【 Keepalived 】Nginx or Http 主-主模式

上一篇：【 Keepalived 】Nginx or Http 主-备模式

在此基础上进行修改并实现 Keepalived主-主模式

首先，需要理解的是：主-备模式是一个VIP在工作，主-主模式则需要两个VIP来工作。一旦其中一台主机出现问题，则两个VIP都会绑定到同一台主机上，待到故障解除，重新启动httpd服务，恢复正常。

ka1 配置文件：

! Configuration File for keepalived

global_defs {
notification_email {
root@localhost
}
notification_email_from root@localhost
smtp_server localhost
smtp_connect_timeout 30
router_id NodeA
}

vrrp_script check_nginx {
script "/etc/keepalived/bash/check_nginx.sh"
interval 5
weight -10
}

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_nginx
}
virtual_ipaddress {
192.168.2.200/24
}
}
vrrp_instance VI_2 {
state BUCKUP
interface eth0
virtual_router_id 52
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
check_nginx
}
virtual_ipaddress {
192.168.2.201/24
}
}

ka2 配置文件：

! Configuration File for keepalived

global_defs {
notification_email {
root@localhost
}
notification_email_from root@localhost
smtp_server localhost
smtp_connect_timeout 30
router_id NodeB
}

vrrp_script check_nginx {
script "/etc/keepalived/bash/check_nginx.sh"
interval 5
weight -10
}

vrrp_instance VI_1 {
state BACKUP
interface eth1
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
check_nginx
}
virtual_ipaddress {
192.168.2.200/24
}
}
vrrp_instance VI_2 {
state MASTER
interface eth1
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
check_nginx
}
virtual_ipaddress {
192.168.2.201/24
}
}

测试：

正常情况下：

ka1:

[ka1 root@192.168.2.10 ~]#ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:39:92:4f brd ff:ff:ff:ff:ff:ff
inet 192.168.2.10/24 brd 192.168.2.255 scope global eth0
inet 192.168.2.200/24 scope global secondary eth0
inet6 fe80::20c:29ff:fe39:924f/64 scope link
valid_lft forever preferred_lft forever

ka2:

[ka2 root@192.168.2.11 ~]#ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:7b:9f:8c brd ff:ff:ff:ff:ff:ff
inet 192.168.2.11/24 brd 192.168.2.255 scope global eth1
inet 192.168.2.201/24 scope global secondary eth1
inet6 fe80::20c:29ff:fe7b:9f8c/64 scope link
valid_lft forever preferred_lft forever

当ka1 httpd出现错误时：

ka1 VIP被转移

[ka1 root@192.168.2.10 ~]#ip  a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:39:92:4f brd ff:ff:ff:ff:ff:ff
inet 192.168.2.10/24 brd 192.168.2.255 scope global eth0
inet6 fe80::20c:29ff:fe39:924f/64 scope link
valid_lft forever preferred_lft forever

ka2 被绑定了两个VIP
[ka2 root@192.168.2.11 ~]#ip  a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue state UNKNOWN
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:7b:9f:8c brd ff:ff:ff:ff:ff:ff
inet 192.168.2.11/24 brd 192.168.2.255 scope global eth1
inet 192.168.2.201/24 scope global secondary eth1
inet 192.168.2.200/24 scope global secondary eth1
inet6 fe80::20c:29ff:fe7b:9f8c/64 scope link
valid_lft forever preferred_lft forever

再三强调：在keepalived使用中，脚本很重要很重要。要经过严格的测试调试，才能使用，我这里在贴一遍脚本，上个主-备中也有脚本，需要灵活修改的地方我红色标识出来：

#!/bin/bash

pidfile=/var/lock/subsys/`basename $0`.pid
if [ -f $pidfile ] && [ -e /proc/`cat $pidfile` ] ; then
exit 1
fi
trap "rm -rf $pidfile ; exit 0" 1 2 3 15
echo $$ > $pidfile
maxfails=3
fails=0
success=0

while [ 1 ]
do

/usr/bin/wget --timeout=3 --tries=1 http://192.168.2.11/ -q -O /dev/null && ping -c1 192.168.2.1 &> /dev/null
if [ $? -ne 0 ] ; then
let fails=$[$fails+1]
success=0
else
fails=0
let success=$[$success+1]
fi

if [ $fails -ge $maxfails ] ; then
fails=0
success=0
#check keepalived is running ? try to stop it
/etc/init.d/keepalived status | grep 正在运行
if [ $? -eq 0 ] ; then
/usr/bin/logger -is "local service fails $maxfails times ... try to stop keepalived."
/etc/init.d/keepalived stop 2>&1 | /usr/bin/logger
fi

fi

if [ $success -gt $maxfails ] ; then
#check keepalived is stopped ? try to start it
/etc/init.d/keepalived status | grep 已停
if [ $? -eq 0 ] ; then
/usr/bin/logger -is "service changes normal, try to start keepalived ."
/etc/init.d/keepalived start
fi
success=0
fi
sleep 3

done

注意：此脚本必须有访问默认页面支持。