第1章 LVS(负载均衡)+keepalived(高可用)

提示：接下来的实验又是一个新的开始，配置负载均衡不需要ipvsadm这个工具，因为keepalived本来就是另外一个自动管理工具。

1.1 负载均衡服务端配置

1.1.1 负载均衡服务器安装Keepalived

1.1.1.1 清理负载均衡信息

[root@lb01 ~]# ipvsadm -C
[root@lb01 ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn

1.1.1.2 安装keepalived

[root@lb01 ~]# yum install -y keepalived

1.1.2 配置keepalived单实例

1.1.2.1 lb01配置文件

[root@lb01 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id LVS_01
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24
    }
}

virtual_server 10.0.0.3 80 {        # 虚拟IP，来源于上面的虚拟IP地址，后面加空格加端口号
    delay_loop 6                    # 健康检查间隔，单位为秒
    lb_algo wrr                     # 负载均衡调度算法，一般用wrr、rr、wlc
    lb_kind DR                      # 负载均衡转发规则。一般包括DR,NAT,TUN 3种
    nat_mask 255.255.255.0
    persistence_timeout 50          # 会话保持时间。会话保持就是把用户请求转发给同一个服务器，否则刚在1上提交完帐号密码，就跳转到另一台服务器2上了
    protocol TCP                    # 转发协议，有TCP和UDP两种，一般用TCP，没用过UDP

    real_server 10.0.0.7 80 {       # 真实服务器，包括IP和端口号
        weight 1                    # 权重，数值越大，权重越高，被访问的概率越大
        TCP_CHECK {                 # 通过tcpcheck判断RealServer的健康状态
        connect_timeout 8           # 连接超时时间
        nb_get_retry 3              # 重连次数
        delay_before_retry 3        # 在重连前等待的时间
        connect_port 80             # 检测端口
        }
    }

    real_server 10.0.0.8 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
}

1.1.2.2 lb02配置文件

[root@lb02 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id LVS_02
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24
    }
}

virtual_server 10.0.0.3 80 {
    delay_loop 6         
    lb_algo wrr                
    lb_kind DR               
    nat_mask 255.255.255.0
    persistence_timeout 50    
    protocol TCP               

    real_server 10.0.0.7 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }

    real_server 10.0.0.8 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
}

1.1.3 检查配置情况

[root@lb01 ~]# systemctl start keepalived

[root@lb01 ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:7b:8b:0f brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.5/24 brd 10.0.0.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet 10.0.0.3/24 scope global secondary eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe7b:8b0f/64 scope link
       valid_lft forever preferred_lft forever

[root@lb01 ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.0.0.3:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0        
  -> 10.0.0.8:80                  Route   1      0          0

1.1.3.1 单实例配置文件对比

[root@lb01 ~]# diff keepalived-lb01.conf keepalived-lb02.conf
2c2
<    router_id LVS_01
---
>    router_id LVS_02
6c6
<     state MASTER
---
>     state BACKUP
9c9
<     priority 150
---
>     priority 100

1.1.4 多实例配置方案

1.1.4.1 lb01配置文件

[root@lb01 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id LVS_01
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 51
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24
    }
}

vrrp_instance VI_2 {
    state BACKUP
    interface eth0
    virtual_router_id 52
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 2222
    }
    virtual_ipaddress {
     10.0.0.4/24
    }
}

virtual_server 10.0.0.3 80 {
    delay_loop 6           
    lb_algo wrr                
    lb_kind DR               
    nat_mask 255.255.255.0
    persistence_timeout 50    
    protocol TCP   
            
    real_server 10.0.0.7 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }

    real_server 10.0.0.8 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
}

virtual_server 10.0.0.4 80 {
    delay_loop 6           
    lb_algo wrr               
    lb_kind DR               
    nat_mask 255.255.255.0
    persistence_timeout 50    
    protocol TCP               

    real_server 10.0.0.7 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }

    real_server 10.0.0.8 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
}

1.1.4.2 lb02配置文件

[root@lb02 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id LVS_02
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
     10.0.0.3/24
    }
}

