mysql主从复制与lvs+keepalived实现负载高可用

文件夹

1、前言    4

2、原理    4

2.1、概要介绍    4

2.2、工作原理    4

2.3、实际作用    4

3方案    4

3.1、环境    4

3.2、架构图    5

3.3、设计原理    6

4、相关软件安装    6

4、配置mysql的主从    7

5、通过lvs+keepalived实现负载与热备，并实现读写分离    8

1、前言

近期研究了下高可用的东西，这里总结一下mysql主从复制读写分离度的高可用方案，能够提高server的使用效率，也能够提高提高维护效率。同一时候应用的效率也会有一定的提升，假设改造须要应用改动读取的ip地址与写入的ip地址，改造起来还算easy。

2、原理

2.1、概要介绍

假设将TCP/IP划分为5层，则Keepalived就是一个类似于3~5层交换机制的软件，具有3~5层交换功能，其主要作用是检測webserver的状 态，假设某台webserver故障，Keepalived将检測到并将其从系统中剔除，当该webserver工作正常后Keepalived自己主动将其增加到server 群中，这些工作所有自己主动完毕，而不须要人工干预，仅仅须要人工修复故障的webserver就可以。

2.2、工作原理

Keepalived基于VRRP协议来实现高可用解决方式，利用其避免单点故障，通常这个解决方式中，至少有2台server执行Keepalived，即一 台为MASTER，还有一台为BACKUP，但对外表现为一个虚拟IP，MASTER会发送特定消息给BACKUP，当BACKUP收不到该消息时，则觉得 MASTER故障了，BACKUP会接管虚拟IP，继续提供服务，从而保证了高可用性，3层机理是发送ICMP数据包即PING给某台server，假设不痛，则觉得其故障，并从server群中剔除。4层机理是检測TCPport号状态来推断某台server是否故障，假设故障，则从server群中剔除。5层机理是依据用户的设定检查某个server应用程序是否正常执行，假设不正常，则从server群中剔除。3、

2.3、实际作用

Keepalived+lvs主要用作RealServer的健康检查，以及负载均衡设备MASTER和BACKUP之间failover的实现。

3方案

本案例先使用两台linux做双机MASTER-SLAVE高可用,实现都写分离,用于提高查询性能)，採用MYSQL5.6.x的半同步实现数据复制和同步，使用keepalived来监控MYSQL和提供读写VIP浮动。Keepalived在这里主要用作RealServer的健康状态检查以及LoadBalance主机和BackUP主机之间failover的实现

不论什么一台主机宕机都不会影响对外提供服务(读写vip能够浮动)，保持服务的高可用。

3.1、环境

主机A：192.168.150.171

主机B：192.168.150.172

W-VIP：192.168.150.173  (负责写入)

R-VIP：192.168.150.174   (负责读取)

Client：随意，仅仅要能訪问以上三个IP就可以

3.2、架构图

详细架构图例如以下：

3.3、设计原理(异常情况)

