keepalive之LVS-DR架构

author：JevonWei
版权声明：原创作品

---

Keepalive实战之LVS-DR

实验目的：构建LVS-DR架构，为了达到LVS的高可用目的，故在LVS-DR的Director端做Keepalive集群，在Director-A上做keepalive-A，在Director上做keepalive-B，LVS-RS1和LVS-RS2为后端的两台web服务器，通过在Director上做keepalive集群实现高可用的目的

网络拓扑图

实验环境(keepalive节点同时作为LVS的directory节点)

keepalive-A(Director-A) 172.16.253.108
keepalive-B(Director-A) 172.16.253.105
LVS-RS1                 172.16.250.127
LVS-RS2                 172.16.253.193
VIP                     172.16.253.150
client                  172.16.253.177

LVS-RS web集群

为了更好的观察实验结果，故在此将RS1和RS2的web页面内容设置不一致，以致可以更清晰的区分RS1服务端和RS2服务端

LVS-RS1

[root@LVS-RS1 ~]# systemctl restart chronyd  \\多台服务器时间同步
[root@LVS-RS1 ~]# iptables -F
[root@LVS-RS1 ~]# setenforce 0
[root@LVS-RS1 ~]# yum -y install nginx
[root@LVS-RS1 ~]# vim /usr/share/nginx/html/index.html 
 Web RS1 
[root@LVS-RS1 ~]# systemctl start nginx

修改内核参数并添加VIP地址
[root@LVS-RS1 ~]# vim lvs_dr.sh
#!/bin/bash
#
vip=172.16.253.150
mask=255.255.255.255
iface="lo:0"

case $1 in
start)
    ifconfig $iface $vip netmask $mask broadcast $vip up
    route add -host $vip dev $iface
    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
    ;;
stop)
    echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
    echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
    echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
    echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
    ifconfig $iface down
    ;;
*)
    echo "Usage:$(basename $0) start|stop"
    exit 1
    ;;
esac
[root@LVS-RS1 ~]# bash lvs_dr.sh start
[root@LVS-RS1 ~]# ifconfig 
lo:0: flags=73  mtu 65536
    inet 172.16.253.150  netmask 255.255.255.255
    loop  txqueuelen 1  (Local Loopback)

LVS-RS2

[root@LVS-RS2 ~]# systemctl restart chronyd  \\多台服务器时间同步
[root@LVS-RS2 ~]# iptables -F
[root@LVS-RS2 ~]# setenforce 0
[root@LVS-RS2 ~]# yum -y install nginx
[root@LVS-RS2 ~]# vim /usr/share/nginx/html/index.html
 Web RS2 
[root@LVS-RS2 ~]# systemctl start nginx

修改内核参数并添加VIP地址
[root@LVS-RS2 ~]# vim lvs_dr.sh
#!/bin/bash
#
vip=172.16.253.150
mask=255.255.255.255
iface="lo:0"

case $1 in
start)
    ifconfig $iface $vip netmask $mask broadcast $vip up
    route add -host $vip dev $iface
    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
    ;;
stop)
    echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore
    echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore
    echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce
    echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce
    ifconfig $iface down
    ;;
*)
    echo "Usage:$(basename $0) start|stop"
    exit 1
    ;;
esac
[root@LVS-RS1 ~]# bash lvs_dr.sh start
[root@LVS-RS1 ~]# ifconfig 
lo:0: flags=73  mtu 65536
    inet 172.16.253.150  netmask 255.255.255.255
    loop  txqueuelen 1  (Local Loopback)

