Interesting things
我们之前的Keepalived+LVS单主模式，是只有一台lvs工作，这会造成资源浪费，可以采用双主结构，让两台lvs都进行工作，采用dns轮询方式，当用户访问域名通过dns轮询每天lvs，双主结构需要2个vip，这2个vip需要绑定域名。
同样，在每台lvs上安装keepalived软件，当keepalived检测到其中一个lvs宕机则将宕机的vip漂移到活动lvs上，当lvs恢复则vip又重新漂移回来。
附上我画的拓扑图
初始状态
其中一个主机宕机
主机恢复
image.png
所需环境
vip1 192.168.12.101
vip2 192.168.12.102
lvs_master1 192.168.12.12
lvs_master2 192.168.12.13
nginx1 192.168.12.2
nginx2 192.168.12.3
tomcat1 192.168.12.6
tomcat2 192.168.12.7
What did you do today
双主模式相比主从环境，区别在于：
1.DNS轮询。
2.LVS负载均衡层需要2个vip。比如192.168.12.12和192.168.12.13
3.后端的realServer上要绑定这2个vip到lo本地回环设备上
4.keepalived.conf的配置相比于上面的主从模式有所不同。
- 在192.168.12.2和192.168.12.3机器要绑定2个vip到本地回环口lo上(分别绑定lo:0和lo:1),所以需要在/etc/init.d/下编写double_master_lvsdr0和double_master_lvsdr1脚本，具体如下：
#!/bin/sh
VIP=192.168.12.101
. /etc/rc.d/init.d/functions
case "$1" in
start)
/sbin/ifconfig lo down
/sbin/ifconfig lo up
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
/sbin/sysctl -p >/dev/null 2>&1
/sbin/ifconfig lo:0 $VIP netmask 255.255.255.255 up
/sbin/route add -host $VIP dev lo:0
echo "LVS-DR real server starts successfully.\n"
;;
stop)
/sbin/ifconfig lo:0 down
/sbin/route del $VIP >/dev/null 2>&1
echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
echo "LVS-DR real server stopped.\n"
;;
status)
isLoOn=`/sbin/ifconfig lo:0 | grep "$VIP"`
isRoOn=`/bin/netstat -rn | grep "$VIP"`
if [ "$isLoON" == "" -a "$isRoOn" == "" ]; then
echo "LVS-DR real server has run yet."
else
echo "LVS-DR real server is running."
fi
exit 3
;;
*)
echo "Usage: $0 {start|stop|status}"
exit 1
esac
exit 0
#!/bin/sh
VIP=192.168.12.102
. /etc/rc.d/init.d/functions
case "$1" in
start)
/sbin/ifconfig lo down
/sbin/ifconfig lo up
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
/sbin/sysctl -p >/dev/null 2>&1
/sbin/ifconfig lo:1 $VIP netmask 255.255.255.255 up
/sbin/route add -host $VIP dev lo:1
echo "LVS-DR real server starts successfully.\n"
;;
stop)
/sbin/ifconfig lo:1 down
/sbin/route del $VIP >/dev/null 2>&1
echo "1" >/proc/sys/net/ipv4/conf/lo/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/lo/arp_announce
echo "1" >/proc/sys/net/ipv4/conf/all/arp_ignore
echo "2" >/proc/sys/net/ipv4/conf/all/arp_announce
echo "LVS-DR real server stopped.\n"
;;
status)
isLoOn=`/sbin/ifconfig lo:1 | grep "$VIP"`
isRoOn=`/bin/netstat -rn | grep "$VIP"`
if [ "$isLoON" == "" -a "$isRoOn" == "" ]; then
echo "LVS-DR real server has run yet."
else
echo "LVS-DR real server is running."
