LVS跨网段DR模型配置
本次试验使用 5台 VMware 虚拟机搭建，Client 和 Router ens33网卡设置为桥接模式，其余网卡均为主机模式，各 ip 地址 规划如下：
一、各主机网络配置文件如下：
1.Client
[root@Client ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=none
IPADDR=6.6.6.6
NETMASK=255.255.255.0
GATEWAY=6.6.6.1
NAME=ens33
DEVICE=ens33
ONBOOT=yes[root@Client ~]# ifconfig
ens33: flags=4163 mtu 1500
inet 6.6.6.6 netmask 255.255.255.0 broadcast 6.6.6.255
inet6 fe80::20c:29ff:feec:ed4f prefixlen 64 scopeid 0x20
ether 00:0c:29:ec:ed:4f txqueuelen 1000 (Ethernet)
RX packets 4148 bytes 282249 (275.6 KiB)
RX errors 0 dropped 1 overruns 0 frame 0
TX packets 441 bytes 77912 (76.0 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73 mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1000 (Local Loopback)
RX packets 968 bytes 77720 (75.8 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 968 bytes 77720 (75.8 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 2.Router
[root@Router ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=none
IPADDR=6.6.6.1
NETMASK=255.255.255.0
NAME=ens33
DEVICE=ens33
ONBOOT=yes
[root@Router ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens37
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.0.1
NETMASK=255.255.255.0
NAME=ens37
DEVICE=ens37
ONBOOT=yes
[root@Router ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens37:0
TYPE=Ethernet
BOOTPROTO=none
IPADDR=9.9.9.1
NETMASK=255.255.255.0
NAME=ens37:0
DEVICE=ens37:0
ONBOOT=yes[root@Router ~]# ifconfig
ens33: flags=4163 mtu 1500
inet 6.6.6.1 netmask 255.255.255.0 broadcast 6.6.6.255
inet6 fe80::20c:29ff:fe49:d145 prefixlen 64 scopeid 0x20
ether 00:0c:29:49:d1:45 txqueuelen 1000 (Ethernet)
RX packets 2742 bytes 185080 (180.7 KiB)
RX errors 0 dropped 1 overruns 0 frame 0
TX packets 215 bytes 21219 (20.7 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens37: flags=4163 mtu 1500
inet 192.168.0.1 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 fe80::20c:29ff:fe49:d14f prefixlen 64 scopeid 0x20
ether 00:0c:29:49:d1:4f txqueuelen 1000 (Ethernet)
RX packets 2 bytes 303 (303.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 31 bytes 2358 (2.3 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens37:0: flags=4163 mtu 1500
inet 9.9.9.1 netmask 255.255.255.0 broadcast 9.9.9.255
ether 00:0c:29:49:d1:4f txqueuelen 1000 (Ethernet)
lo: flags=73 mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1000 (Local Loopback)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
3.LVS
[root@LVS ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.0.10
NETMASK=255.255.255.0
GATEWAY=192.168.0.1
NAME=ens33
DEVICE=ens33
ONBOOT=yes
[root@LVS ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33:0
TYPE=Ethernet
BOOTPROTO=none
IPADDR=9.9.9.9
NETMASK=255.255.255.0
NAME=ens33:0
DEVICE=ens33:0
ONBOOT=yes[root@LVS ~]# ifconfig
ens33: flags=4163 mtu 1500
inet 192.168.0.10 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 fe80::20c:29ff:feb8:7164 prefixlen 64 scopeid 0x20
ether 00:0c:29:b8:71:64 txqueuelen 1000 (Ethernet)
RX packets 182727 bytes 11437766 (10.9 MiB)
RX errors 0 dropped 64 overruns 0 frame 0
TX packets 10919 bytes 940289 (918.2 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
ens33:0: flags=4163 mtu 1500
inet 9.9.9.9 netmask 255.255.255.0 broadcast 9.9.9.255
ether 00:0c:29:b8:71:64 txqueuelen 1000 (Ethernet)
lo: flags=73 mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1000 (Local Loopback)
RX packets 2683 bytes 217652 (212.5 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2683 bytes 217652 (212.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 4.RS01
在RS服务器的还回口上配置vip之前，应先修改内核arp参数，禁止RS发出arp广播以及arp响应报文：
修改结果如下：
[root@RS01 ~]# cat /proc/sys/net/ipv4/conf/all/arp_ignore
1
[root@RS01 ~]# cat /proc/sys/net/ipv4/conf/lo/arp_ignore
1
[root@RS01 ~]# cat /proc/sys/net/ipv4/conf/all/arp_announce
2
[root@RS01 ~]# cat /proc/sys/net/ipv4/conf/lo/arp_announce
2[root@RS01 ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.0.11
NETMASK=255.255.255.0
GATEWAY=192.168.0.1
NAME=ens33
DEVICE=ens33
ONBOOT=yes
[root@RS01 ~]# cat /etc/sysconfig/network-scripts/ifcfg-lo:0
DEVICE=lo:0
NAME=lo:0
IPADDR=9.9.9.9
NETMASK=255.255.255.255
ONBOOT=yes[root@RS01 ~]# ifconfig
ens33: flags=4163 mtu 1500
inet 192.168.0.11 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 fe80::20c:29ff:fe3a:5119 prefixlen 64 scopeid 0x20
ether 00:0c:29:3a:51:19 txqueuelen 1000 (Ethernet)
RX packets 4304 bytes 354474 (346.1 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 2859 bytes 407104 (397.5 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73 mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1000 (Local Loopback)
RX packets 596 bytes 47240 (46.1 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 596 bytes 47240 (46.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo:0: flags=73 mtu 65536
inet 9.9.9.9 netmask 255.255.255.255
loop txqueuelen 1000 (Local Loopback) 5.RS02
[root@RS02 ~]# cat /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=none
IPADDR=192.168.0.12
NETMASK=255.255.255.0
GATEWAY=192.168.0.1
NAME=ens33
DEVICE=ens33
ONBOOT=yes
[root@RS02 ~]# cat /etc/sysconfig/network-scripts/ifcfg-lo:0
DEVICE=lo:0
NAME=lo:0
IPADDR=9.9.9.9
NETMASK=255.255.255.255
ONBOOT=yes[root@RS02 ~]# ifconfig
ens33: flags=4163 mtu 1500
inet 192.168.0.12 netmask 255.255.255.0 broadcast 192.168.0.255
inet6 fe80::20c:29ff:fedb:a51a prefixlen 64 scopeid 0x20
ether 00:0c:29:db:a5:1a txqueuelen 1000 (Ethernet)
RX packets 6266 bytes 514451 (502.3 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 3910 bytes 535357 (522.8 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73 mtu 65536
inet 127.0.0.1 netmask 255.0.0.0
inet6 ::1 prefixlen 128 scopeid 0x10
loop txqueuelen 1000 (Local Loopback)
RX packets 1454 bytes 118913 (116.1 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 1454 bytes 118913 (116.1 KiB)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo:0: flags=73 mtu 65536
inet 9.9.9.9 netmask 255.255.255.255
loop txqueuelen 1000 (Local Loopback)
6.网络连通性测试
在客户端 ping vip(9.9.9.9)
[root@Client ~]# ping -c 3 9.9.9.9
PING 9.9.9.9 (9.9.9.9) 56(84) bytes of data.
