keepalive_docker_nginx实践

我的本地环境，一台 Unbuntu 18.04 系统的物理机
想实践下 虚拟 ip，keepalive
就一台机器，所以用 docker 来实践一下。

关于虚拟 ip, 可以看下这篇文章
https://www.gitos.org/2019/08/19/vip-ha.html

关于 docker, keepalive 基本按这篇文章
https://www.jianshu.com/p/6a8f38b8076d

修改 dockerfile，减少重复下载环境

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FROM centos:latest
MAINTAINER relengxing<relengxing@outlook.com>

RUN yum install -y gcc openssl-devel popt-devel
RUN yum install -y net-tools
RUN yum install -y vim
RUN yum install -y keepalived
RUN yum install -y nginx

启动 centos 容器
–privileged=true 获取特权
/sbin/init：这个地方是实测 /bin/bash，会有权限没有。因为我还实验了下手动加虚拟 ip

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docker run --name centos_master -itd --privileged=true relengxing/centos:v1 /sbin/init
docker run --name centos_slave -itd --privileged=true relengxing/centos:v1 /sbin/init

可以进容器查看 ip 地址

Master 节点
ifconfig

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eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 172.17.0.3 netmask 255.255.0.0 broadcast 172.17.255.255
ether 02:42:ac:11:00:03 txqueuelen 0 (Ethernet)

在容器外则通过 docker network
docker network ls
docker network inspect d8c58097a4c3

ifconfig eth0:0 172.17.0.88 netmask 255.255.0.0 up
ifconfig eth0:0 down

修改/etc/keepalived/keepalived.conf的内容

主节点

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! Configuration File for keepalived
global_defs {
   notification_email {
     xuad@xuad.com
   }
   notification_email_from root@xuad.com
   smtp_server mail.xuad.com
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_script chk_nginx {
    script "/etc/keepalived/nginx_pid.sh"   # 检查nginx状态的脚本
    interval 2
    weight 3
}

vrrp_instance VI_1 {
    state MASTER     #备份服务器上将MASTER改为BACKUP
    interface eth0
    virtual_router_id 51
    priority 101       #备份服务上将100改为小于100，可配置成90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.17.0.99    #有多个vip可在下面继续增加
    }
    track_script {
        chk_nginx
    }
}

备份节点

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! Configuration File for keepalived

global_defs {
   notification_email {
     xuad@xuad.com
   }
   notification_email_from root@xuad.com
   smtp_server mail.xuad.com
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_script chk_nginx {
    script "/etc/keepalived/nginx_pid.sh"   # 检查nginx状态的脚本
    interval 2
    weight 3
}

vrrp_instance VI_1 {
    state BACKUP     #备份服务器上将MASTER改为BACKUP
    interface eth0
    virtual_router_id 51
    priority 99       #备份服务上将100改为小于100，可配置成90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.17.0.99    #有多个vip可在下面继续增加
    }
    track_script {
        chk_nginx
    }
}

nginx_pid.sh

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#检测nginx是否存活的脚本
A=`ps -ef | grep nginx | grep -v grep | wc -l`
if [ $A -eq 0 ];then
  nginx
  sleep 2
  if [ `ps -ef | grep nginx | grep -v grep | wc -l` -eq 0 ];then
      #killall keepalived
      ps -ef|grep keepalived|grep -v grep|awk '{print $2}'|xargs kill -9
  fi

fi

修改 nginx 显示的页面，我就修改了这一行，标示是主机还是备份机

主节点

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<strong>nginx  master Node</strong> HTTP server after it has been

从节点

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<strong>nginx  Slave Node</strong> HTTP server after it has been

然后在主机运行
curl 172.17.0.99
显示

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...
   <strong>nginx   master Node</strong> HTTP server after it has been
...

关闭主节点后
然后在主机运行
curl 172.17.0.99
显示

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...
   <strong>nginx   slave Node</strong> HTTP server after it has been
...

遇到一个问题没有解决

在主节点运行
nginx -s stop 推出 nginx 后，没有切换到从节点，必须关闭主节点。

更新：
这个问题看了下
是 nginx 检测脚本的问题
修改为

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#!/bin/bash
# 如果进程中没有nginx则将keepalived进程kill掉
A=`ps -C nginx --no-header |wc -l`      ## 查看是否有 nginx进程 把值赋给变量A
if [ $A -eq 0 ];then                    ## 如果没有进程值得为 零
    systemctl stop keepalived.service           ## 则结束 keepalived 进程
fi

成功了

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