1、    serverA和B，通过mysql的slave进程是用binlog同步数据。

2、    通过keepalived启用两个虚IP：W-VIP/R-VIP，一个负责写入，一个负责读取，实现读写分离。

3、    A和B都存在时，W-VIP下将请求转发至主机A，R-VIP将请求转发给A和B，实现负载均衡。

4、    当主机A异常时，B接管服务，W-VIP/R-VIP此时漂到了主机B上，此时这两个虚IP下都是主机B，实现高可用

5、    当主机B异常时，R-VIP会将B踢出，其它不变

详细实现后的效果

正常状态

Prot LocalAddress:Port Scheduler Flags

-> RemoteAddress:Port           Forward Weight ActiveConn InActConn

TCP  192.168.150.173:3306 wrr persistent 60

-> 192.168.150.171:3306           Local   3      0          0

TCP  192.168.150.174:3306 wrr persistent 60

-> 192.168.150.172:3306           Route   3      0          0

-> 192.168.150.171:3306           Local   1      0          0

A故障后，B的状态

Prot LocalAddress:Port Scheduler Flags

-> RemoteAddress:Port           Forward Weight ActiveConn InActConn

TCP  192.168.150.173:3306 wrr persistent 60

-> 192.168.150.172:3306           Local   3      0          0

TCP  192.168.150.174:3306 wrr persistent 60

-> 192.168.150.172:3306           Local   3      0          0

架构图

4、相关软件安装

1、    mysql  能够依据须要进行安装，此处省略

2、    lvs+keepalived的安装

关联lvs与keepalived的ipvs所需的内核信息

ln -s /usr/src/kernels/2.6.18-194.el5-x86_64/ /usr/src/linux

安装lvs

下载：wget http://www.linuxvirtualserver.org/software/kernel-2.6/ipvsadm-1.24.tar.gz

tar -zxvf ipvsadm-1.24.tar.gz

cd tar -zxvf ipvsadm-1.24

make

make install

yum install ipv* 安装

验证

ipvsadm –v

ipvsadm v1.24 2003/06/07 (compiled with getopt_long and IPVS v1.2.0)说明成功安装

安装keepalived

tar –zxvf keepalived-1.2.12.tar.gz

cd keepalived-1.2.12

./configure --prefix=/usr/local/keepalived/

make

make install

ln -s /usr/local/keepalived/etc/keepalived /etc/

ln -s /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/

ln -s /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

ln -s /usr/local/keepalived/bin/genhash /bin/

ln -s /usr/local/keepalived/sbin/keepalived /sbin/

configure时注意Use IPVS Framework、IPVS sync daemon support 、Use VRRP Framework要返回yes，否则无法关联ipvs功能

4、配置mysql的主从

Master(210.171)的配置

vi /etc/my.cnf

加入例如以下内容：

server-id = 1    ##master ID

binlog-do-db = ppl  ##同意同步的库

binlog-ignore-db = mysql  ##忽略同步的库，也就是不能同步的库

##配置文件里还需开启log-bin，比如log-bin = mysql-bin

mysql –uroot –p

下面内容在mysql中运行

mysql> grant replication slave on *.* to ‘repdb01’@’%’ identified by '123456';

mysql>create database db01;

mysql>flush logs;

mysql>show master status;

mysql>use db01

mysql> create table test(name char);

返回一表格例如以下，记住File的内容，等下slave的配置中要用到

Slave的配置

vi /etc/my.cnf

加入例如以下内容：

server-id = 2  ##slave ID

master-host = 192.168.150.171  ##指定master的地址

master-user = repdb01    ##同步所用的账号

master-password = 123456   ##同步所用的密码

master-port = 3306     ##master上mysql的端口

replicate-do-db = db01   ##要同步的库名

replicate-ignore-db = mysql  ##忽略的库名

slave-skip-errors = 1062   ##当同步异常时，那些错误跳过，本例为1062错误

#log-slave-updates  ##同步的同一时候，也记录自己的binlog日志，假设还有台slave是通过这台机器进行同步，那须要添加此项，

#skip-slave-start  ##启动时不自己主动开启slave进程

#read-only  ##将库设为仅仅读模式，仅仅能从master同步，不能直接写入(避免自增键值冲突)

mysql –uroot –p

下面内容在mysql中运行

mysql>create database db01;

mysql>change master to master_log_file=’mysql-bin.000007’,master_log=106;

mysql>slave start;

mysql>show slave status \G

在返回值中查看，假设slave_IO_Runing与slave_SQL_Runing的值都为Yes说明同步成功

5、通过lvs+keepalived实现负载与热备，并实现读写分离

Master上的配置

vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

router_id MySQL-HA

}

vrrp_instance VI_1 {

state BACKUP

interface eth0

virtual_router_id 90

priority 100

advert_int 1

notify_master "/usr/local/mysql/bin/remove_slave.sh"