vrrp_instance VI_2 {
    state MASTER
    interface eth0
    virtual_router_id 52
    priority 150
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 2222
    }
    virtual_ipaddress {
     10.0.0.4/24
    }
}

virtual_server 10.0.0.3 80 {
    delay_loop 6        
    lb_algo wrr               
    lb_kind DR               
    nat_mask 255.255.255.0
    persistence_timeout 50    
    protocol TCP               

    real_server 10.0.0.7 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }

    real_server 10.0.0.8 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
}

virtual_server 10.0.0.4 80 {
    delay_loop 6         
    lb_algo wrr               
    lb_kind DR               
    nat_mask 255.255.255.0
    persistence_timeout 50    
    protocol TCP               

    real_server 10.0.0.7 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }

    real_server 10.0.0.8 80 {
        weight 1             
        TCP_CHECK {
        connect_timeout 8      
        nb_get_retry 3
        delay_before_retry 3
        connect_port 80
        }
    }
}

1.1.4.3 查看lb01配置情况

[root@lb01 ~]# systemctl restart keepalived

[root@lb01 ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:7b:8b:0f brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.5/24 brd 10.0.0.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet 10.0.0.3/24 scope global secondary eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe7b:8b0f/64 scope link
       valid_lft forever preferred_lft forever

[root@lb01 ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.0.0.3:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0        
  -> 10.0.0.8:80                  Route   1      0          0        
TCP  10.0.0.4:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0        
  -> 10.0.0.8:80                  Route   1      0          0

1.1.4.4 查看lb02配置情况

[root@lb02 ~]# systemctl restart keepalived

[root@lb02 ~]# ip addr show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:06:04:d1 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.6/24 brd 10.0.0.255 scope global eth0
       valid_lft forever preferred_lft forever
    inet 10.0.0.4/24 scope global secondary eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe06:4d1/64 scope link
       valid_lft forever preferred_lft forever

[root@lb02 ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.0.0.3:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0        
  -> 10.0.0.8:80                  Route   1      0          0        
TCP  10.0.0.4:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0        
  -> 10.0.0.8:80                  Route   1      0          0

1.1.4.5 多实例配置文件对比

[root@lb01 ~]# diff keepalived-lb01-多实例.conf keepalived-lb02-多实例.conf
2c2
<    router_id LVS_01
---
>    router_id LVS_02
6c6
<     state MASTER
---
>     state BACKUP
9c9
<     priority 150
---
>     priority 100
21c21
<     state BACKUP
---
>     state MASTER
24c24
<     priority 100
---
>     priority 150

1.2 Web服务端配置

1.2.1 在lo网卡绑定VIP地址（ip）

[root@web01 ~]# ip addr add 10.0.0.3/32 dev lo

1.2.2 修改内核参数抑制ARP响应

[root@web01 ~]# cat >>/etc/sysctl.conf<<EOF
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
EOF
[root@web01 ~]# sysctl -p

1.3 Keepalive健康检查功能

Keepalived可以自动判断LVS代理的真实服务器存活情况，如果真实服务器发生宕机，Keepalived可以自动将宕机的服务器从LVS负载池中去除，当宕机的服务器重新启动后又会自动添加进LVS负载池中，这种检查功能叫做Keepalive健康检查。

1.3.1 关闭web01服务器

[root@web01 ~]# nginx -s stop

1.3.2 查看LVS情况

[root@lb01 ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.0.0.3:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0        
TCP  10.0.0.4:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0

1.3.3 开启Web01服务器

[root@web01 ~]# nginx

1.3.4 查看LVS情况

[root@lb01 ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.0.0.3:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0        
  -> 10.0.0.8:80                  Route   1      0          0        
TCP  10.0.0.4:80 wrr persistent 50
  -> 10.0.0.7:80                  Route   1      0          0        
  -> 10.0.0.8:80                  Route   1      0          0

第2章 LVS故障排错

排查过程：

首先通过客户端先访问真实服务器查看是否可以访问
再通过LVS服务器访问真实服务器查看是否可以访问
再通过客户端访问LVS访问真实服务器
最后通过正确的方法从头到尾梳理一遍安装过程，查看是否还有问题

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