keepalived-nginx双主热备

环境介绍

两台服务器 ip 对应设置的两个虚拟IP
node1：192.168.150.129 Virtual IP1：192.168.150.132
node2：192.168.150.131 Virtual IP2：192.168.150.133
DNS域名解析至两个虚拟IP： 192.168.150.132、192.168.150.133
环境安装：
nginx-1.12.0.tar.gz
keepalived-2.0.7.tar.gz

部署

nginx安装不做详述

keepalived安装如下：

安装依赖：

yum -y install gcc gcc+ gcc-c++ popt-devel openssl openssl-devel libssl-dev libnl-devel popt-devel kernel kernel-headers kernel-devel yum install -y libnfnetlink-devel
cd /usr/local/script
wget http://www.keepalived.org/software/keepalived-2.0.7.tar.gz
tar zxvf keepalived-2.0.7.tar.gz
cd keepalived-2.0.7
./configure
make && make install
cp /usr/local/script/keepalived-2.0.7/keepalived/etc/init.d/keepalived /etc/init.d/
cp /usr/local/sbin/keepalived /usr/sbin/
cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived
cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/

配置服务:

先关闭SElinux、配置防火墙 （两台负载均衡机都要做）

vim /etc/sysconfig/selinux
#SELINUX=enforcing #注释掉
#SELINUXTYPE=targeted #注释掉
SELINUX=disabled #增加
setenforce 0 #使配置立即生效

查看防火墙状态:
firewall-cmd --state
停止firewall:
systemctl stop firewalld.service
禁止firewall开机启动:
systemctl disable firewalld.service
启动命令：

/etc/init.d/keepalived start
/etc/init.d/keepalived stop

配置node1：192.168.150.129

vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
   notification_email { #指定keepalived在发生事件时(比如切换)发送通知邮件的邮箱
   }
}
vrrp_script chk_http_port { #检测nginx服务是否在运行。有很多方式，比如进程，用脚本检测等等
    script "/usr/local/script/chk_nginx.sh" #脚本监测
    interval 2 #脚本执行间隔，每2s检测一次
    weight -5 #脚本结果导致的优先级变更，检测失败（脚本返回非0）则优先级 -5
    fall 2 #检测连续2次失败才算确定是真失败。会用weight减少优先级（1-255之间
    rise 1 #检测1次成功就算成功。但不修改优先级
}
# 虚拟IP1, 本机作为Master
vrrp_instance VI_1 { #keepalived在同一virtual_router_id中priority（0-255）最大的会成为master，也就是接管VIP，当priority最大的主机发生故障后次priority将会接管
    state MASTER #指定keepalived的角色，MASTER表示此主机是主服务器，BACKUP表示此主机是备用服务器
    interface ens33 #指定HA监测网络的接口。实例绑定的网卡，因为在配置虚拟IP的时候必须是在已有的网卡上添加
    virtual_router_id 51 #虚拟路由标识，这个标识是一个数字，同一个vrrp实例使用唯一的标识。即同一vrrp_instance下，MASTER和BACKUP必须保持一致
    priority 100 #定义优先级，数字越大，优先级越高，在同一个vrrp_instance下，MASTER的优先级必须大于BACKUP的优先级
    advert_int 1 #设定MASTER与BACKUP负载均衡器之间同步检查的时间间隔，单位是秒
    authentication { #设置验证类型和密码。主从一样
        auth_type PASS #设置vrrp验证类型，主要有PASS和AH两种
        auth_pass 1111 #设置vrrp验证密码，在同一个vrrp_instance下，MASTER与BACKUP必须使用相同的密码才能正常通信
    } 
    virtual_ipaddress { #VRRP HA 虚拟地址 
        192.168.150.132 
    }
track_script { #执行监控的服务。注意这个设置不能紧挨着写在vrrp_script配置块的后面，否则nginx监控失效
    chk_http_port #引用VRRP脚本，即在 vrrp_script 部分指定的名字。定期运行它们来改变优先级，并最终引发主备切换。
}
}
# 虚拟IP2, 本机作为Backup
vrrp_instance VI_2 {
    state BACKUP
    interface ens33
    virtual_router_id 52
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.150.133
    }
}

