cf2000 发表于 2018-11-12 06:50:30

Keepalived 高可用ipvs和nginx服务

  Keepalived 高可用ipvs和nginx服务
  ============================================================================
  概述:
  本章讲主要介绍keepalived高可用ipvs服务和nginx服务,内容如下:

[*]  keepalived 配置文件中Virtual_server(虚拟服务器)的配置格式及常用参数;
[*]  keepalived高可用ipvs-dr模型实验过程详解;
[*]  keepalived调用外部辅助脚本实现资源监控及调其优先级;
[*]  keepalived高可用nginx服务;
[*]  总结keepalined高可用nginx及ipvs的配置示例以及通知脚本
  ============================================================================
  回顾:

Virtual Server(虚拟服务器):
  1.配置参数:
  ★虚拟服务器的配置格式:
virtual_server IP port |  
virtual_server fwmark int
  
{
  ...
  real_server {
  ...
  }
  ...
  
}
  ★常用参数
  
keepalived高可用的ipvs-dr集群
  前面讲到用LVS的DR模式来实现Web应用的负载均衡。为了防止LVS服务器自身的单点故障导致整个Web应用无法提供服务,因此还得利用Keepalived实现lvs的高可用性。
  
  1.实验原理:

[*]  即客户端访问VIP(域名解析到VIP),LVS接收情况后根据负载均衡调度算法,转发请求到真实服务器,真实服务器接收到客户端请求后,将处理结果直接返回给客户端。
[*]  实验原理图如下:(借用别人的)

  2.实验环境准备

[*]  准备四台虚拟主机,两台作为real_server,两台作为keepalived+lvs-dr模型的调度器;
[*]  在两个RS上修改内核参数,来限制arp响应和通告的级别;
[*]  配置两台keepalived+lvs-dr调度器的virtual_server
  3.ip地址规划:

[*]  keepalived+lvs-dr模型的调度器
  node1:10.1.252.161
  node2:10.1.249.203
[*]  要转移的ip地址:
  10.1.252.73,把其80端口定义为集群服务
[*]  Real_server
  RS 1:10.1.252.37
  RS 2:10.1.252.153
  其80端口分别向外提供web服务
  4.实验环境搭建:
  1)首先为两台RS准备httpd服务,并提供测试页面如下:
  RS 1

  RS 2为一台CentOS 6主机

  2)接下来我们要修改两台RS的内核参数arp_ignore和arp_announce,然后配置其本地lo网卡的网卡别名作为VIP(配置可参考先前的文档脚本),如下:
  RS 1 vip如下:
  
  RS 2 vip如下:

  
  5.配置调度器node1,和node2,的keepalived服务,手动测试看能否调度到后端RS,过程如下:
  1)node1配置如下:
# cat/etc/keepalived/keepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   smtp_connect_timeout 30
  
   router_id node1
  
   vrrp_mcast_group4 224.0.100.19
  
}
  

  
vrrp_instance VI_1 {
  
    state MASTER
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 100
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736
  
    }
  
    notify_master "/etc/keepalived/notify.sh master"
  
    notify_backup "/etc/keepalived/notify.sh backup"
  
    notify_fault "/etc/keepalived/notify.sh fault"
  
}
  2)node2,配置如下;
# cat /etc/keepalived/keepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   smtp_connect_timeout 30
  
   router_id node1
  
   vrrp_mcast_group4 224.0.100.19
  
}
  

  
vrrp_instance VI_1 {
  
    state BACKUP
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 98
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736
  
    }
  
   notify_master "/etc/keepalived/notify.sh master"
  
   notify_backup "/etc/keepalived/notify.sh backup"
  
   notify_fault "/etc/keepalived/notify.sh fault"
  
}
  3)在node1上对转移ip:10.1.252.73的80端口定义集群服务,如下:

  4)启动node1节点上的keepalived服务,然后在node2上做测试,如下:
  启动node1,之后查看ip,因为此时node1为主节点,所以转移ip在node1上,如下:

  在node2上做测试,可以看到是以轮询的方式响应,如下:

  5)关闭node1上的keepalived服务,使10.1.252.73的地址转移到node2,以同样的方法在node2上定义转移ip的集群服务,在node1上测试发现,同样可以以轮询的方式正常调度到后端的RS服务器。

