Keepalived双主ipvs集群实现后端nginx负载均衡
实验准备
初始设置
（1）时间同步
systemctl restart chronyd
（2）关闭SELinux和防火墙
（3）互相之间/etc/hosts文件添加对方主机名
（4）确认接口支持多播（组播），略，基本新的网卡都支持。
实验规划
主机：A B C D
A B Keepalived+LVS集群
C D 后端RS
实验步骤
RS主机配置
C D
1每个RS安装nginx服务并配置测试主页
yum -y install nginx
vim /usr/share/nginx/html/index/html
<h1>RS1</h1>
2 每个RS配置两个回环地址
vim setrs.sh
#!/bin/bash
vip1=172.16.42.199
vip2=172.16.42.200
mask=255.255.255.255
iface1="lo:0"
iface2="lo:1"
case $1 in
start)
echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
ifconfig $iface1 $vip1 netmask $mask broadcast $vip1 up
ifconfig $iface2 $vip2 netmask $mask broadcast $vip2 up
route add -host $vip1 dev $iface1
route add -host $vip2 dev $iface2
;;
stop)
ifconfig $iface1 down
ifconfig $iface2 down
echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
;;
*)
echo "Usage: $(basename $0) start|stop"
exit 1
;;
esac
bash -x setrs.sh start
ip a可看到每个RS主机上都配备了两个回环地址
Keepalived+lvs集群配置
A B
yum -y install ipvsadm
yum -y install keepalived
vim /etc/keepalived/keepalived.conf
global_defs {
notification_email {
root@localhost
}
notification_email_from ka1@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 60
vrrp_mcast_group4 224.111.111.222 ##组播地址
}
####虚拟路由相关配置
vrrp_instance VI_1 { ##虚拟路由1
state BACKUP ##此处B为MASTER
interface eth1
virtual_router_id 191 ##上下两个虚拟路由辨识号不能一样，但需主备一样
priority 95
advert_int 1
authentication {
auth_type PASS
auth_pass 0702f7ab ##上下两个虚拟路由验证不能一样，但需主备一样
}
virtual_ipaddress {
172.16.42.199 ##上下两个虚拟路由虚拟路由ip不能一样，但需主备一样
}
}
vrrp_instance VI_2 { ##虚拟路由2
state MASTER ##此处B为BACKUP
interface eth1
virtual_router_id 192
priority 100 ##此处B为95
advert_int 1
authentication {
auth_type PASS
auth_pass 85c9a27b
}
virtual_ipaddress {
172.16.42.200
}
}
####以下是ipvs规则的相关配置
virtual_server 172.16.42.199 80 { ##虚拟路由1对应ipvs规则配置
delay_loop 3
lb_algo sh ##算法为源地址哈希
lb_kind DR ##为dr模型
protocol TCP
real_server 172.16.100.216 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 1
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.250.170 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 1
nb_get_retry 3
delay_before_retry 1
}
}
}
virtual_server 172.16.42.200 80 { ##虚拟路由2对应ipvs规则配置
delay_loop 3
lb_algo sh
lb_kind DR
protocol TCP
real_server 172.16.100.216 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 1
nb_get_retry 3
delay_before_retry 1
}
}
real_server 172.16.250.170 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
connect_timeout 1
nb_get_retry 3
delay_before_retry 1
}
}
}
systemctl stop keepalived
systemctl start keepalived
此时在A B两台主机上都可查看到ipvs规则
[root@centos nginx]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 172.16.42.199:80 sh
-> 172.16.100.216:80 Route 1 0 0
-> 172.16.250.170:80 Route 1 0 0
TCP 172.16.42.200:80 sh
-> 172.16.100.216:80 Route 1 0 0
-> 172.16.250.170:80 Route 1 0 0
ip a 可看到虚拟ip分别漂移在A B 主机端口上
for i in {1..10}; do curl http://172.16.42.200;done
for i in {1..10}; do curl http://172.16.42.199;done
返回的结果始终是第一次匹配到的RS主机页
当停掉A B其中一台主机上的Keepalived服务时，调度并不受影响且故障切换后，同一个客户端访问依然能关联至此前绑定的RS