LVS + Keepalived 双主配置
一般场景中实现LVS高可用及后端的LB，同时只有一台LVS提供服务，另一台作为Backup，显然没有做到最大利用。我们可以让两台LVS都作为Master，并又互为Backup，与master-backup架构相比，master-master架构需要多加一个vip。
服务器IP规划
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| lvs1+keepalived：192.168.1.2
lvs2+keepalived：192.168.1.3
web1：192.168.1.4
web2：192.168.1.5
vip：192.168.1.6，192.168.1.7
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Director（LVS+Keepalvied）主机配置
Master Host1 配置
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| [root@localhost ~]# cat /etc/keepalived/keepalived.conf
vrrp_instance bl_one {
state MASTER #指定Keepalived的角色，MASTER为主服务器，BACKUP为备用服务器
interface eth0 #指定HA监测的接口
lvs_sync_daemon_interface eth0
virtual_router_id 38 #虚拟路由标识(1-255)，在一个VRRP实例中主备服务器ID必须一样
priority 150 #优先级，数字越大越优先，主服务器优先级必须高于备服务器
advert_int 3 #设置主备之间同步检查时间间隔，单位秒
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress { #定义虚拟IP地址
192.168.1.6
}
}
vrrp_instance bl_two {
state BACKUP
interface eth0
lvs_sync_daemon_interface eth0
virtual_router_id 48
priority 120
advert_int 3
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.7
}
}
virtual_server 192.168.1.6 80 {
delay_loop 3 #设置健康状态检查时间
lb_algo rr #设置负载调度算法
lb_kind DR #设置LVS实现负载均衡的机制
persistence_timeout 50 #会话保持时间
protocol TCP
real_server 192.168.1.4 80 {
weight 1
TCP_CHECK {
connect_timeout 10 #设置响应超时时间
nb_get_retry 3 #设置超时重试次数
delay_before_retry 3 #设置超时重试间隔
connect_port 80
}
}
real_server 192.168.1.5 80 {
weight 1
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
virtual_server 192.168.1.7 80 {
delay_loop 3
lb_algo rr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.1.4 80 {
weight 1
HTTP_GET {
url {
path /index.html
status_code 200
}
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.1.5 80 {
weight 1
HTTP_GET {
url {
path /index.html
status_code 200
}
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
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Master Host2 配置
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| [root@localhost ~]# cat /etc/keepalived/keepalived.conf
vrrp_instance bl_one {
state BACKUP
interface eth0
lvs_sync_daemon_interface eth0
virtual_router_id 38
priority 120
advert_int 3
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.6
}
}
vrrp_instance bl_two {
state MASTER
interface eth0
lvs_sync_daemon_interface eth0
virtual_router_id 48
priority 150
advert_int 3
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.7
}
}
virtual_server 192.168.1.6 80 {
delay_loop 3
lb_algo rr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.1.4 80 {
weight 1
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.1.5 80 {
weight 1
TCP_CHECK {
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
virtual_server 192.168.1.7 80 {
delay_loop 3
lb_algo rr
lb_kind DR
persistence_timeout 50
protocol TCP
real_server 192.168.1.4 80 {
weight 1
HTTP_GET {
url {
path /index.html
status_code 200
}
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.1.5 80 {
weight 1
HTTP_GET {
url {
path /index.html
status_code 200
}
connect_timeout 10
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
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以上创建了两个实例lb_one、lb_two ，其中A主机做为VIP1地址的master，B主机做为VIP2地址的master，A、B主机互为backup 。另外还有一个技巧点，在master-backup架构中也可以配置多个VIP地址，只需要在实例的VIP配置中增加地址、并在后面指定对应的虚地址后面的realserver即可。在主备脚架中配置多个VIP的方法如下：
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| virtual_ipaddress {
192.168.122.100
192.168.122.110
......
}
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RealServer主机配置
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| [root@localhost # cat dr_client.sh
VIP1=192.168.1.6
VIP2=192.168.1.7
BROADCAST=192.168.1.255
. /etc/rc.d/init.d/functions
case "$1" in
start)
echo "reparing for Real Server"
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
ifconfig lo:0 $VIP1 netmask 255.255.255.255 broadcast $BROADCAST up
ifconfig lo:1 $VIP2 netmask 255.255.255.255 broadcast $BROADCAST up
/sbin/route add -host $VIP1 dev lo:0
/sbin/route add -host $VIP2 dev lo:1
;;
stop)
ifconfig lo:0 down
ifconfig lo:1 down
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 "Usage: lvs {start|stop}"
exit 1
esac
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