t0  TCP server3:47376->server1:mysql (ESTABLISHED)
mysql-pro 2521 root   13u  IPv4  28709      0t0  TCP server3:mysql->foundation0.ilt.example.com:55722 (ESTABLISHED)
mysql-pro 2521 root   14u  IPv4  28710      0t0  TCP server3:47382->server1:mysql (ESTABLISHED)
mysql-pro 2521 root   15u  IPv4  28769      0t0  TCP server3:mysql->foundation0.ilt.example.com:55726 (ESTABLISHED)
mysql-pro 2521 root   16u  IPv4  28770      0t0  TCP server3:55914->server2:mysql (ESTABLISHED)

'这次连接到了server2，说明读写分离启用'

#测试读写分离
在物理机上插入数据：
 

MySQL [(none)]> use westos
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A
MySQL [westos]> insert into usertb values('user1','123');
MySQL [westos]> select * from usertb;
+----------+----------+
| username | password |
+----------+----------+
| user1    | 123      |
+----------+----------+
1 row in set (0.00 sec)

现在到server2上关闭复制
mysql> stop slave;
这时再在物理机上插入数据

MySQL [westos]> insert into usertb values ('user4','123');
Query OK, 1 row affected (0.01 sec)

MySQL [westos]> select * from usertb;
+----------+----------+
| username | password |
+----------+----------+
| user1    | 123      |
| user2    | 123      |
+----------+----------+
2 rows in set (0.00 sec)

发现插入的数据看不到，但是在server1上可以看到，这就说明了它在读的时候读的是server2上的数据，而写操作却写在了server1上