  
  6.如上,两个节点手动测试都没有问题,清空两个调度器上的定义的集群服务;接下来我们要通过定义keepalived的配置文件来自动生成ipvsadm定义的规则。
  1)首先编辑node1的配置文件,定义virtual server(虚拟主机服务),如下:
# cat keepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   smtp_connect_timeout 30
  
   router_id node1
  
   vrrp_mcast_group4 224.0.100.19
  
}
  

  
vrrp_instance VI_1 {
  
    state MASTER
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 100
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736
  
    }
  
    notify_master "/etc/keepalived/notify.sh master"
  
    notify_backup "/etc/keepalived/notify.sh backup"
  
    notify_fault "/etc/keepalived/notify.sh fault"
  
}
  

  
virtual_server 10.1.252.73 80 {       # 定义转移ip端口80的集群服务
  
    delay_loop 3
  
    lb_algo rr
  
    lb_kind DR
  
    protocol TCP
  

  
    real_server 10.1.252.37 80 {      # 定义集群服务包含的RS 1
  
         weight 1                     # 权重为1
  HTTP_GET {                   # 定义RS1的健康状态检测
  url {
  path /
  status_code 200
  }
  connect_timeout 1
  nb_get_retry 3
  delay_before_retry 1
  }
  
    }
  
    real_server 10.1.252.153 80 {      # 定义集群服务包含的RS 2
  
         weight 1                      # 权重为1
  HTTP_GET {                  # 定义RS2的健康状态检测
  url {
  path /
  status_code 200
  }
  connect_timeout 1
  nb_get_retry 3
  delay_before_retry 1
  }
  
    }
  
}
  同理,在node2的节点上也添加定义virtual server,如下:
# catkeepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   smtp_connect_timeout 30
  
   router_id node1
  
   vrrp_mcast_group4 224.0.100.19
  
}
  

  
vrrp_instance VI_1 {
  
    state BACKUP
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 98
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736
  
    }
  
    notify_master "/etc/keepalived/notify.sh master"
  
    notify_backup "/etc/keepalived/notify.sh backup"
  
    notify_fault "/etc/keepalived/notify.sh fault"
  
}
  

  
virtual_server 10.1.252.73 80 {
  
    delay_loop 3
  
    lb_algo rr
  
    lb_kind DR
  
    protocol TCP
  

  
    real_server 10.1.252.37 80 {
  
         weight 1
  HTTP_GET {
  url {
  path /
  status_code 200
  }
  connect_timeout 1
  nb_get_retry 3
  delay_before_retry 1
  }
  
    }
  
    real_server 10.1.252.153 80 {
  
         weight 1
  HTTP_GET {
  url {
  path /
  status_code 200
  }
  connect_timeout 1
  nb_get_retry 3
  delay_before_retry 1
  }
  
    }
  
}
  7.如上,两个节点node1和node2都已经定义好虚拟主机的集群服务,现在我们开始测试。
  1)启动node1和node2上的keepalived服务,因为node1为主节点,所以首先连接转移ip的集群服务,如下:

  使用curl测试访问发现,以轮询的方式响应,如下:

   现在我停止后端主机RS1,再次在node1上使用ipvsadm查看,RS1已经不存在了,使用curl请求,这是只有RS2响应,如下:
# ipvsadm -Ln  
IP Virtual Server version 1.2.1 (size=4096)
  
Prot LocalAddress:Port Scheduler Flags
  
-> RemoteAddress:Port         Forward Weight ActiveConn InActConn
  
TCP10.1.252.73:80 rr
  
-> 10.1.252.153:80            Route   1      0          0
  
You have new mail in /var/spool/mail/root
# for i in {0..9};do curl http://10.1.252.73 ;done  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  
RS 2 CentOS 6.8
  把RS1启动,3s之后ipvsadm规则就又检测到了,使用curl请求,后端主机又是以轮询的方式响应:
# ipvsadm -Ln  
IP Virtual Server version 1.2.1 (size=4096)
  
Prot LocalAddress:Port Scheduler Flags
  
-> RemoteAddress:Port         Forward Weight ActiveConn InActConn
  
TCP10.1.252.73:80 rr
  
-> 10.1.252.37:80               Route   1      0          0
  
-> 10.1.252.153:80            Route   1      0          0
# for i in {0..9};do curl http://10.1.252.73 ;done  
RS 1
  