nopreempt

authentication {

auth_type PASS

auth_pass abcd1234

}

virtual_ipaddress {

192.168.150.173 label eth0:1

192.168.150.174 label eth0:2

}

}

virtual_server 192.168.150.173 3306 {

delay_loop 2

lb_algo wrr

lb_kind DR

persistence_timeout 60

protocol TCP

real_server 192.168.150.171 3306 {

weight 3

notify_down /usr/local/mysql/bin/mysql.sh

TCP_CHECK {

connect_timeout 10

nb_get_retry 3

delay_before_retry 3

connect_port 3306

}

}

}

virtual_server 192.168.150.174 3306 {

delay_loop 2

lb_algo wrr

lb_kind DR

persistence_timeout 60

protocol TCP

real_server 192.168.150.171 3306 {

weight 1

notify_down /usr/local/mysql/bin/mysql.sh

TCP_CHECK {

connect_timeout 10

nb_get_retry 3

delay_before_retry 3

connect_port 3306

}

}

real_server 192.168.150.172 3306 {

weight 3

TCP_CHECK {

connect_timeout 10

nb_get_retry 3

delay_before_retry 3

connect_port 3306

}

}

}

vi /usr/local/mysql/bin/remove_slave.sh

#!/bin/bash

user=root

password=123456

log=/root/mysqllog/remove_slave.log

#--------------------------------------------------------------------------------------

echo "`date`" >> $log

/usr/bin/mysql -u$user -p$password -e "set global read_only=OFF;reset master;stop slave;change master to master_host='localhost';" >> $log

/bin/sed -i 's#read-only#\#read-only#' /etc/my.cnf

chomd 755 /usr/local/mysql/bin/remove_slave.sh

vi /usr/local/mysql/bin/mysql.sh

#!/bin/bash

/etc/init.d/keepalived stop

Slave上的配置

vi /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

router_id MySQL-HA

}

vrrp_instance VI_1 {

state BACKUP

interface eth0

virtual_router_id 90

priority 99

advert_int 1

notify_master "/usr/local/mysql/bin/remove_slave.sh"

authentication {

auth_type PASS

auth_pass ppl.com

}

virtual_ipaddress {

192.168.150.173 label eth0:1

192.168.150.174 label eth0:2

}

}

virtual_server 192.168.150.173 3306 {

delay_loop 2

lb_algo wrr

lb_kind DR

persistence_timeout 60

protocol TCP

real_server 192.168.150.172 3306 {

weight 3

notify_down /usr/local/mysql/bin/mysql.sh

TCP_CHECK {

connect_timeout 10

nb_get_retry 3

delay_before_retry 3

connect_port 3306

}

}

}

virtual_server 192.168.150.174 3306 {

delay_loop 2

lb_algo wrr

lb_kind DR

persistence_timeout 60

protocol TCP

real_server 192.168.150.172 3306 {

weight 3

notify_down /usr/local/mysql/bin/mysql.sh

TCP_CHECK {

connect_timeout 10

nb_get_retry 3

delay_before_retry 3

connect_port 3306

}

}

#    real_server 192.168.150.172 3306 {

#        weight 3

#        TCP_CHECK {

#            connect_timeout 10

#            nb_get_retry 3

#            delay_before_retry 3

#            connect_port 3306

#        }

#    }

}

vi /usr/local/mysql/bin/remove_slave.sh

#!/bin/bash

user=root

password=123456

log=/root/mysqllog/remove_slave.log

#--------------------------------------------------------------------------------------

echo "`date`" >> $log

/usr/bin/mysql -u$user -p$password -e "set global read_only=OFF;reset master;stop slave;change master to master_host='localhost';" >> $log

/bin/sed -i 's#read-only#\#read-only#' /etc/my.cnf

chomd 755 /usr/local/mysql/bin/remove_slave.sh

vi /usr/local/mysql/bin/mysql.sh

#!/bin/bash

/etc/init.d/keepalived stop

vi /usr/local/keepalived/bin/lvs-rs.sh

#!/bin/bash

WEB_VIP=192.168.150.174

. /etc/rc.d/init.d/functions

case "$1" in

start)

ifconfig lo:0 $WEB_VIP netmask 255.255.255.255 broadcast $WEB_VIP

/sbin/route add -host $WEB_VIP dev lo:0

echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore

echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce

echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore

echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce

sysctl -p >/dev/null 2>&1

echo "RealServer Start OK"

