顾名思义, 在mysql负载均衡中有多种方式, 本人愚钝,只了解驱动中间件和mysql_proxy两种方式, 对于驱动,利用的是ReplicationDriver,具体请看远哥的这篇文章: MySQL读写分离又一好办法 使用 com.mysql.jdbc.ReplicationDriver
本次我要实现利用的方式是: mysql_proxy
下面进入主题
mysql_proxy:192.168.99.55
master:192.168.99.61
slave:192.168.99.62
1.安装mysql_proxy
tar -zxvf mysql-proxy-0.8.4-linux-rhel5-x86-64bit.tar.gz -C /usr/local cd /usr/local mv mysql-proxy-0.8.4-linux-rhel5-x86-64bit mysql-proxy
下面是需要的依赖
gcc* gcc-c++* autoconf* automake* zlib* libxml* ncurses-devel* libmcrypt* libtool* flex* pkgconfig* libevent* glib* readline-devel
2.添加代理用户
useradd -r mysql-proxy
3.sysv服务脚本mysql_proxy
这个脚本放置的位置是：/etc/init.d
记得授权，chmod +x /etc/init.d/mysql_proxy
这个脚本是用来做快捷启动的。
#!/bin/bash
#
# mysql-proxy This script starts and stops the mysql-proxy daemon
#
# chkconfig: - 78 30
# processname: mysql-proxy
# description: mysql-proxy is a proxy daemon for mysql
# Source function library.
. /etc/rc.d/init.d/functions
prog="/usr/local/mysql-proxy/bin/mysql-proxy"
# Source networking configuration.
if [ -f /etc/sysconfig/network ]; then
. /etc/sysconfig/network
fi
# Check that networking is up.
[ ${NETWORKING} = "no" ] && exit 0
# Set default mysql-proxy configuration.
ADMIN_USER="admin"
ADMIN_PASSWD="admin"
ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua"
PROXY_OPTIONS="--daemon"
PROXY_PID=/var/run/mysql-proxy.pid
PROXY_USER="mysql-proxy"
# Source mysql-proxy configuration.
if [ -f /etc/sysconfig/mysql-proxy ]; then
. /etc/sysconfig/mysql-proxy
fi
RETVAL=0
start() {
echo -n $"Starting $prog: "
daemon $prog $PROXY_OPTIONS --pid-file=$PROXY_PID --proxy-address="$PROXY_ADDRESS" --user=$PROXY_USER --admin-username="$ADMIN_USER" --admin-lua-script="$ADMIN_LUA_SCRIPT" --admin-password="$ADMIN_PASSWORD"
RETVAL=$?
echo
if [ $RETVAL -eq 0 ]; then
touch /var/lock/subsys/mysql-proxy
fi
}
stop() {
echo -n $"Stopping $prog: "
killproc -p $PROXY_PID -d 3 $prog
RETVAL=$?
echo
if [ $RETVAL -eq 0 ]; then
rm -f /var/lock/subsys/mysql-proxy
rm -f $PROXY_PID
fi
}
# See how we were called.
case "$1" in
start)
start
;;
stop)
stop
;;
restart)
stop
start
;;
condrestart|try-restart)
if status -p $PROXY_PIDFILE $prog >&/dev/null; then
stop
start
fi
;;
status)
status -p $PROXY_PID $prog
;;
*)
echo "Usage: $0 {start|stop|restart|reload|status|condrestart|try-restart}"
RETVAL=1
;;
esac
exit $RETVAL
4.为服务脚本提供配置文件mysql_proxy
这个脚本放在的位置是:/etc/sysconfig(我是根据上面服务脚本的位置放的, 喜欢放在别处的地方可以自行修改)。
# Options for mysql-proxy ADMIN_USER="admin" ADMIN_PASSWORD="admin" ADMIN_ADDRESS="" ADMIN_LUA_SCRIPT="/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua" PROXY_ADDRESS="" PROXY_USER="mysql-proxy" PROXY_OPTIONS="--daemon --log-level=info --log-use-syslog --plugins=proxy --plugins=admin --proxy-backend-addresses=192.168.99.61:3306
--proxy-read-only-backend-addresses=192.168.99.62:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua"
5.创建admin.lua
这个脚本放置的位置是:/usr/local/mysql-proxy/share/doc/mysql-proxy
--[[ $%BEGINLICENSE%$
Copyright (c) 2007, 2012, Oracle and/or its affiliates. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; version 2 of the
License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
02110-1301 USA
$%ENDLICENSE%$ --]]
function set_error(errmsg)
proxy.response = {
type = proxy.MYSQLD_PACKET_ERR,
errmsg = errmsg or "error"
}
end
function read_query(packet)
if packet:byte() ~= proxy.COM_QUERY then