RS 2 CentOS 6.8
  
RS 1
  
RS 2 CentOS 6.8
  
RS 1
  
RS 2 CentOS 6.8
  
RS 1
  
RS 2 CentOS 6.8
  
RS 1
  
RS 2 CentOS 6.8
  如果我们把后端的两台RS都停止服务,发现再使用ipvsadm就检测不到了,使用curl访问,提示拒绝访问,如下:
# for i in {0..9};do curl http://10.1.252.73 ;done  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  
curl: (7) Failed connect to 10.1.252.73:80; Connection refused
  8.现在我们就需要定义一个sorry_server,可以用来提醒用户,集群服务出现故障。这里要使用调度器本身的httpd服务来做更合适;并且,要保证两台调度器的web服务都启动起来。
  注意:调度器的web服务在这是没有用的,因为80端口直接在INPUT链上已经被劫走,当做集群服务了,所以调度器上的web服务只能当做sorry_server。
  1)在node1和node2上定义sorry_server如下:(以node1为例)
# catkeepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   smtp_connect_timeout 30
  
   router_id node1
  
   vrrp_mcast_group4 224.0.100.19
  
}
  

  
vrrp_instance VI_1 {
  
    state MASTER
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 100
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736
  
    }
  
    notify_master "/etc/keepalived/notify.sh master"
  
    notify_backup "/etc/keepalived/notify.sh backup"
  
    notify_fault "/etc/keepalived/notify.sh fault"
  
}
  

  
virtual_server 10.1.252.73 80 {
  
    delay_loop 3
  
    lb_algo rr
  
    lb_kind DR
  
    protocol TCP
  

  
    sorry_server 127.0.0.1 80   # 定义的 sorry_server为本机的80端口
  

  
    real_server 10.1.252.37 80 {
  
         weight 1
  HTTP_GET {
  url {
  path /
  status_code 200
  }
  connect_timeout 1
  nb_get_retry 3
  delay_before_retry 1
  }
  
    }
  
    real_server 10.1.252.153 80 {
  
         weight 1
  HTTP_GET {
  url {
  path /
  status_code 200
  }
  connect_timeout 1
  nb_get_retry 3
  delay_before_retry 1
  }
  
    }
  
}
  2)然后我们编辑本机httpd服务的映射根目录,添加提醒用户的测试页面,如下:
# echo "LB Cluster Fault,this is Sorry Server 1" > /var/www/html/index.html  
# cat /var/www/html/index.html
  
LB Cluster Fault,this is Sorry Server 1
  3)在后端两台RS停止服务的情况下,使用ipvsadm查看,可以看到有本机的定义的sorry_server,使用curl访问如下:
# ipvsadm -Ln  
IP Virtual Server version 1.2.1 (size=4096)
  
Prot LocalAddress:Port Scheduler Flags
  
-> RemoteAddress:Port         Forward Weight ActiveConn InActConn
  
TCP10.1.252.73:80 rr
  
-> 127.0.0.1:80               Route   1      0          0
# for i in {0..9};do curl http://10.1.252.73 ;done  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  
LB Cluster Fault,this is Sorry Server 1
  4)后端主机只要有一个RS启动,3s之后sorry_server就会下线了,由后端主机提供服务。
  如上,整个过程就是利用keepalived高可用lvs-dr负载均衡的web集群。。。
  =============================================================================
keepalived实现优先级动态调整;
  keepalived调用外部的辅助脚本进行资源监控,并根据监控的结果状态能实现优先动态调整;

  演示:
   我们在前面的试验中,每次如果由主动节点跳转到被动节点,都是手动把keepalived服务停掉才能实现。但是在实际生产环境中,如果我们不想让他停止服务,只是暂时的进行维护,那该怎么办呢?
  keeoalived有一个功能,可以调用外部脚本来完成资源监控,然后根据资源监控的结果,来完成优先级的动态调整。
  1)这里我定义一个外部脚本,如果在/etc/keepalived/下存在down文件,则节点优先级减5,编辑配置文件,如下:
# cat keepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   smtp_connect_timeout 30
  
   router_id node1
  
   vrrp_mcast_group4 224.0.100.19
  
}
  
# 定义外部脚本,如果/etc/keepalived/down存在,则返回值为1,否则为0
  
vrrp_script chk_down {
  
      script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"
  
      interval 1   # 每个1s钟检测一次
  
      weight -5    # 优先级减去5
  
}
  

  
vrrp_instance VI_1 {
  
    state MASTER
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 100
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736
  
    }
  
    track_script {   # 调用定义的外部脚本
  
      chk_down
  
    }
  

  
    notify_master "/etc/keepalived/notify.sh master"
  
    notify_backup "/etc/keepalived/notify.sh backup"
  
    notify_fault "/etc/keepalived/notify.sh fault"
  