;;

stop)

ifconfig lo:0 down

route del $WEB_VIP >/dev/null 2>&1

echo "0" >/proc/sys/net/ipv4/conf/lo/arp_ignore

echo "0" >/proc/sys/net/ipv4/conf/lo/arp_announce

echo "0" >/proc/sys/net/ipv4/conf/all/arp_ignore

echo "0" >/proc/sys/net/ipv4/conf/all/arp_announce

echo "RealServer Stoped"

;;

status)

# Status of LVS-DR real server.

islothere=`/sbin/ifconfig lo:0 | grep $WEB_VIP`

isrothere=`netstat -rn | grep "lo:0" | grep $web_VIP`

if [ ! "$islothere" -o ! "isrothere" ];then

# Either the route or the lo:0 device

# not found.

echo "LVS-DR real server Stopped."

else

echo "LVS-DR Running."

fi

;;

*)

# Invalid entry.

echo "$0: Usage: $0 {start|status|stop}"

exit 1

;;

esac

exit 0

chmod 755 /usr/local/keepalived/bin/lvs-rs.sh

echo “/usr/local/keepalived/bin/lvs-rs.sh start” >>/etc/rc.local

vi /etc/my.cnf

将这两个參数前边的 # 去掉，重新启动mysql

#skip-slave-start

#read-only

登陆mysql，手动将slave进程启动

mysql>slave start;

先启动master上的keepalived，正常后再启动slave上的。

启动后 主库能够查看ip a

[root@rac3 ~]# ip a

1: lo: mtu 16436 qdisc noqueue

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

inet6 ::1/128 scope host

valid_lft forever preferred_lft forever

2: eth0: mtu 1500 qdisc pfifo_fast qlen 1000

link/ether 00:50:56:95:06:1f brd ff:ff:ff:ff:ff:ff

inet 192.168.150.171.171/24 brd 192.168.0.255 scope global eth0

inet 192.168.150.173/32 scope global eth0:1

inet 192.168.150.174/32 scope global eth0:2

inet6 fe80::250:56ff:fe95:61f/64 scope link

valid_lft forever preferred_lft forever

3: sit0: mtu 1480 qdisc noop

link/sit 0.0.0.0 brd 0.0.0.0

slave上查看

[root@rac1 keepalive]# ip a

1: lo: mtu 16436 qdisc noqueue

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

inet 192.168.150.174/32 brd 192.168.150.174 scope global lo:0

inet6 ::1/128 scope host

valid_lft forever preferred_lft forever

2: eth0: mtu 1500 qdisc pfifo_fast qlen 1000

link/ether 00:50:56:95:5e:b4 brd ff:ff:ff:ff:ff:ff

inet 192.168.150.188/24 brd 192.168.0.255 scope global eth0

inet 192.168.150.252/24 brd 192.168.0.255 scope global secondary eth0:1

inet 192.168.150.186/24 brd 192.168.0.255 scope global secondary eth0:4

inet6 fe80::250:56ff:fe95:5eb4/64 scope link

valid_lft forever preferred_lft forever

3: eth1: mtu 1500 qdisc pfifo_fast qlen 1000

link/ether 00:50:56:95:11:ba brd ff:ff:ff:ff:ff:ff

inet 10.10.10.188/24 brd 10.10.10.255 scope global eth1

inet 169.254.157.163/16 brd 169.254.255.255 scope global eth1:1

inet6 fe80::250:56ff:fe95:11ba/64 scope link

valid_lft forever preferred_lft forever

4: sit0: mtu 1480 qdisc noop

link/sit 0.0.0.0 brd 0.0.0.0

发现210.174 读的vip 在主备机上都能够看到

210.173 写入vip在主上才干看到

兴许多台实验进行中，敬请等待