Keepalive集群

Director节点搭建

keepalive-A

[root@keepaliveA ~]# systemctl restart chronyd  \\多台服务器时间同步
[root@keepaliveA ~]# yum -y install ipvsadm

keepalive-B

[root@keepaliveB ~]# systemctl restart chronyd  \\多台服务器时间同步
[root@keepaliveB ~]# yum -y install ipvsadm

keepalive上配置web的sorry server

keepalive-A

[root@keepaliveA ~]# yum -y install nginx
[root@keepaliveA ~]# vim /usr/share/nginx/html/index.html 
 sorry from Director-A(keepalive-A) 
[root@keepaliveA ~]# systemctl start nginx

keepalive-B

[root@keepalive-B ~]# yum -y install nginx
[root@keepalive-B ~]# vim /usr/share/nginx/html/index.html 
 sorry from Director-B(keepalive-B) 
[root@keepaliveB ~]# systemctl start nginx

keepalive-A配置keepalive

keepalive-A

[root@keepalive-A ~]# iptables -F
[root@keepalive-A ~]# yum -y install keepalived
[root@keepaliveA ~]# vim /etc/keepalived/keepalived.conf
global_defs {  
    notification_email {  \\定义邮件通知设置
        [email protected]  \\定义邮件接收地址
    }
    notification_email_from [email protected] \\邮件发送者
    smtp_server 127.0.0.1 \\邮件server服务器
    smtp_connect_timeout 30  \\连接超时
    router_id keepaliveA \\route的ID信息，自定义
    vrrp_mcast_group4 224.103.5.5 \\多播地址段，默认为224.0.0.18 
}
vrrp_instance VI_A {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass qr8hQHuL
    }
virtual_ipaddress {
    172.16.253.150/32 dev ens33
}

virtual_server 172.16.253.150 80 {
    delay_loop 6  \\服务轮询的时间间隔
    lb_algo rr  \\定义调度方法；
    lb_kind DR  \\集群的类型；
    protocol TCP \\服务协议，仅支持TCP；
    sorry_server 127.0.0.1 80 \\指定sorry server，且为本机的wen服务提供的web页面
    
    real_server 172.16.250.127 80 {
        weight 1  \\权重
        SSL_GET {  \\应用层检测
            url {
                path /  \\定义要监控的URL
                #digest ff20ad2481f97b1754ef3e12ecd3a9cc \\判断上述检测机制为健康状态的响应的内容的校验码；
                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 1  \\重试之前的延迟时长
        }
    }
    real_server  172.16.253.193 80 {
        weight 1
        SSL_GET {
            url {
                path /
                #digest ff20ad2481f97b1754ef3e12ecd3a9cc 
                status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 1
        }
    }
}
[root@keepaliveA ~]# systemctl start keepalived 
[root@keepaliveA ~]# ip a l
2: ens33:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
     inet 172.16.253.150/32 scope global ens33
   valid_lft forever preferred_lft forever
[root@keepaliveA ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
    -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.16.253.150:80 rr
    -> 172.16.250.127:80            Route   1      0          0         
-> 172.16.253.193:80            Route   1      0          0   

keepalive-B配置keepalive

keepalive-B

[root@keepalive-B ~]# iptables -F
[root@keepalive-B ~]# yum -y install keepalived
[root@keepaliveA ~]# vim /etc/keepalived/keepalived.conf
global_defs {  
    notification_email {  \\定义邮件通知设置
        [email protected]  \\定义邮件接收地址
    }
    notification_email_from [email protected] \\邮件发送者
    smtp_server 127.0.0.1 \\邮件server服务器
    smtp_connect_timeout 30  \\连接超时
    router_id keepaliveA \\route的ID信息，自定义
    vrrp_mcast_group4 224.103.5.5 \\多播地址段，默认为224.0.0.18 
}
vrrp_instance VI_A {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 95
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass qr8hQHuL
    }
virtual_ipaddress {
    172.16.253.150/32 dev ens33
}

virtual_server 172.16.253.150 80 {
    delay_loop 6  \\服务轮询的时间间隔
    lb_algo rr  \\定义调度方法；
    lb_kind DR  \\集群的类型；
    protocol TCP \\服务协议，仅支持TCP；
    sorry_server 127.0.0.1 80 \\指定sorry server，且为本机的wen服务提供的web页面

