nginx+keepalived实现双机热备

前言：

通过nginx+keepalived实现双机热备：

 

正文：

nginx、keepalived安装过程略。

服务器：

192.168.236.6：master（主机）

192.168.236.7：backup（备机）

 

开放端口：

停止firewall：systemctl stop firewalld.service

禁止firewalld：systemctl disable firewalld.service

查询防火墙状态：firewall-cmd --state

关闭防火墙：firewall-cmd --state

查询端口是否可用：firewall-cmd --query-port=80/tcp

查询已开放端口：firewall-cmd --list-port

开放端口：firewall-cmd --zone=public --add-port=112/tcp --permanent

keepalived需要开放的端口：112

 

keepalived：

版本：2.0.17

安装目录：/usr/local/src/keepalived-2.0.17/

配置文件：/etc/init.d/keepalived

#!/bin/sh

#

# Startup script for the Keepalived daemon

#

# processname: keepalived

# pidfile: /var/run/keepalived.pid

# config: /usr/local/keepalived/etc/keepalived/keepalived.conf

# chkconfig: - 21 79

# description: Start and stop Keepalived



# Source function library

. /etc/rc.d/init.d/functions



# Source configuration file (we set KEEPALIVED_OPTIONS there)

. /usr/local/keepalived/etc/sysconfig/keepalived



keepalived=/usr/local/keepalived/sbin/keepalived

keepalived_config=/usr/local/keepalived/etc/keepalived/keepalived.conf

keepalived_pid=/usr/local/keepalived/run/keepalived.pid



RETVAL=0



prog="keepalived"



start() {

echo -n $"Starting $prog: "

daemon $keepalived -f ${keepalived_config} ${KEEPALIVED_OPTIONS}

RETVAL=$?

echo

[ $RETVAL -eq 0 ] && touch /var/lock/subsys/$prog

}



stop() {

echo -n $"Stopping $prog: "

killproc $keepalived

RETVAL=$?

echo

[ $RETVAL -eq 0 ] && rm -f /var/lock/subsys/$prog

}



reload() {

echo -n $"Reloading $prog: "

killproc $keepalived -1

RETVAL=$?

echo

}



# See how we were called.

case "$1" in

start)

start

;;

stop)

stop

;;

reload)

reload

;;

restart)

stop

start

;;

condrestart)

if [ -f /var/lock/subsys/$prog ]; then

stop

start

fi

;;

status)

status keepalived

RETVAL=$?

;;

*)

echo "Usage: $0 {start|stop|reload|restart|condrestart|status}"

RETVAL=1

esac



exit $RETVAL

主机配置文件：/usr/local/keepalived/etc/keepalived/keepalived.conf

 

! Configuration File for keepalived

global_defs {
   notification_email {
       419572719@qq.com  # 收件人邮箱地址
   }
   notification_email_from 419572718@qq.com  # 发件人邮箱地址
   smtp_server smtp.qq.com
   smtp_connect_timeout 30
   router_id nginx_master  # 设置nginx master的id，在一个网络应该是唯一的
}

vrrp_script chk_http_port {
    script "/usr/local/src/check_nginx_pid.sh"
    interval 2  # 检测脚本执行的间隔，单位是秒
    weight 2
}

vrrp_instance VI_1 {
    state MASTER  # 指定keepalived的角色，主机配置为MASTER
    interface ens33  # 网卡
    virtual_router_id 51  # 路由编号，同一个集群必须使用同一个路由编号
    priority 100  # 优先级，值越大越优先。
    advert_int 1  # 检查间隔，默认为1s(vrrp组播周期秒数)
    authentication {
        auth_type PASS
        auth_pass 1111  # 不同集群的密码最好不同。
    }
    track_script{
        chk_http_port
    }
    virtual_ipaddress {  #  虚拟IP/VIP：可多设，每行一个
        192.168.236.100  #这些IP地址会通过网卡广播到组网中，同一个集群使用相同VIP（看情况）
    }
}

备机配置文件：/usr/local/keepalived/etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {
   notification_email {
       419572719@qq.com
   }
   notification_email_from 419572718@qq.com
   smtp_server smtp.qq.com
   smtp_connect_timeout 30
   router_id nginx_backup
}

vrrp_script chk_http_port {
    script "/usr/local/src/check_nginx_pid.sh"
    interval 2
    weight 2
}

vrrp_instance VI_1 {
    state BACKUP  # 指定keepalived的角色，备机配置为BACKUP
    interface ens33
    virtual_router_id 51
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    track_script{
        chk_http_port
    }
    virtual_ipaddress {
        192.168.236.100
    }
}

 

nginx检测恢复脚本：/usr/local/src/check_nginx_pid.sh

 

#!/bin/bash
#日志名称
log="/var/log/keepalived.log"  #操作日志存放路径 
exec 2>>$log #如果执行过程中有错误信息均输出到日志文件中
A=`ps -C nginx --no-header |wc -l`
if [ $A -eq 0 ];then
    /usr/sbin/nginx                #重启nginx
    if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then    #nginx重启失败
        exit 1
    else
        exit 0
    fi
else
    exit 0
fi

nginx安装备注：

1、修改nginx权限，让sh脚本可以执行nginx。

2、如果有报错：nginx: [emerg] bind() to x.x.x.x:xxxx failed (13: Permision denied)

需要给nginx使用的端口添加到http允许列表：

查看http允许访问的端口：semanage port -l | grep http_port_t

将要启动的端口加入到如上端口列表中：

semanage port -a -t http_port_t -p tcp xxx （这里不仅要添加nginx的端口，还要添加nginx集群中各服务器的服务接口，所有节点都要添加。）

 

keepalived修改日志文件：（默认日志保存在linux系统日志中）

1、修改配置文件：/usr/local/keepalived/etc/sysconfig/keepalived

KEEPALIVED_OPTIONS="-D -d -S 0"

2、在/etc/rsyslog.conf 末尾添加：

local0.* /var/log/keepalived.log

3、重启日志记录服务

systemctl restart rsyslog

4、重启keepalived

service keepalived restart