通过一张张图走进DR
DR模式图解
简单拓扑图
为方便进行原理分析，将Client与群集机器放在同一网络中，数据包流经的路线为1-2-3-4
网络原理详解
DR中ARP遇到的问题
LVS-DR 负载均衡集群搭建
网络环境配置
| 一台调度器： | VM1：192.168.100:23 | 网关：不需要或者 192.168.100.1 |
|---|---|---|
| 二台WEB服务器集群池： | 192.168.100.24 | 网关：不需要或者 192.168.100.1 |
| 192.168.100.25 | 网关：不需要或者 192.168.100.1 | |
| 一台NFS共享服务器： | 192.168.100.21 | 192.168.100.1 |
| 虚拟VIP： | 192.168.100.88 | |
| 其他： | VM1网卡为仅主机模式 | 笔记本VM1 IP为：192.168.100.1 |
调度器配置：192.168.100.23
如果你是最小化安装 需要 yum -y install net-tools
我们要使用ifconfig这条命令，所有服务器全都要装
【1】配置虚拟IP地址（VIP）
[root@localhost ~]# cd /etc/sysconfig/network-scripts/
[root@localhost network-scripts]# cp ifcfg-ens33 ifcfg-ens33:0
[root@localhost network-scripts]# vi ifcfg-ens33:0
NAME=ens33:0
DEVICE=ens33:0
ONBOOT=yes
IPADDR=192.168.100.88
NETMASK=255.255.255.255
[root@localhost network-scripts]# ifup ifcfg-ens33:0
[root@localhost network-scripts]# ifconfig
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.100.23 netmask 255.255.255.0 broadcast 192.168.32.255
.....
ens33:0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500
inet 192.168.100.88 netmask 255.255.255.0 broadcast 192.168.32.255
ether 00:0c:29:9b:a7:cc txqueuelen 1000 (Ethernet)
#【2】调整/proc响应参数 对于 DR 群集模式来说，由于 LVS 负载调度器和各节点需要共用 VIP 地址，
#应该关闭 Linux 内核的重定向参数响应
服务器不是一台路由器，那么它不会发送重定向，所以可以关闭该功能
[root@localhost network-scripts]# vi /etc/sysctl.conf
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.ens33.send_redirects = 0
#生效
[root@localhost network-scripts]# sysctl -p
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.ens33.send_redirects = 0
【3】配置负载分配策略
[root@localhost /]# ipvsadm -v #检查内核是否支持
[root@localhost ~]#yum -y install ipvsadm
[root@localhost ~]# modprobe ip_vs
[root@localhost ~]# cat /proc/net/ip_vs
[root@localhost ~]#yum -y install ipvsadm
[root@localhost ~]# ipvsadm -A -t 192.168.100.88:80 -s rr
[root@localhost ~]# ipvsadm -a -t 192.168.100.88:80 -r 192.168.100.24:80 -g
[root@localhost ~]# ipvsadm -a -t 192.168.100.88:80 -r 192.168.100.25:80 -g
[root@localhost network-scripts]# ipvsadm-save > /opt/ipvsadm
[root@localhost ~]# systemctl start ipvsadm
[root@localhost network-scripts]# systemctl enable ipvsadm
配置存储服务器：192.168.100.21
rpm -q nfs-utils ###如果没装，yum -y install nfs-utils
rpm -q rpcbind ###如果没装，yum -y install rpcbind
###最好先启动rpcbind，不然有时会报错
[root@localhost ~]# systemctl restart rpcbind
[root@localhost ~]# systemctl start nfs
[root@localhost ~]# mkdir /opt/51xit /opt/52xit
[root@localhost ~]# echo "51是我" >/opt/51xit/index.html
[root@localhost ~]# echo "我是52" >/opt/52xit/index.html
[root@localhost ~]# vi /etc/exports
/opt/51xit 192.168.100.0/24(rw,sync)
/opt/52xit 192.168.100.0/24(rw,sync)
###最好先重启rpcbind，不然有时会报错
[root@localhost ~]# systemctl restart rpcbind
[root@localhost ~]# systemctl restart nfs
[root@localhost ~]# systemctl enable nfs
[root@localhost ~]# systemctl enable rpcbind
配置节点服务器：192.168.100.24
【1】配置虚拟IP地址
[root@localhost ~]# cd /etc/sysconfig/network-scripts/
[root@localhost network-scripts]# cp ifcfg-lo ifcfg-lo:0
[root@localhost network-scripts]# vi ifcfg-lo:0
DEVICE=lo:0
IPADDR=192.168.100.88
NETMASK=255.255.255.255
ONBOOT=yes
[root@localhost network-scripts]# ifup lo:0
[root@localhost network-scripts]# ifconfig
lo:0: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 192.168.100.10 netmask 255.255.255.255
loop txqueuelen 1000 (Local Loopback)
##添加本地访问路由，这个是一个脚本，相当于开机自动执行 route add -host 192.168.100.88 dev lo:0
[root@localhost network-scripts]# vi /etc/rc.local
/sbin/route add -host 192.168.100.88 dev lo:0
##手动先敲，敲完不能restart network，不然这个本地路由会消失，你需要重新添加
[root@localhost network-scripts]# route add -host 192.168.100.88 dev lo:0
[root@localhost network-scripts]# route -n
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.100.1 0.0.0.0 UG 100 0 0 ens33
192.168.100.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
192.168.100.88 0.0.0.0 255.255.255.255 UH 0 0 lo
