mysql主从复制与lvs+keepalived实现负载高可用
目录
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
最近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，可以提高服务器的使用效率，也可以提高提高维护效率。同时应用的效率也会有一定的提升，如果改造需要应用修改读取的ip地址与写入的ip地址，改造起来还算容易。
2、原理
2.1、概要介绍
如果将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，其主要作用是检测web服务器的状 态，如果某台web服务器故障，Keepalived将检测到并将其从系统中剔除，当该web服务器工作正常后Keepalived自动将其加入到服务器 群中，这些工作全部自动完成，而不需要人工干预，只需要人工修复故障的web服务器即可。
2.2、工作原理
Keepalived基于VRRP协议来实现高可用解决方案，利用其避免单点故障，通常这个解决方案中，至少有2台服务器运行Keepalived，即一 台为MASTER，另一台为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，则认为 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给某台服务器，如果不痛，则认为其故障，并从服务器群中剔除。4层机理是检测TCP端口号状态来判断某台服务器是否故障，如果故障，则从服务器群中剔除。5层机理是根据用户的设定检查某个服务器应用程序是否正常运行，如果不正常，则从服务器群中剔除。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)，采用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
任何一台主机宕机都不会影响对外提供服务（读写vip可以浮动），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：任意，只要能访问以上三个IP即可
3.2、架构图
具体架构图如下：
3.3、设计原理(异常情况)
1、 服务器A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，其他不变
具体实现后的效果
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 可以根据需要进行安装，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)说明安装成功
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
添加如下内容：
server-id = 1 ##master ID
binlog-do-db = ppl ##允许同步的库
binlog-ignore-db = mysql ##忽略同步的库，也就是不能同步的库
##配置文件中还需开启log-bin，例如log-bin = mysql-bin
mysql –uroot –p
以下内容在mysql中执行
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);
返回一表格如下，记住File的内容，等下slave的配置中要用到
Slave的配置
vi /etc/my.cnf
添加如下内容：
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 ##同步的同时，也记录自己的binlog日志，如果还有台slave是通过这台机器进行同步，那需要增加此项，
#skip-slave-start ##启动时不自动开启slave进程
#read-only ##将库设为只读模式，只能从master同步，不能直接写入（避免自增键值冲突）
mysql –uroot –p
以下内容在mysql中执行
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，如果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
将这两个参数前边的 # 去掉，重启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 主库可以查看ip a
[root@rac3 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,UP,LOWER_UP> 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: <NOARP> 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: <LOOPBACK,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,UP,LOWER_UP> 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: <BROADCAST,MULTICAST,UP,LOWER_UP> 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: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
发现210.174 读的vip 在主备机上都可以看到
210.173 写入vip在主上才能看到
后续多台实验进行中，敬请等待
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