LB集群之LVS/keepalived
在上一个实验的基础上LVS/DR
(NTA,DR HA 都是用 nginx 服务操作的，省去了安装nginx安装配置)
lvs虽然已经配置成功也实现了负载均衡，但是我们测试的时候发现，当某台real server把httpd进程停掉，那么director照样会把请求转发过去，这样就造成了某些请求不正常。所以需要有一种机制用来检测real server的状态，这就是keepalived。它的作用除了可以检测rs状态外，还可以检测备用director的状态，也就是说keepalived（集HA+LB于一体）可以实现ha集群的功能，当然了也需要一台备用director.
实验环境：三台虚拟机，10.72.4.48 （dir/master）,10.72.4.39(rs2&slave),10.72.4.37 (rs2)
# ipvsadm -C#清空之前的规则
# yum install -y keepalived#安装keepalived
# vim /etc/keepalived/keepalived.conf
state MASTER #备用服务器上为 BACKUP
interface eth0
virtual_router_id 51
priority 100#备用服务器上为90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.72.4.100
}
}
virtual_server 10.72.4.100 80 {
delay_loop 6 #(每隔10秒查询realserver状态)
lb_algo wlc #(lvs 算法)
lb_kind DR #(Direct Route)
persistence_timeout 60 #(同一IP的连接60秒内被分配到同一台realserver)
protocol TCP #(用TCP协议检查realserver状态)
real_server 10.72.4.37 80 {
weight 100 #(权重)
TCP_CHECK {
connect_timeout 10 #(10秒无响应超时)
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 10.72.4.39 80 {
weight 100
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
------------------------------------------------
# scp /etc/keepalived/keepalived.conf 10.72.4.39:/etc/keepalived/keepalived.conf#拷贝到从上
# vim /etc/keepalived/keepalived.conf #只改以下两处，其他地方不都不用改
vrrp_instance VI_1 {
state BACKUP #备用服务器上为 BACKUP
interface eth0
virtual_router_id 51
priority 90#备用服务器上为90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
10.72.4.100
}
}
------------------------------------------
dir ~]# /etc/init.d/keepalived start
Starting keepalived: [ OK]
rs2 ~]# /etc/init.d/keepalived start
Starting keepalived: [OK]
rs1 ~]vim /usr/local/sbin/lvs_nat.sh#编译脚本
#! /bin/bash
vip=http://blog.运维网.com/e/u261/themes/default/images/spacer.gif10.72.4.100
ifconfig lo:0 $vip broadcast $vip netmask http://blog.运维网.com/e/u261/themes/default/images/spacer.gif255.255.255.255 up
route add -host $vip 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
sh /usr/local/sbin/lvs_nat.sh #执行脚本
rs2 ~]vim /usr/local/sbin/lvs_nat.sh#编译脚本
#! /bin/bash
vip=http://blog.运维网.com/e/u261/themes/default/images/spacer.gif10.72.4.100
ifconfig lo:0 $vip broadcast $vip netmask http://blog.运维网.com/e/u261/themes/default/images/spacer.gif255.255.255.255 up
route add -host $vip 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
rs2 ~]sh /usr/local/sbin/lvs_nat.sh #执行脚本
# vim /usr/local/sbin/lvs_dr.sh#编译打开dir 上的端口转发脚本
#! /bin/bash
echo 1 > /proc/sys/net/ipv4/ip_forward
# sh /usr/local/sbin/lvs_dr.sh #执行脚本
http://s2.运维网.com/wyfs02/M02/8B/E3/wKiom1hbjuzwpibmAAHW6vTCe6Y599.jpg
rs2 ~]# /etc/init.d/nginx stop#停掉 rs2 上的nginx ，
Stopping nginx:
#停掉rs2 上的nginx 后，IE 刷新 10.72.4.100，不会再出现rs2 上的内容。且主服务器也会把rs2 的IP 踢除，重新启动rs2 上的nginx 服务，会恢复正常。
http://s3.运维网.com/wyfs02/M02/8B/E4/wKiom1hbktPwiO3SAABwghf6mTQ492.jpg
http://s2.运维网.com/wyfs02/M00/8B/E0/wKioL1hbk3uwwq3nAACJR-5QdzU311.jpg
--------------------------------------------------------
# /etc/init.d/keepalived stop #停掉主dir上的 keepalived ,rs2从上的keepalived就会启动,取代dir 成为主，继续工作。
Stopping keepalived:
http://s5.运维网.com/wyfs02/M00/8B/E0/wKioL1hblt7in9yxAALR7LWQvWo458.jpg
再次重新启动主的 keepalived ，就会恢复到之前的状态。
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