keepalived+nginx构建高可用web
一、试验拓扑http://blog.运维网.com/attachment/201201/115342347.png
二、环境描述
WEB1（MASTER）：192.168.232.131
WEB2（BACKUP）：192.168.232.132
VIP ： 192.168.232.150
三、安装配置
#yum -y install keepalived
web1配置信息如下：
# cat /etc/keepalived/keepalived.conf
global_defs {
notification_email {
admin@localhost.com
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_run {
script "/root/nginx_check.sh"
interval 1
weight -2
}
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 55
priority 101
advert_int 1
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.232.150
}
track_script {
chk_run
}
}
web2如下：
# cat /etc/keepalived/keepalived.conf
global_defs {
notification_email {
admin@localhost.com
}
notification_email_from Alexandre.Cassen@firewall.loc
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_run {
script "/root/nginx_check.sh"
interval 1
weight -2
}
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 55
priority 100
advert_int 1
nopreempt
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.232.150
}
track_script {
chk_run
}
}
启动keepalived，#service keepalived start
看下master的日志
VRRP_Instance(VI_HA) Dropping received VRRP packet...
Terminating on signal
Stopping Keepalived v1.2.1 (01/04,2012)
Terminating VRRP child process on signal
Starting Keepalived v1.2.1 (01/04,2012)
Registering Kernel netlink reflector
Registering Kernel netlink command channel
Registering gratutious ARP shared channel
Opening file '/etc/keepalived/keepalived.conf'.
Configuration is using
Using LinkWatch kernel netlink reflector...
VRRP sockpool
Starting VRRP child process, pid=4997
VRRP_Instance(VI_HA) Transition to MASTER STATE
VRRP_Instance(VI_HA) Entering MASTER STATE
VRRP_Instance(VI_HA) setting protocol VIPs.
VRRP_Instance(VI_HA) Sending gratuitous ARPs on eth0 for 192.168.232.150
VRRP_Group(VGM) Syncing instances to MASTER state
Registering new address record for 192.168.232.150 on eth0.
VRRP_Instance(VI_HA) Sending gratuitous ARPs on eth0 for 192.168.232.150
Keepalived_vrrp: VRRP_Instance(VI_HA) Sending gratuitous ARPs on eth0 for 192.168.232.150
ip信息：
# ip a
1: lo:mtu 16436 qdisc noqueue
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:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:6e:b2:0f brd ff:ff:ff:ff:ff:ff
inet 192.168.232.130/24 brd 192.168.152.255 scope global eth0
inet 192.168.232.150/24 scope global secondary eth0
inet6 fe80::20c:29ff:fe6e:b20f/64 scope link
valid_lft forever preferred_lft forever
再看backup的日志：
VRRP_Instance(VI_HA) ignoring received advertisment...
Terminating on signal
Stopping Keepalived v1.2.1 (01/05,2012)
Terminating VRRP child process on signal
Starting Keepalived v1.2.1 (01/05,2012)
Registering Kernel netlink reflector
Registering Kernel netlink command channel
Registering gratutious ARP shared channel
Opening file '/etc/keepalived/keepalived.conf'.
Configuration is using
Using LinkWatch kernel netlink reflector...
VRRP_Instance(VI_HA) Entering BACKUP STATE
VRRP sockpool
Starting VRRP child process, pid=10968
ip信息：
# ip a
1: lo:mtu 16436 qdisc noqueue
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:mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:0c:29:c6:24:a8 brd ff:ff:ff:ff:ff:ff
inet 192.168.232.131/24 brd 192.168.152.255 scope global eth0
inet6 fe80::20c:29ff:fec6:24a8/64 scope link
valid_lft forever preferred_lft forever
四、验证
首先访问看下是谁提供服务：
http://s3.运维网.com/wyfs02/M00/47/D4/wKioL1QALibw0rydAABRHjb2lUQ898.jpg
之后我们把master的keepalived服务关掉，看backup日志就可发现已经切换了
http://s3.运维网.com/wyfs02/M02/47/D2/wKiom1QALQ_ydt5FAABLgOzJwnQ755.jpg
但是现在有个问题就是，当web1在启动时会抢占回来，虽然设置了nopreempt不抢占，但是不生效
所以要将web1的state MASTER改成state BACKUP将2节点都设成BACKUP状态，之后就不会再抢占了
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