实验
内容
keepalived+lvs实现后端web服务的负载均衡与高可用
架构图
环境
ip | 系统 | 软件 | 角色 |
---|---|---|---|
192.168.253.128 | CentOS7 | keepalived | keepalived的MASTER节点 |
192.168.253.158 | CentOS7 | keepalived | keepalived的BACKUP节点 |
192.168.253.145 | CentOS7 | nginx | 后端web服务器 |
192.168.253.129 | CentOS6 | nginx | 后端web服务器 |
第一步:192.168.253.145端安装nginx
systemctl stop firewalld
setenforce 0
#wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo如果已经有epel源不需要执行
yum install nginx -y #nginx需要epel源才可以yum安装
第二步:192.168.253.145上创建nginx起始页,启动nginx
echo "192.168.253.145" > /usr/share/nginx/html/index.html
systemctl start nginx
curl 192.168.253.145 测试一下
第三步:192.168.253.129上安装nginx
/etc/init.d/iptables stop
setenforce 0
#wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-6.repo 已经有epel源不需要执行
yum install nginx -y
第四步:192.168.253.129上创建nginx起始页,启动nginx
echo "192.168.253.129" > /usr/share/nginx/html/index.html
/etc/init.d/nginx start nginx
curl 192.168.253.129测试一下
第五步:在192.168.253.129和192.168.253.145创建一个脚本用于修改内核参数,阻止arp通告和响应,以及在本地环回接口创建vip192.168.253.190/32
[root@localhost ~]# cat RS.sh
#!/bin/bash
#
vip=192.168.253.190 ##vip
mask='255.255.255.255' ##掩码
case $1 in
start)
##阻止arp通告与响应
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 lo:0 $vip netmask $mask broadcast $vip up #设置vip
route add -host $vip dev lo:0 #增加主机路由
;;
stop)
ifconfig lo:0 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
在两台机上都执行
sh RS.sh start #启动脚本
第六步:192.168.253.128端安装keepalived并修改/etc/keepalived/keepalived.conf配置文件
systemctl stop firewalld
setenforce 0
yum install keepalived -y
[root@localhost ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id 192.168.253.128
}
vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 15
priority 95
advert_int 1
authentication {
auth_type PASS
auth_pass 1234
}
virtual_ipaddress {
192.168.253.190/32 dev ens33
}
}
virtual_server 192.168.253.190 80 {
delay_loop 1
lb_algo rr
lb_kind DR
persistence_timeout 1
protocol TCP
real_server 192.168.253.145 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
nb_get_retry 3
delay_before_retry 1
connect_timeout 1
}
}
real_server 192.168.253.129 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
nb_get_retry 3
delay_before_retry 1
connect_timeout 1
}
}
}
第七步:192.168.253.158端安装keepalived并修改/etc/keepalived/keepalived.conf配置文件
systemctl stop firewalld
setenforce 0
yum install keepalived -y
[root@localhost ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost
}
notification_email_from keepalived@localhost
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id 192.168.253.158
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 15
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1234
}
virtual_ipaddress {
192.168.253.190/32 dev ens33
}
}
virtual_server 192.168.253.190 80 {
delay_loop 1
lb_algo rr
lb_kind DR
persistence_timeout 1
protocol TCP
real_server 192.168.253.145 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
nb_get_retry 3
delay_before_retry 1
connect_timeout 1
}
}
real_server 192.168.253.129 80 {
weight 1
HTTP_GET {
url {
path /
status_code 200
}
nb_get_retry 3
delay_before_retry 1
connect_timeout 1
}
}
}
第八步:测试
启动2台keepalived
systemctl start keepalived
可以看到ipvs规则已经产生了。以及vip在192.168.253.128上
然后我们curl一下192.168.253.190
我们使用的调度方法是轮询这里一直是192.168.253.128
解决方法:将配置文件/etc/keepalived/keepalived.conf的persistence_timeout 1这一项删掉,这一项是表示持久链接
然后重启2个keepalived
systemctl restart keepalived
lvs测试没问题。这时候试试高可用,我们把192.168.253.128这个主机的keepalived down掉
systemctl stop keepalived
这时候再继续访问192.168.253.190
同时也可以看到192.168.253.190这个vip飘到192.168.253.158这个BACKUP节点上了。ipvsadm的规则也添加完成。