Linux利用keepalived实现lvs的高可用性的操作方法

lvs+keepalived是什么？

keepalived工作原理

keepalived是集群管理中保证集群高可用的一个服务软件，其功能类似于heartbeat，用来防止单点故障。 keepalived是以VRRP协议为实现基础的，VRRP全称Virtual Router Redundancy Protocol，即虚拟路由冗余协议。 虚拟路由冗余协议，可以认为是实现路由器高可用的协议，即将N台提供相同功能的路由器组成一个路由器组，这个组里面有一个master和多个backup，master上面有一个对外提供服务的vip（该路由器所在局域网内其他机器的默认路由为该vip），master会发组播，当backup收不到vrrp包时就认为master宕掉了，这时就需要根据VRRP的优先级来选举一个backup当master。这样的话就可以保证路由器的高可用了。

LVS简介

LVS是Linux Virtual Server的简写，意即Linux虚拟服务器，是一个虚拟的服务器集群系统。本项目在1998年5月由章文嵩博士成立，是中国国内最早出现的自由软件项目之一。目前有三种IP负载均衡技术（VS/NAT、VS/TUN和VS/DR），十种调度算法。

本文重点给大家介绍Linux利用keepalived实现lvs的高可用性的操作方法，感兴趣的朋友参考下吧。

单主模型IPVS示例

配置keepalive

高可用的ipvs集群示例：修改keepalived配置文件

修改主机：192.168.234.27的keepalived配置文件

[root@234c27 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
notification_email {
root@localhost //接受邮件地址
}
notification_email_from keepalived@localhost //发送邮件地址
smtp_server 127.0.0.1 //发送邮件服务器IP
smtp_connect_timeout 30 //邮件连接超时时长
router_id kptwo //路由id
vrrp _mcast_group4 234.10.10.10 //指定vrrp协议的多播地址
}
vrrp_instance VI_1 { //vrrp协议的
state MASTER //lvs的MASTER服务器
interface ens37 //
virtual_router_id 50 //虚拟路由
priority 100 //权重为100.越大越先
advert_int 1 //发送组博包的间隔
authentication { //验证
auth_type PASS //方式为pass( 明文)
auth_pass 1111 //密码
}
virtual_ipaddress { //keepalived虚拟ip
10.0.0.100/24
}
}
virtual_server 10.0.0.100 80 {
 delay_loop 6 //检查后端服务器的时间间隔
 lb_algo wrr //定义调度方法
 lb_kind DR //集群的类型
 #persistence_timeout 50 //持久连接时长
 protocol TCP //服务协议，仅支持TCP
 real_server 192.168.234.47 80 { //后端real_server服务器地址
  weight 1 //权重
  HTTP_GET { //应用层检测
   url {
    path / //定义要监控的URL
    status_code 200 //判断上述检测机制为健康状态的响应码
   }
   connect_timeout 3 //连接请求的超时时长
   nb_get_retry 3 //重试次数
   delay_before_retry 3 //重试之前的延迟时长
  }
 }
 real_server 192.168.234.57 80 {
  weight 2
  HTTP_GET {
   url {
    path /
    status_code 200
   }
   connect_timeout 3
   nb_get_retry 3
   delay_before_retry 3
  }
 }
}

修改主机：192.168.234.37的keepalived配置文件

[root@234c37 ~]# vim /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 kptwo
 vrrp _mcast_group4 234.10.10.10
}
vrrp_instance VI_1 {
 state BACKUP
 interface ens37
 virtual_router_id 50
 priority 80
 advert_int 1
 authentication {
  auth_type PASS
  auth_pass 1111
 }
 virtual_ipaddress {
  10.0.0.100/24
 }
}
virtual_server 10.0.0.100 80 {
 delay_loop 6
 lb_algo wrr
 lb_kind DR
 #persistence_timeout 50
 protocol TCP
 sorry_server 127.0.0.1:80
 real_server 192.168.234.47 80 {
  weight 1
  HTTP_GET {
   url {
    path /
    status_code 200
   }
   connect_timeout 3
   nb_get_retry 3
   delay_before_retry 3
  }
 }
 real_server 192.168.234.57 80 {
  weight 2
  HTTP_GET {
   url {
    path /
    status_code 200
   }
   connect_timeout 3
   nb_get_retry 3
   delay_before_retry 3
  }
 }
}

查看keepalived

[root@234c37 ~]# systemctl status keepalived
● keepalived.service - LVS and VRRP High Availability Monitor
 Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled; vendor preset: disabled)
 Active: inactive (dead)
…………
[root@234c37 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
 -> RemoteAddress:Port   Forward Weight ActiveConn InActConn
//暂无ipvsadm

启动服务

[root@234c27 keepalived]# systemctl start keepalived.service
[root@234c27 keepalived]# systemctl status keepalived.service
● keepalived.service - LVS and VRRP High Availability Monitor
 Loaded: loaded (/usr/lib/systemd/system/keepalived.service; disabled; vendor preset: disabled)
 Active: active (running) since Fri 2018-08-31 20:30:02 CST; 12s ago
 Process: 9657 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS)
 Main PID: 9658 (keepalived)
………………
[root@234c27 keepalived]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
 -> RemoteAddress:Port   Forward Weight ActiveConn InActConn
TCP 10.0.0.100:80 wrr
 -> 192.168.234.47:80   Route 1  0   0
 -> 192.168.234.57:80   Route 2  0   0
//启动服务lvs vs已配置好

