keepalived+nginx构建高可用web

pangxia75

　　一、试验拓扑

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：

　　

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

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