set_error("[admin] we only handle text-based queries (COM_QUERY)")
return proxy.PROXY_SEND_RESULT
end
local query = packet:sub(2)
local rows = { }
local fields = { }
if query:lower() == "select * from backends" then
fields = {
{ name = "backend_ndx",
type = proxy.MYSQL_TYPE_LONG },
{ name = "address",
type = proxy.MYSQL_TYPE_STRING },
{ name = "state",
type = proxy.MYSQL_TYPE_STRING },
{ name = "type",
type = proxy.MYSQL_TYPE_STRING },
{ name = "uuid",
type = proxy.MYSQL_TYPE_STRING },
{ name = "connected_clients",
type = proxy.MYSQL_TYPE_LONG },
}
for i = 1, #proxy.global.backends do
local states = {
"unknown",
"up",
"down"
}
local types = {
"unknown",
"rw",
"ro"
}
local b = proxy.global.backends[i]
rows[#rows + 1] = {
i,
b.dst.name, -- configured backend address
states[b.state + 1], -- the C-id is pushed down starting at 0
types[b.type + 1], -- the C-id is pushed down starting at 0
b.uuid, -- the MySQL Server's UUID if it is managed
b.connected_clients -- currently connected clients
}
end
elseif query:lower() == "select * from help" then
fields = {
{ name = "command",
type = proxy.MYSQL_TYPE_STRING },
{ name = "description",
type = proxy.MYSQL_TYPE_STRING },
}
rows[#rows + 1] = { "SELECT * FROM help", "shows this help" }
rows[#rows + 1] = { "SELECT * FROM backends", "lists the backends and their state" }
else
set_error("use 'SELECT * FROM help' to see the supported commands")
return proxy.PROXY_SEND_RESULT
end
proxy.response = {
type = proxy.MYSQLD_PACKET_OK,
resultset = {
fields = fields,
rows = rows
}
}
return proxy.PROXY_SEND_RESULT
end
6.修改rw-splitting.lua
修改的是min_idle_connections和max_idle_connections的值,都等于1
local commands = require("proxy.commands")
local tokenizer = require("proxy.tokenizer")
local lb = require("proxy.balance")
local auto_config = require("proxy.auto-config")
--- config
--
-- connection pool
if not proxy.global.config.rwsplit then
proxy.global.config.rwsplit = {
min_idle_connections = 1,
max_idle_connections = 1,
is_debug = false
}
end
7.测试mysql_proxy
7.1启动mysql_proxy
service mysql_proxy start
7.2端口进程状态
进程
ps aux | grep mysql-proxy root 14230 0.0 0.0 103244 836 pts/0 S+ 11:25 0:00 grep mysql-proxy 496 28239 0.0 0.0 45772 2104 ? S Dec04 0:03 /usr/local/mysql-proxy/libexec/mysql-proxy --daemon --log-level=info --log-use-syslog --plugins=proxy --plugins=admin --proxy-backend-addresses=192.168.75.61:3306 --proxy-read-only-backend-addresses=192.168.75.62:3306 --proxy-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/rw-splitting.lua --pid-file=/var/run/mysql-proxy.pid --proxy-address= --user=mysql-proxy --admin-username=admin --admin-lua-script=/usr/local/mysql-proxy/share/doc/mysql-proxy/admin.lua --admin-password=admin
端口
netstat -tlnp | grep mysql-proxy tcp 0 0 0.0.0.0:4041 0.0.0.0:* LISTEN 28239/mysql-proxy tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 28239/mysql-proxy
看到上面, 端口有4041与3306, 这两个端口都是关键所在,下面将进行解题。
7.3登录mysql_proxy
随便找一台有mysql客户端的机器登录到mysql_proxy192.168.99.55(也可以在99.55上面安装mysql客户端, 我是在别的机器连得), 这个登录使用的账号密码还记得把?它就是脚本中指定的账号密码,admin:admin
mysql -u admin -p -h 192.168.99.55 --port=4041
必须指定端口, 不然跑的是3306
7.4查询状态
7.4.1 select * from help
+------------------------+------------------------------------+ | command | description | +------------------------+------------------------------------+ | SELECT * FROM help | shows this help | | SELECT * FROM backends | lists the backends and their state | +------------------------+------------------------------------+ 2 rows in set (0.00 sec)