后端real_server准备

增加ip在网卡上 修改限制arp通告及应答级别 rs1 rs2都做，网关并指向路由

ip a a 10.0.0.100/32 dev ens37
echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore
echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore
echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce
route add default gw 192.168.234.17

安装httpd服务 写好网页文件

启动服务

image

多主模型IPVS示例

配置keepalive

高可用的ipvs集群示例：修改keepalived配置文件

修改主机：192.168.234.27的keepalived配置文件

[root@234c27 keepalived]# vim /etc/keepalived/keepalived.conf
global_defs {
  notification_email {
   root@localhost
  }
  notification_email_from keepalived@localhost
  smtp_server 127.0.0.1
  smtp_connect_timeout 30
  router_id kpone
  vrrp _mcast_group4 234.10.10.10
}
vrrp_instance VI_1 {
  state MASTER
  interface ens37
  virtual_router_id 50
  priority 100
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  virtual_ipaddress {
    10.0.0.100/24
  }
}
vrrp_instance VI_2 {
  state BACKUP
  interface ens37
  virtual_router_id 51
  priority 80
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 2222
  }
  virtual_ipaddress {
    10.0.0.200/24
  }
}
virtual_server 10.0.0.100 80 {
  delay_loop 6
  lb_algo wrr
  lb_kind DR
  #persistence_timeout 50
  protocol TCP
  #sorry_server 127.0.0.1:80
  real_server 192.168.234.47 80 {
    weight 1
    HTTP_GET {
      url {
       path /
       status_code 200
      }
      connect_timeout 3
      nb_get_retry 3
      delay_before_retry 3
    }
  }
}
virtual_server 10.0.0.200 80 {
  delay_loop 6
  lb_algo wrr
  lb_kind DR
  #persistence_timeout 50
  protocol TCP
  #sorry_server 127.0.0.1:80
  real_server 192.168.234.57 80 {
    weight 1
    HTTP_GET {
      url {
       path /
       status_code 200
      }
      connect_timeout 3
      nb_get_retry 3
      delay_before_retry 3
    }
  }
}

修改主机：192.168.234.37的keepalived配置文件

[root@234c37 ~]# vim /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 kptwo
  vrrp _mcast_group4 234.10.10.10
}
vrrp_instance VI_1 {
  state BACKUP
  interface ens37
  virtual_router_id 50
  priority 80
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 1111
  }
  virtual_ipaddress {
    10.0.0.100/24
  }
}
vrrp_instance VI_2 {
  state MASTER
  interface ens37
  virtual_router_id 51
  priority 100
  advert_int 1
  authentication {
    auth_type PASS
    auth_pass 2222
  }
  virtual_ipaddress {
    10.0.0.200/24
  }
}
virtual_server 10.0.0.100 80 {
  delay_loop 6
  lb_algo wrr
  lb_kind DR
  #persistence_timeout 50
  protocol TCP
  #sorry_server 127.0.0.1:80
  real_server 192.168.234.47 80 {
    weight 1
    HTTP_GET {
      url {
       path /
       status_code 200
      }
      connect_timeout 3
      nb_get_retry 3
      delay_before_retry 3
    }
  }
}
virtual_server 10.0.0.200 80 {
  delay_loop 6
  lb_algo wrr
  lb_kind DR
  #persistence_timeout 50
  protocol TCP
  #sorry_server 127.0.0.1:80
  real_server 192.168.234.57 80 {
    weight 1
    HTTP_GET {
      url {
       path /
       status_code 200
      }
      connect_timeout 3
      nb_get_retry 3
      delay_before_retry 3
    }
  }
}

让10.0.0.100的ip优先分配至192.168.234.47 192.168.234.57备用

让10.0.0.200的ip优先分配至192.168.234.57 192.168.234.47备用

后端real_server准备

修改192.168.234.57的vip为10.0.0.200/32

  [root@234c27 keepalived]# ipvsadm -Ln
  IP Virtual Server version 1.2.1 (size=4096)
  Prot LocalAddress:Port Scheduler Flags
   -> RemoteAddress:Port      Forward Weight ActiveConn InActConn
  TCP 10.0.0.100:80 wrr
   -> 192.168.234.47:80      Route  1   0     0
  TCP 10.0.0.200:80 wrr
  -> 192.168.234.57:80      Route  1   0     0

现在宕掉一个lvs

  [root@234c27 keepalived]# systemctl stop keepalived.service
  [root@234c27 keepalived]# ipvsadm -Ln
  IP Virtual Server version 1.2.1 (size=4096)
  Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port      Forward Weight ActiveConn InActConn

依然提供服务

 [root@234c37 ~]# ipvsadm -Ln
 IP Virtual Server version 1.2.1 (size=4096)
  Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port      Forward Weight ActiveConn InActConn
  TCP 10.0.0.100:80 wrr
   -> 192.168.234.47:80      Route  1   0     21
  TCP 10.0.0.200:80 wrr
   -> 192.168.234.57:80      Route  1   0     39

后一个实现基于前一个的基础上修改来的

假设要实现sorry_server

1.把rs服务都停掉。然后在lvs上安装apache或者nginx服务

2.将keepalived配置文件中的

virtual_server 10.0.0.200 80 {
  delay_loop 6
  lb_algo wrr
  lb_kind DR
  #persistence_timeout 50
  protocol TCP
  #sorry_server 127.0.0.1:80 //这一行来修改 写出服务出错之后的页面
  real_server 192.168.234.57 80 {
    weight 1
    HTTP_GET {
      url {
       path /
       status_code 200
      }
      connect_timeout 3
      nb_get_retry 3
      delay_before_retry 3
    }
  }
}