}
  2)同样的定义在节点node2也编辑过去,然后保存,现在我们来测试,启动node1和node2的keepalived服务,此时node1因为优先级高,所以资源ip在主节点node1,如下:

  3)然后我们在主节点node1的/etc/keepalived下创建一个down文件,可以发现node1的资源ip已经转移到备用节点node2上了,如下:

  备用节点查看如下:

  现在,我们把主节点node1上的down文件删除,发现1秒钟之后,资源ip又被node1抢了会来,如下:

keepalived高可用nginx服务
  
  1.实验拓扑图
  2.实验环境准备

[*]  准备四台虚拟主机,两台作为real_server,两台配置nginx服务作为调度器;
[*]  在两台nginx调度器上配置upstream模块,然后proxy反代到两台后端主机
[*]  配置两台nginx调度器的virtual_serve
  3.ip地址规划和高可用lpvs-dr相同
  4.实验环境搭建如下:
  1)首先,在作为两台nginx调度器上配置配置upstream模块,然后proxy反代到两台后端主机,如下:
  在/etc/nginx/nginx.conf中的http配置段定义后端web服务器组;
  
  在/etc/nginx/conf.d/default.conf的server中定义proxy反向代理
  
  node2上的nginx配置和node1是相同的,这里不在列出。
  2)配置node1和node2上的keepalived服务,使用nginx不需要定义virtual_server,如下:
# cat keepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   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_instance VI_1 {
  
    state MASTER
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 100
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736
  
    }
  
    track_script {
  
      chk_down
  
    }
  

  
    notify_master "/etc/keepalived/notify.sh master"
  
    notify_backup "/etc/keepalived/notify.sh backup"
  
    notify_fault "/etc/keepalived/notify.sh fault"
  
}
  5.如上,整个环境及配置就已经完成了,现在,启动主备节点node1上的nginx服务,和keepalived服务,查看主节点node1的ip,发现资源ip在node1上,如下:

  1)测试,在客户端请求nginx调度器上的资源ip,可以发现后端web服务器以轮询的方式响应客户端请求,如下:
# for i in {0..9};do curl http://10.1.252.73;done  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  2)在主节点node1的/etc/keepalived/下创建一个down文件,因为前面定义了一个调用外部脚本,改变其优先级,所以,这时node1节点的优先级降低,资源ip转移到备用节点node2上,再在客户端请求,发现后端web服务不受影响
# for i in {0..9};do curl http://10.1.252.73;done  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
   6.假如资源ip所在nginx调度器服务宕机或者出现故障了,这时,因为不是keepalived服务故障,所以资源ip时不会转移的。这时,我们就要保证在出现故障前把资源ip转移到备用nginx调度器上,所以,这里我们也可以再定义一个外部脚本来监控nginx服务,一旦出现故障就会调用脚本,降低其优先级然后转移资源ip到备用nginx调度器,如下:
# cat keepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   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 {             # 定义检测nginx的外部脚本
  
      script "killall -0 nginx && exit 0 || exit 1"# 如果检测到nginx服务在就返回0(为真),如果不在就返回值1(假)
  
      interval 1                  # 每隔1s检测一次
  
      weight -5                     # 优先级减5
  
}
  

  
vrrp_instance VI_1 {
  
    state MASTER
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 100
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736
  
    }
  
    track_script {
  
      chk_down
  chk_nginx      # 调用此脚本
  
    }
  

  
    notify_master "/etc/keepalived/notify.sh master"
  
    notify_backup "/etc/keepalived/notify.sh backup"
  
    notify_fault "/etc/keepalived/notify.sh fault"
  
}
  实验如下:
  1)现在资源ip在主节点node1上,此时访问资源ip可以正常响应;现在我们把node1上的nginx服务进程杀掉,再去访问,发现请求不到资源,资源ip也没有转移到备用节点node2,如下:

  2)在配置文件中,定义调用检查nginx服务的脚本后,我们再去做上面的实验,发现资源ip在停止服务前减低优先级,把资源ip转移到备用nginx调度器上,如下:
  杀掉node1的nginx服务,发现资源ip已经不在了

   请求服务,发现仍然可以访问
# for i in {0..9};do curl http://10.1.252.73;done  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  
RS 1
  
RS2 CentCOS 6.8
  查看备用nginx调度器node2,发现资源ip成功转移过来,如下:
  
