部署nginx+keepalived实现双机双主高可用性环境

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双机热备，意思是说两台机器一台处于运行中，另一台永久处于备份。这样的话资源浪费严重，适用于国企,政府类系统。今天我们所讲的是双机双主热备，意味着两台机器同时处于工作状态，两台主机又同时为备份状态。

准备：

两台主机192.168.100.128/24 192.168.100.129/24

两个单独的ip 192.168.100.133/24 192.168.100.134/24

可以将你域名解析到这两个单独的ip,keepalived会将这两个ip通过虚拟ip技术漂移到两台主机上。如果一台机器down，keepalived会将原本漂移在它身上的ip,漂移到另一台机器上，这样就实现了双机双主互为主机和备份。

安装

此处省略......

配置

 

128机器 keepalived.conf配置文件

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global_defs {
notification_email {
1491318829@qq.com
}
notification_email_from keepalived@localhost.com
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_http_port {
script "/opt/nginx_pid.sh"
interval 2
weight -20 #每检查一次，权重减去20
}
vrrp_instance VI_1 {
state MASTER
interface eth1 #注意看到你本机的网络接口
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port
}
virtual_ipaddress {
192.168.100.133
}
}
vrrp_instance VI_2 {
state BACKUP
interface eth1 #两处都为本机的网络接口
virtual_router_id 52
priority 99 #权重
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.100.134/24
}
}

129机器 keepalived.conf配置文件

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global_defs {
notification_email {
1491318829@qq.com               #接收警报的email地址,可以添加多个
}
notification_email_from admin@caicongyang.com   ###发件人地址
smtp_server 127.0.0.1          ###发送邮件的服务器
smtp_connect_timeout 30      ###超时时间
router_id LVS_DEVEL      ####load balancer 的标识 ID,用于email警报
}
vrrp_script chk_http_port {
script "/opt/nginx_pid.sh" ####检测nginx状态的脚本路径
interval 2
weight -20
}
vrrp_instance VI_1 {
state BACKUP
interface eth2
virtual_router_id 51
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.100.133/24
}
}
vrrp_instance VI_2 {
state MASTER
interface eth2
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port
}
virtual_ipaddress {
192.168.100.134/24
}
}

 

启动和测试

启动nginx

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#/usr/local/nginx/sbin/nginx

启动keepalived

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#service keepalived start


测试

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#ip a


128机器结果

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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:ff:ca:24 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.128/24 brd 192.168.100.255 scope global eth1
    inet 192.168.100.133/32 scope global eth1
    inet6 fe80::20c:29ff:feff:ca24/64 scope link
       valid_lft forever preferred_lft forever
</broadcast,multicast,up,lower_up></loopback,up,lower_up>


129机器结果

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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: eth2: <broadcast,multicast,up,lower_up> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:c0:02:92 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.129/24 brd 192.168.100.255 scope global eth2
    inet 192.168.100.134/24 scope global secondary eth2
    inet6 fe80::20c:29ff:fec0:292/64 scope link
       valid_lft forever preferred_lft forever
</broadcast,multicast,up,lower_up></loopback,up,lower_up>


我们可以看到ip 133已经绑定到128的机器上了，134已经绑定到129的机器上了 接下来我们可以利用在128机器killall nginx查看上篇文章中的脚本能否起作用，结果是我们可以看到nginx会不断的重启。 那我们直接关掉128的机器，或者关闭的它的网络，然后看到ip133是否能自动绑定到129的机器上呢？结果当然是可以的

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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: eth2: <broadcast,multicast,up,lower_up> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:c0:02:92 brd ff:ff:ff:ff:ff:ff
    inet 192.168.100.129/24 brd 192.168.100.255 scope global eth2
    inet 192.168.100.134/24 scope global secondary eth2
    inet 192.168.100.133/24 scope global secondary eth2
    inet6 fe80::20c:29ff:fec0:292/64 scope link
       valid_lft forever preferred_lft forever</broadcast,multicast,up,lower_up></loopback,up,lower_up>

如同上篇文章所说的，你可以用一下命令查看整个过程

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#tail -f /var/log/messages

 

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