基于keepalived实现高可用nginx服务

环境及配置前提说明

主机1，ip:192.168.25.140 运行web服务

主机2，ip:192.168.25.141 运行web服务

主机3，ip:192.168.25.138 运行nginx服务和keepalived服务

主机4，ip:192.168.25.139 运行nginx服务和keepalived服务

1两台nginx主机编译安装nginx服务

    # 下载源码包
    ]# yum install -y make
    ]# yum install -y gcc
    ]# yum -y groupinstall "Development Tools" "Server Platfrom Development"
    ]# yum install pcre-devel openssl-devel zlib-devel -y  手动解决最重要的依赖关系包
    ]# useradd -r nginx 增加一个系统用户
    ]# tar -xf nginx-1.10.0.tar.gz
    ]# cd nginx-1.10.0/
    nginx-1.10.0]# ./configure --prefix=/usr/local/nginx --conf-path=/etc/nginx/nginx.conf --error-log-path=/va/log/nginx.log 
    --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock 
    --user=nginx --group=nginx --with-http_ssl_module --with-http_v2_module --with-http_dav_module 
    --with-http_stub_status_module --with-threads --with-file-aio
    ]# make && make install
    ]# vim /etc/profile.d/nginx.sh
        export PATH=/usr/local/nginx/sbin:$PATH
    ]# . /etc/profile.d/nginx.sh
    ]# nginx -t 检测错误
    ]# nginx -h 可查看命令使用帮助
    启动服务,检测端口是否已经启用
    ]# /usr/local/nginx/sbin/nginx 启动服务
    ]# ss -tnlp 查看80端口是否已经启用,注意,如果httpd服务已经启用了话 这里会启动失败

2两台nginx主机安装keepalived服务

]# yum install keepalived -y

2.1为两台keepalived主机编辑邮件通知脚本

]# vim notify.sh
#!/bin/bash
#
contact='root@localhost'

notify() {
        mailsubject="$(hostname) to be $1, vip floating"
        mailbody="$(date +'%F %T'): vrrp transition, $(hostname) changed to be $1"
        echo "$mailbody" | mail -s "$mailsubject" $contact
}

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

2.2将脚本移动至/etc/keepalived/目录下，并且给脚本执行权限

]# mv notify.sh /etc/keepalived/
]# chmod +x notify.sh

3配置nginx的反代配置文件

    ]# vim /etc/nginx/nginx.conf 编辑主配置文件，在http上下文编辑upstream server,如下；

4配置两台keepalived节点主机配置文件

]# vim  keepalived.conf，详细配置如下；

4.1节点一配置

! Configuration File for keepalived

    global_defs {
       notification_email {
         root@localhost
       }
       notification_email_from keepalived@localhost
       smtp_server 172.0.0.1
       smtp_connect_timeout 30
       router_id node1
       vrrp_mcast_group4 224.0.100.19

    }

    vrrp_script chk_down {
            script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
            interval 1
            weight -5
    }
    vrrp_script chk_nginx {
            script "killall -0 nginx && exit 0 || exit 1"
            interval 1
            weight -5
    }

    vrrp_script chk_nginx
    vrrp_instance VI_1 {
        state MASTER
        interface eth0
        virtual_router_id 1
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass cb77b8da
        }

    virtual_ipaddress {
            192.168.25.142/32 dev eth0 #nginx外网地址
        }
    track_script {
            chk_down
            chk_nginx
        }
        notify_master "/etc/keepalived/notify.sh master"
        notify_backup "/etc/keepalived/notify.sh backup"
        notify_fault "/etc/keepalived/notify.sh fault"
    }

4.2节点二配置

! Configuration File for keepalived

    global_defs {
       notification_email {
         root@localhost
       }
       notification_email_from keepalived@localhost
       smtp_server 172.0.0.1
       smtp_connect_timeout 30
       router_id node1
       vrrp_mcast_group4 224.0.100.19

    }

    vrrp_script chk_down {
            script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
            interval 1
            weight -5
    }
    vrrp_script chk_nginx {
            script "killall -0 nginx && exit 0 || exit 1"
            interval 1
            weight -5
    }

    vrrp_instance VI_1 {
        state BACKUP
        interface eth0
        virtual_router_id 1
        priority 98
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass cb77b8da
        }
        virtual_ipaddress {
            192.168.25.142/32 dev eth0 #nginx外网地址
        }


    track_script {
            chk_down
            chk_nginx
        }
        notify_master "/etc/keepalived/notify.sh master"
        notify_backup "/etc/keepalived/notify.sh backup"
        notify_fault "/etc/keepalived/notify.sh fault"
    }

5为两台RS web服务器编辑主页以便进行测试

]# vim /var/www/html/index.html
    <h1>RS 1</h1> #RS1的主页
    <h1>RS 2</h1> #RS2的主页

6进行访问测试