7.4.2 SELECT * FROM backends
+-------------+--------------------+-------+------+------+-------------------+ | backend_ndx | address | state | type | uuid | connected_clients | +-------------+--------------------+-------+------+------+-------------------+ | 1 | 192.168.99.61:3306 | down | rw | NULL | 0 | | 2 | 192.168.99.62:3306 | down | ro | NULL | 0 | +-------------+--------------------+-------+------+------+-------------------+ 2 rows in set (0.00 sec)
看到上面的信息, master99.61的type是rw(支持读写),slave99.62的type是ro(只读)
7.5抓包分析
在master上:
tcpdump -i eth0 -nn -XX ip dst 192.168.99.61 and tcp dst port 3306
在slave上:
tcpdump -i eth0 -nn -XX ip dst 192.168.99.62 and tcp dst port 3306
7.5.1主从分析
为了更明显操作结果, 停止主从
登录mysql_proxy
mysql -u admin -p -h 192.168.75.55 --port=3306
这次登录的是3306, 上面登录的是4041,请大家不要混淆。
至于3306与4041有什么不一样， 下面我解析一下， 4041就是查询读写分离的状态的， 3306无疑就是提供给外部的接口。
现在往test表插入一条数据
insert into test.testtest values(80,'80');
下面查询, 是查询不到的, 因为主从已经断开, 查的是往62跑, 写是写进61了, 只要把主从配置回来一切正常。
上面的抓包就是没操作一下都会有记录, 这次很明显看出来读写分析所跑的机器。
进行写时, master抓到的包是:
14:25:28.835455 IP 192.168.99.55.45648 > 192.168.99.61.3306: Flags [P.], seq 2082548409:2082548453, ack 3795613073, win 173, options [nop,nop,TS val 2915927263 ecr 2948974813], length 44
0x0000: 0050 5689 cba6 0050 5689 9616 0800 4508 .PV....PV.....E.
0x0010: 0060 994f 4000 4006 897b c0a8 4b37 c0a8 .`.O@.@..{..K7..
0x0020: 4b3d b250 0cea 7c21 2ab9 e23c 7591 8018 K=.P..|!*..<u...
0x0030: 00ad eed3 0000 0101 080a adcd 84df afc5 ................
0x0040: c8dd 2800 0000 0369 6e73 6572 7420 696e ..(....insert.in
0x0050: 746f 2074 6573 742e 7465 7374 7465 7374 to.test.testtest
0x0060: 2076 616c 7565 7328 322c 2732 2729 .values(2,'2')
14:25:28.836543 IP 192.168.99.55.45648 > 192.168.99.61.3306: Flags [.], ack 12, win 173, options [nop,nop,TS val 2915927264 ecr 2949040785], length 0
0x0000: 0050 5689 cba6 0050 5689 9616 0800 4508 .PV....PV.....E.
0x0010: 0034 9950 4000 4006 89a6 c0a8 4b37 c0a8 .4.P@.@.....K7..
0x0020: 4b3d b250 0cea 7c21 2ae5 e23c 759c 8010 K=.P..|!*..<u...
0x0030: 00ad f329 0000 0101 080a adcd 84e0 afc6 ...)............
slave此时的状态是:
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
进行读时, slave的状态是:
15:00:36.252068 IP 192.168.99.55.40191 > 192.168.99.62.3306: Flags [P.], seq 853416170:853416202, ack 2118301929, win 184, options [nop,nop,TS val 2915944710 ecr 2911691799], length 32
0x0000: 0050 5689 a328 0050 5689 9616 0800 4508 .PV..(.PV.....E.
0x0010: 0054 7caa 4000 4006 a62b c0a8 4b37 c0a8 .T|.@.@..+..K7..
0x0020: 4b3e 9cff 0cea 32de 18ea 7e42 b8e9 8018 K>....2...~B....
0x0030: 00b8 0093 0000 0101 080a adcd c906 ad8c ................
0x0040: e417 1c00 0000 0373 656c 6563 7420 2a20 .......select.*.
0x0050: 6672 6f6d 2074 6573 742e 7465 7374 7465 from.test.testte
0x0060: 7374 st
15:00:36.253339 IP 192.168.99.55.40191 > 192.168.99.62.3306: Flags [.], ack 144, win 223, options [nop,nop,TS val 2915944712 ecr 2912255989], length 0
0x0000: 0050 5689 a328 0050 5689 9616 0800 4508 .PV..(.PV.....E.
0x0010: 0034 7cab 4000 4006 a64a c0a8 4b37 c0a8 .4|.@.@..J..K7..
0x0020: 4b3e 9cff 0cea 32de 190a 7e42 b978 8010 K>....2...~B.x..
0x0030: 00df 8c29 0000 0101 080a adcd c908 ad95 ...)............
0x0040: 7ff5 ..
最终拓扑