配置node2：192.168.150.131 (配置说明参考node1)

vi /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
   notification_email {
   }
}
vrrp_script chk_http_port { 
    script "/usr/local/script/chk_nginx.sh"
    interval 2 
    weight -5 
    fall 2 
    rise 1 
}
# 虚拟IP1, 本机作为 BACKUP
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 99
    advert_int 1
     track_interface {
        ens33
    }
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.150.132
    }
}
# 虚拟IP2, 本机作为Master
vrrp_instance VI_2 {
    state MASTER
    interface ens33
    virtual_router_id 52
    priority 100
    advert_int 1
    track_interface {
        ens33
    }
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.150.133
    }
track_script {
    chk_http_port 
}
}

监测脚本：

cat /usr/local/script/chk_nginx.sh 
#!/bin/bash
counter=$(ps -C nginx --no-heading|wc -l)
if [ "${counter}" = "0" ]; then
    /usr/sbin/nginx
    sleep 2
    counter=$(ps -C nginx --no-heading|wc -l)
    if [ "${counter}" = "0" ]; then
        /etc/init.d/keepalived stop
    fi
fi
或者：
#!/bin/bash
if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]
        then
        /usr/local/nginx/sbin/nginx
        sleep 2
        if [ "$(ps -ef | grep "nginx: master process"| grep -v grep )" == "" ]
        then
                  killall keepalived
        fi
fi

测试：

两台同时开启keepalived和nginx ,可以看到ip 132已经绑定到node1的机器上了，ip 133已经绑定到node2的机器上
node1:

[root@node1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:7b:13:26 brd ff:ff:ff:ff:ff:ff
    inet 192.168.150.129/24 brd 192.168.150.255 scope global noprefixroute dynamic ens33
       valid_lft 1494sec preferred_lft 1494sec
    inet 192.168.150.132/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::7df4:88b6:c428:e981/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

node2:

[root@node2 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:98:96:7f brd ff:ff:ff:ff:ff:ff
    inet 192.168.150.131/24 brd 192.168.150.255 scope global dynamic ens33
       valid_lft 1438sec preferred_lft 1438sec
    inet 192.168.150.133/32 scope global ens33 
       valid_lft forever preferred_lft forever
    inet6 fe80::8596:922d:c1d5:3d0a/64 scope link 

在node1机器killall nginx查看监测脚本能否起作用，可以看到nginx会不断的重启。

[root@node1 ~]# ps -ef|grep nginx
root 89129 77881 0 18:17 ? 00:00:00 /bin/bash /usr/local/script/chk_nginx.sh
root 89134 1 0 18:17 ? 00:00:00 nginx: master process /usr/sbin/nginx
root 89137 1581 0 18:17 pts/1 00:00:00 grep --color=auto nginx
nginx 89138 89134 0 18:17 ? 00:00:00 nginx: worker process

停止node1的keepalived，关掉node1的机器、关闭网络等，可以看到ip 132已经自动绑定到node2的机器上

[root@node1 ~]# /etc/init.d/keepalived stop
Stopping keepalived (via systemctl): [ OK ]

[root@node2 ~] ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:98:96:7f brd ff:ff:ff:ff:ff:ff
    inet 192.168.150.131/24 brd 192.168.150.255 scope global dynamic ens33
       valid_lft 1708sec preferred_lft 1708sec
    inet 192.168.150.133/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet 192.168.150.132/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::8596:922d:c1d5:3d0a/64 scope link 
       valid_lft forever preferred_lft forever

重启node1的keepalived：132重新绑定至node1上

[root@node1 ~]# /etc/init.d/keepalived start
Starting keepalived (via systemctl): [ OK ]
[root@app_mq_129 keepalived]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 00:0c:29:7b:13:26 brd ff:ff:ff:ff:ff:ff
    inet 192.168.150.129/24 brd 192.168.150.255 scope global noprefixroute dynamic ens33
       valid_lft 1571sec preferred_lft 1571sec
    inet 192.168.150.132/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::7df4:88b6:c428:e981/64 scope link noprefixroute 

部署完成！！！