【2】调整/proc响应参数
[root@localhost network-scripts]# vi /etc/sysctl.conf
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.default.arp_ignore = 1
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
#生效
[root@localhost network-scripts]# sysctl -p
【3】安装httpd 挂载测试页
[root@localhost ~]# showmount -e 192.168.100.21
Export list for 192.168.100.21:
/opt/52xit 192.168.100.0/24
/opt/51xit 192.168.100.0/24
[root@localhost ~]# yum -y install httpd
[root@localhost ~]# mount 192.168.100.21:/opt/51xit /var/www/html/
[root@localhost ~]# vi /etc/fstab
192.168.100.21:/opt/51xit /var/www/html/ nfs defaults,_netdev 0 0
[root@localhost ~]# systemctl start httpd
[root@localhost ~]# systemctl enable httpd
#登录192.168.100.24测试网站是否正常#
配置节点服务器：192.168.100.25
【1】配置虚拟IP地址
[root@localhost ~]# cd /etc/sysconfig/network-scripts/
[root@localhost network-scripts]# cp ifcfg-lo ifcfg-lo:0
[root@localhost network-scripts]# vi ifcfg-lo:0
DEVICE=lo:0
IPADDR=192.168.100.88
NETMASK=255.255.255.255
ONBOOT=yes
[root@localhost network-scripts]# ifup lo:0
[root@localhost network-scripts]# ifconfig
lo:0: flags=73<UP,LOOPBACK,RUNNING> mtu 65536
inet 192.168.100.10 netmask 255.255.255.255
loop txqueuelen 1000 (Local Loopback)
[root@localhost network-scripts]# vi /etc/rc.local
/sbin/route add -host 192.168.100.10 dev lo:0
[root@localhost network-scripts]# route add -host 192.168.100.88 dev lo:0
[root@localhost network-scripts]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.100.1 0.0.0.0 UG 100 0 0 ens33
192.168.100.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
192.168.100.88 0.0.0.0 255.255.255.255 UH 0 0 0 lo
【2】调整/proc响应参数
[root@localhost network-scripts]# vi /etc/sysctl.conf
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
net.ipv4.conf.default.arp_ignore = 1
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.lo.arp_ignore = 1
net.ipv4.conf.lo.arp_announce = 2
[root@localhost network-scripts]# sysctl -p
【2】安装httpd 挂载测试页
[root@localhost ~]# showmount -e 192.168.100.21
Export list for 192.168.100.44:
/opt/accp (everyone)
/opt/bdqn (everyone)
[root@localhost ~]# yum -y install httpd
[root@localhost ~]# mount 192.168.100.21:/opt/52xit /var/www/html/
[root@localhost ~]# vi /etc/fstab
192.168.100.21:/opt/52xit /var/www/html/ nfs defaults,_netdev 0 0
[root@localhost ~]# systemctl start httpd
[root@localhost ~]# systemctl enable httpd
#登录192.168.100.43测试网站是否正常#
访问测试
实验排错
####RPC--注册问题###
[root@localhost ~]# showmount -e
clnt_create: RPC: Program not registered
解决方案：
[root@localhost ~]# systemctl stop nfs
[root@localhost ~]# systemctl stop rpcbind
[root@localhost ~]# systemctl start rpcbind ###再次启动
[root@localhost ~]# systemctl start nfs
[root@localhost ~]# showmount -e
Export list for localhost.localdomain:
/opt/52xit 20.0.0.0/24
/opt/51xit 20.0.0.0/24
######问题： /etc/sysconfig/ipvsadm: No such ...ry####
解决方案：ipvsadm --save > /etc/sysconfig/ipvsadm
[root@localhost opt]# systemctl status ipvsadm.service ###查看ipvsadm是否工作正常
● ipvsadm.service - Initialise the Linux Virtual Server
Loaded: loaded (/usr/lib/systemd/system/ipvsadm.service; enabled; vendor preset: disabled)
Active: active (exited) since Mon 2020-09-21 23:47:17 EDT; 19min ago
Process: 18092 ExecStart=/bin/bash -c exec /sbin/ipvsadm-restore <
/etc/sysconfig/ipvsadm (code=exited, status=0/SUCCESS)
Main PID: 18092 (code=exited, status=0/SUCCESS)
CGroup: /system.slice/ipvsadm.service
#####问题：TCP 127.0.0.1:80 rr ###添加虚拟服务器数据异常###
[root@localhost ~]# ipvsadm -ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 127.0.0.1:80 rr ###添加虚拟服务器数据异常
-> 192.168.100.21:80 Route 1 0 0
-> 192.168.100.22:80 Route 1 0 0
###如何解决，清空重新添加###
ipvsadm -C
ipvsadm -A -t 192.168.100.100:80 -s rr
ipvsadm -a -t 192.168.100.100:80 -r 192.168.100.22:80 -g -w 1
ipvsadm -a -t 192.168.100.100:80 -r 192.168.100.23:80 -g -w 1
ipvsadm --save > /etc/sysconfig/ipvsadm