  3)当一个节点nginx服务出现故障,我们就要立即去修复,或者重启服务,如果不想手动去修改,可以编辑通知脚本,在主节点变为MASTER和BACKUP都重启nginx服务,如下:
# cat 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
  
       systemctl restart nginx.service
  
       ;;
  
backup)
  
       notify backup
  
       systemctl restart nginx.service
  
       ;;
  
fault)
  
       notify fault
  
       ;;
  
*)
  
       echo "Usage: $(basename $0) {master|backup|fault}"
  
       exit 1
  
       ;;
  
esac
  现在我再把主节点的nginx服务kill掉,发现主节点资源ip转移到备用nginx节点node2,但是马上nginx服务就又启动起来了,资源ip又转移到主节点node1,如下:
# killall nginx # 杀掉node1的nginx服务  

  
# ip a l
  
1: lo:mtu 65536 qdisc noqueue state UNKNOWN
  
    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: eno16777736:mtu 1500 qdisc pfifo_fast state UP qlen 1000
  
    link/ether 00:0c:29:21:c9:43 brd ff:ff:ff:ff:ff:ff
  
    inet 10.1.252.161/16 brd 10.1.255.255 scope global eno16777736
  
       valid_lft forever preferred_lft forever
  
    inet6 fe80::20c:29ff:fe21:c943/64 scope link    # 资源ip转移
  
       valid_lft forever preferred_lft forever
  
# =====================================================================================
  

  
# ip a l
  
1: lo:mtu 65536 qdisc noqueue state UNKNOWN
  
    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: eno16777736:mtu 1500 qdisc pfifo_fast state UP qlen 1000
  
    link/ether 00:0c:29:21:c9:43 brd ff:ff:ff:ff:ff:ff
  
    inet 10.1.252.161/16 brd 10.1.255.255 scope global eno16777736
  
       valid_lft forever preferred_lft forever
  
    inet 10.1.252.73/16 scope global secondary eno16777736# 资源ip又被抢占回来了
  
       valid_lft forever preferred_lft forever
  
    inet6 fe80::20c:29ff:fe21:c943/64 scope link
  
       valid_lft forever preferred_lft forever
  查看node2的日志,也可以发现资源在短时间内转移了2次

  如上就是整个keepalived高可用nginx服务的整个过程。。。
  =============================================================================
  总结:
  1.keepalived高可用nginx主节点配置示例:

  2.高可用nginx通知脚本
#!/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
  
       systemctl restart nginx.service
  
       ;;
  
backup)
  
       notify backup
  
       systemctl restart nginx.service
  
       ;;
  
fault)
  
       notify fault
  
       ;;
  
*)
  
       echo "Usage: $(basename $0) {master|backup|fault}"
  
       exit 1
  
       ;;
  
esac
  3.高可用ipvs+dr主机点配置示例
# catkeepalived.conf  
! Configuration File for keepalived
  

  
global_defs {
  
   notification_email {
  
       root@localhost
  
   }
  
   notification_email_from keepalived@localhost
  
   smtp_server 127.0.0.1
  
   smtp_connect_timeout 30
  
   router_id node1
  
   vrrp_mcast_group4 224.0.100.19
  
}
  

  
vrrp_instance VI_1 {
  
    state MASTER
  
    interface eno16777736
  
    virtual_router_id 17
  
    priority 100
  
    advert_int 1
  
    authentication {
  
      auth_type PASS
  
      auth_pass f7111b2e
  
    }
  
    virtual_ipaddress {
  
      10.1.252.73/16 dev eno16777736# 要转移的资源ip
  
    }
  
    notify_master "/etc/keepalived/notify.sh master"# 调用通知脚本
  
    notify_backup "/etc/keepalived/notify.sh backup"
  
    notify_fault "/etc/keepalived/notify.sh fault"
  
}
  

  
virtual_server 10.1.252.73 80 {      # 定义转移资源ip上的集群服务
  
    delay_loop 3
  
    lb_algo rr
  
    lb_kind DR
  
    protocol TCP
  

  
    sorry_server 127.0.0.1 80          # 定义的 sorry_server为本机的80端口
  

  
    real_server 10.1.252.37 80 {       # 定义后端Real_server所提供的80服务
  
         weight 1
  HTTP_GET {
  url {
  path /
  status_code 200
  }
  connect_timeout 1
  nb_get_retry 3
  delay_before_retry 1
  }
  
    }
  
    real_server 10.1.252.153 80 {
  
         weight 1
  HTTP_GET {
  url {
  path /
  status_code 200
  }
  connect_timeout 1
  nb_get_retry 3
  delay_before_retry 1
  }
  
    }
  
}


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