64 bytes from 9.9.9.9: icmp_seq=1 ttl=64 time=3.57 ms
64 bytes from 9.9.9.9: icmp_seq=2 ttl=64 time=0.834 ms
64 bytes from 9.9.9.9: icmp_seq=3 ttl=64 time=0.839 ms
--- 9.9.9.9 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2012ms
rtt min/avg/max/mdev = 0.834/1.748/3.572/1.289 ms
在RS上 ping 客户端
[root@RS01 ~]# ping -c 3 6.6.6.6
PING 6.6.6.6 (6.6.6.6) 56(84) bytes of data.
64 bytes from 6.6.6.6: icmp_seq=1 ttl=63 time=1.98 ms
64 bytes from 6.6.6.6: icmp_seq=2 ttl=63 time=1.25 ms
64 bytes from 6.6.6.6: icmp_seq=3 ttl=63 time=1.42 ms
--- 6.6.6.6 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2028ms
rtt min/avg/max/mdev = 1.258/1.555/1.980/0.311 ms二、在RS上安装httpd
[root@LVS ~]# curl 192.168.0.11
RS01
[root@LVS ~]# curl 192.168.0.12
RS02三、设置LVS调度规则
1.安装ipvsadm
[root@LVS ~]# yum install ipvsadm -y2.设置lvs规则
[root@LVS ~]# ipvsadm -A -t 9.9.9.9:80 -s rr
[root@LVS ~]# ipvsadm -a -t 9.9.9.9:80 -r 192.168.0.11:80 -g
[root@LVS ~]# ipvsadm -a -t 9.9.9.9:80 -r 192.168.0.12:80 -g
[root@LVS ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 9.9.9.9:80 rr
-> 192.168.0.11:80 Route 1 0 0
-> 192.168.0.12:80 Route 1 0 0 四、LVS调度测试
1.在LVS上访问测试
[root@LVS ~]# curl 9.9.9.9
^C结果：长时间无反应，
2.在client端访问测试
[root@Client ~]# curl 9.9.9.9
RS01
[root@Client ~]# curl 9.9.9.9
RS02
[root@Client ~]# curl 9.9.9.9
RS01
[root@Client ~]# curl 9.9.9.9
RS02LVS调度成功，工作正常！
五、LVS工作原理
在上面的调度测试中，为何在LVS上测试时长时间无反应？
LVS 的 IP 负载均衡技术是通过 ipvs 模块来实现的，ipvs 是 LVS 集群系统的核心软件，ipvs 工作于内核空间的 INPUT 链上。
当收到用户请求某集群服务时，经过 PREROUTING 链，经检查本机路由表，送往 INPUT 链；在进入 netfilter 的 INPUT 链时，ipvs 强行将请求报文通过 ipvsadm 定义的集群服务策略的路径改为 FORWORD 链，将报文转发至后端真实提供服务的主机。
所以在 LVS 上测试时，本机发出的请求，是直接从 OUTPUT 链流向 POSTROUTING 链，不会经由INPUT链，所以不会经过 ipvs 调度规则，因此长时间无反应。
六、设置LVS规则开机自动加载
将 ipvs 规则写进 /etc/sysconfig/ipvsadm 文件，到服务器宕机重启后，会自动加载。
ipvs 服务默认启动停止策略如下：
[root@LVS ~]# cat /usr/lib/systemd/system/ipvsadm.service
[Unit]
Description=Initialise the Linux Virtual Server
After=syslog.target network.target
[Service]
Type=oneshot
ExecStart=/bin/bash -c "exec /sbin/ipvsadm-restore < /etc/sysconfig/ipvsadm"
ExecStop=/bin/bash -c "exec /sbin/ipvsadm-save -n > /etc/sysconfig/ipvsadm"
ExecStop=/sbin/ipvsadm -C
RemainAfterExit=yes
[Install]
WantedBy=multi-user.target保存当前规则到文件：
[root@LVS ~]# ipvsadm-save -n > /etc/sysconfig/ipvsadm从文件中加载策略：
[root@LVS ~]# ipvsadm-restore < /etc/sysconfig/ipvsadm