fi
exit 3
;;
*)
echo "Usage: $0 {start|stop|status}"
exit 1
esac
exit 0
- 将double_master_lvsdr0和double_master_lvsdr1设置开机启动
[root@localhost init.d]# chmod +x double_master_lvsdr0
[root@localhost init.d]# chmod +x double_master_lvsdr1
[root@localhost init.d]# echo "/etc/init.d/double_master_lvsdr0" >> /etc/rc.d/rc.local
[root@localhost init.d]# echo "/etc/init.d/double_master_lvsdr1" >> /etc/rc.d/rc.local
image.png
-
启动double_master_lvsdr0和double_master_lvsdr1脚本
image.png -
查看192.168.12.2和192.168.12.3，发现vip已经成功绑定到本地回环口lo上了。
 在lvs_master1和lvs_master2打开ip_forward路由转发功能
[root@localhost ~]# echo "1" > /proc/sys/net/ipv4/ip_forward
- lvs_master1上的keepalived.conf配置如下：
! Configuration File for keepalived
global_defs {
router_id LVS_MASTER
}
vrrp_script check_lvs {
script "/etc/keepalived/lvs_check.sh"
interval 2
weight -20
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
check_lvs
}
virtual_ipaddress {
192.168.12.101
}
}
vrrp_instance VI_2 {
state BACKUP
interface eth0
virtual_router_id 52
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
check_lvs
}
virtual_ipaddress {
192.168.12.102
}
}
virtual_server 192.168.12.101 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
#nat_mask 255.255.255.0
persistence_timeout 50
protocol TCP
real_server 192.168.12.2 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.12.3 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
virtual_server 192.168.12.102 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
#nat_mask 255.255.255.0
persistence_timeout 50
protocol TCP
real_server 192.168.12.2 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.12.3 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
- lvs_master2中的keepalived配置如下:
! Configuration File for keepalived
global_defs {
router_id LVS_BACKUP
}
vrrp_script check_lvs {
script "/etc/keepalived/lvs_check.sh"
interval 2
weight -20
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
check_lvs
}
virtual_ipaddress {
192.168.12.101
}
}
vrrp_instance VI_2 {
state MASTER
interface eth0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
check_lvs
}
virtual_ipaddress {
192.168.12.102
}
}
virtual_server 192.168.12.101 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
#nat_mask 255.255.255.0
persistence_timeout 50
protocol TCP
real_server 192.168.12.2 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.12.3 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
virtual_server 192.168.12.102 80 {
delay_loop 6
lb_algo wrr
lb_kind DR
#nat_mask 255.255.255.0
persistence_timeout 50
protocol TCP
real_server 192.168.12.2 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.12.3 80 {
weight 3
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
- 编写lvs_check.sh脚本。
a=`ipvsadm -ln`
str="Route"
bb=`echo $aa|grep $str|wc -l`
if [ $bb = 0 ];then
sleep 3
aa=`ipvsadm -ln`
bb=`echo $aa|grep $str|wc -l`
if [ $bb = 0 ];then
killall keepalived
fi
fi
启动192.168.12.2和192.16812.3的nginx、double_master_lvsdr0、double_master_lvsdr1服务。启动192.168.12.6和192.168.12.7的tomcat。
-
我们查看lvs_master1的eth0节点信息，发现绑定了vip1(192.168.12.101)
image.png -
查看lvs_master2的eth0节点信息，发现绑定了vip2(192.168.12.102)
image.png -
查看lvs_master1的lvs以及realserver的信息。
image.png -
查看lvs_master2的lvs以及realserver的信息
image.png -
修改hosts文件(C:\Windows\System32\drivers\etc\hosts)，指定cmaxiaoma.mayday.com对应的2个vip。(在hosts里这样设置，达不到负载均衡，只会优先访问192.168.12.101)
image.png -
访问cmazxiaoma.mayday.com
image.png -
我们停止掉lvs_master1.
image.png -
当我们又恢复lvs_master1.vip1又回到了lvs_master1手里，而lvs_master2又失去了vip1。
image.png
image.png
-
在lvs_master2的eth0以及lvs、RealServer信息。
image.png
image.png
Summary
今天加班就到这里了，回去要照顾女朋友了！