    real_server 172.16.250.127 80 {
        weight 1  \\权重
        SSL_GET {  \\应用层检测
            url {
                path /  \\定义要监控的URL
                #digest ff20ad2481f97b1754ef3e12ecd3a9cc \\判断上述检测机制为健康状态的响应的内容的校验码；
                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 1  \\重试之前的延迟时长
        }
    }
    real_server  172.16.253.193 80 {
        weight 1
        SSL_GET {
            url {
                path /
                #digest ff20ad2481f97b1754ef3e12ecd3a9cc 
                status_code 200
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 1
        }
    }
}
[root@keepaliveB ~]# systemctl start keepalived 
[root@keepalive-B ~]# ipvsadm
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
    -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  172.16.253.150:http rr
    -> 172.16.250.127:http          Route   1      0          0         
    -> 172.16.253.193:http          Route   1      0          0     

访问测试

client测试

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
 Web RS1 
 Web RS2 
 Web RS1 
 Web RS2 
 Web RS1 

当keepalive-A故障时

[root@keepaliveA ~]# systemctl stop keepalived  

keepalive-B自动成为MASTER主节点，则LVS的director调度服务器切换为keepalive-B上，LVS-RS1和LVS-RS2的web服务正常使用

client访问测试

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
 Web RS2 
 Web RS1 
 Web RS2 
 Web RS1 
 Web RS2 

当keepalive-A修恢复正常时，keepalive-A再次成为MASTER主节点

[root@keepaliveA ~]# systemctl start keepalived
[root@keepaliveA ~]# ip a l
: ens33:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
link/ether 00:0c:29:75:dc:3c brd ff:ff:ff:ff:ff:ff
    inet 172.16.253.150/32 scope global ens33
   valid_lft forever preferred_lft forever

当LVS-RS1的web服务故障时

[root@LVS-RS1 ~]# iptables -A INPUT -p tcp --dport 80 -j REJECT 

client访问

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
 Web RS2 
 Web RS2 
 Web RS2 
 Web RS2 

当LVS-RS1和LVS-RS2的web服务全部故障时

[root@LVS-RS1 ~]# iptables -A INPUT -p tcp --dport 80 -j REJECT
[root@LVS-RS2 ~]# iptables -A INPUT -p tcp --dport 80 -j REJECT

client访问到的时sorry server服务器，且sorry server服务器为keepalive-A

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
 sorry from Director-A(keepalive-A)  
 sorry from Director-A(keepalive-A)  
 sorry from Director-A(keepalive-A)  
 sorry from Director-A(keepalive-A)  
 sorry from Director-A(keepalive-A)  

当keepalive-A故障时

[root@keepaliveA ~]# systemctl stop keepalived.service

client访问sorry server服务页面，且sorry server服务器为keepalive-B

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
 sorry from Director-B(keepalive-B) 
 sorry from Director-B(keepalive-B) 
 sorry from Director-B(keepalive-B) 
 sorry from Director-B(keepalive-B) 
 sorry from Director-B(keepalive-B) 

LVS-RS1的web服务恢复正常后

[root@LVS-RS1 ~]# iptables -F

client访问测试

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
 Web RS1 
 Web RS1 
 Web RS1 
 Web RS1 
 Web RS1 

LVS-RS1和LVS-RS2的web服务全部恢复正常后

[root@LVS-RS1 ~]# iptables -F  [root@LVS-RS2 ~]# iptables -F  

client访问测试

[root@client ~]# for i in {1..10};do curl http://172.16.253.150;done
 Web RS2 
 Web RS1 
 Web RS2 
 Web RS1 
 Web RS2 
    

保存及重载规则

保存：建议保存至/etc/sysconfig/ipvsadm

ipvsadm-save > /PATH/TO/IPVSADM_FILE
ipvsadm -S > /PATH/TO/IPVSADM_FILE
systemctl stop ipvsadm.service

重载：

ipvsadm-restore < /PATH/FROM/IPVSADM_FILE
ipvsadm -R < /PATH/FROM/IPVSADM_FILE
systemctl restart ipvsadm.service

keepalive节点通过DNS域名解析指向实现

获取web主页面内容的校验码

[root@keepaliveA ~]# genhash -s 172.16.250.127 -p 80 -u /