keepalived高可用LVS与Nginx

2017-02-14 20:19

一、Keepalived

keepalived前提准备见上文 -->Keepalived基础配置

二、keepalived高可用LVS

keepalived能够根据配置文件生成ipvs规则,同时可以对后端各RS做健康状态检测

1、实验清单

director1: node1 192.168.0.40

director2: Nginx 192.168.0.108

Vip:192.168.0.80

RS1(httpd):192.168.0.100

RS2(httpd):192.168.0.101

2、配置文件

[root@Nginx ~]# cd /etc/keepalived/
[root@Nginx keepalived]# vim keepalived.conf
! Configuration File for keepalived

global_defs {
   notification_email {
	root@localhost
   }
   notification_email_from kaadmin@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_script chk_mt {
    script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
    interval 1
    weight -2
}
vrrp_instance VI_1 {
    state MASTER               #node1须修改为BACKUP
    interface eth0
    virtual_router_id 51
    priority 100               #node1降低优先级
    advert_int 1 
    authentication {
        auth_type PASS
        auth_pass 71988d704dcae985
    }
    virtual_ipaddress {
        192.168.0.80/32
    }
    track_script {
	chk_mt	
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}

virtual_server 192.168.0.80 80 {
    delay_loop 6     #服务器轮询6次超时           
    lb_algo rr       #LVS调度算法
    lb_kind DR       #LVS转发方法
    nat_mask 255.255.255.0     #掩码
    persistence_timeout 50     #长链接时间
    protocol TCP               #tcp协议
    ha_suspend                 #在无vip情形下,不再进行健康状态检测
    sorry_server 127.0.0.1 80        #当RS全宕机时,sorry_server提供错误页面
    real_server 192.168.0.100 80 {          #RS的ip,端口
        weight 1                            #权重
        HTTP_GET {                          #检测类型,这里是HTTP_GET
            url {                           #检测请求的类型,这里是状态检测
              path /
	      status_code 200
            }
            connect_timeout 3               #连接超时时间
            nb_get_retry 3                  #重试次数
            delay_before_retry 3            #重试前延迟时间
        }
    }
   real_server 192.168.0.101 80 {
        weight 2
        HTTP_GET {
            url {
              path /
              status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

}

3、定义状态转变后发邮件的notify脚本(来自马哥文档)

#!/bin/bash
# 

vip=192.168.0.80
contact='root@localhost'

notify() {
    mailsubject="`hostname` to be $1: $vip floating"
    mailbody="`date '+%F %H:%M:%S'`: vrrp transition, `hostname` changed to be $1"
    echo $mailbody | mail -s "$mailsubject" $contact
}

case "$1" in
    master)
        notify master
        exit 0
    ;;
    backup)
        notify backup
        exit 0
    ;;
    fault)
        notify fault
        exit 0
    ;;
    *)
        echo 'Usage: `basename $0` {master|backup|fault}'
        exit 1
    ;;
esac

二、高可用Nginx

1、在Nginx主机上配置反向代理upstream

http区段配置    
    upstream nodeserver{
       server 192.168.0.30;
       server 192.168.0.40;
    }
server区段配置
    location / {
         proxy_pass http://nodeserver;
         proxy_set_header Host    $host;
         proxy_set_header X-Real-IP  $remote_addr;
         add_header X-Cache $upstream_cache_status;
         }

2、配置keepalived,加入如下配置

global_defs {
   notification_email {
	root@localhost
   }
   notification_email_from kaadmin@localhost
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_script chk_nginx {
    script "killall -0 nginx &> /dev/null"
    interval 1
    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 71988d704dcae985
    }
    virtual_ipaddress {
        192.168.0.80/32
    }
    track_script {
	chk_nginx	
    }
    notify_master "/etc/keepalived/notify.sh master"
    notify_backup "/etc/keepalived/notify.sh backup"
    notify_fault "/etc/keepalived/notify.sh fault"
}