lvs：Linux Virtual Server
l4：四层交换，四层路由：
根据请求报文的目标IP和PORT将其转发至后端主机集群中的某一台主机（根据挑选算法）
lvs：
ipvsadm/ipvs
ipvsadm：用户空间的命令行工具，用于管理集群服务
ipvs：工作于内核中netfilter INPUT钩子上
支持TCP，UDP，AH，EST，AH_EST，SCTP等诸多协议
lvs type：
lvs-nat：masquerad
lvs-nat本质上就是多目标的DNAT（iptables lvs-nat模式通过修改请求报文的目标IP地址（同时可能会修改目标端口）至挑选出来的某RS的RIP地址实现转发
lvs-nat的特点：
RS和DIP应该使用私网地址，且RS的网关要指向DIP
请求和响应报文都要经由director转发，所以配置时需要将director的转发功能开启，极高负载的场景中，director可能会成为系统性能瓶颈
支持端口映射
RS可以使用任意OS
RS的RIP和Director的DIP必须在同一IP网络
lvs-dr（direct routing）：lvs的默认模式，gateway
lvs-dr模式通过修改请求报文的目标MAC地址进行转发
Director：调度器要配置VIP，DIP
RSs：所有的Real Server都要配置RIP，VIP
lvs-dr的特点：
保证前端路由器将目标IP为VIP的请求报文发送给director，解决方案有以下三种：
静态绑定
arptables
修改RS主机内核的2个参数：
arp_announce：是否接收并记录别人的通告以及是否通告自己的mac地址给别人。
arp_announce有三个可选值，0，1，2，其意义如下
0（default，默认值为0）：通告自己所拥有的所有地址
Nat模式
添加一块仅主机模式的网卡，一个是nat模式
[root@lvs ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:92:a3:46 brd ff:ff:ff:ff:ff:ff
inet 192.168.80.40/24 brd 192.168.80.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fe92:a346/64 scope link
valid_lft forever preferred_lft forever
3: ens37: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:92:a3:50 brd ff:ff:ff:ff:ff:ff
inet 192.168.121.129/24 brd 192.168.121.255 scope global dynamic noprefixroute ens37
valid_lft 1747sec preferred_lft 1747sec
inet6 fe80::17ce:4b6c:486a:5b69/64 scope link noprefixroute
valid_lft forever preferred_lft forever
//检查2快网卡IP[root@lvs network-scripts]# cp ifcfg-ens33 ifcfg-ens37
[root@lvs network-scripts]# ls
ifcfg-ens33 ifcfg-ens37
[root@lvs network-scripts]# vim ifcfg-ens37
TYPE=Ethernet
BOOTPROTO=static
NAME=ens37
DEVICE=ens37
ONBOOT=yes
IPADDR=192.168.121.129
NETMASK=255.255.255.0
//备注 ens37不用配置网关
[root@lvs ~]# ping www.baidu.com
PING www.a.shifen.com (14.215.177.39) 56(84) bytes of data.
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=1 ttl=128 time=26.7 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=2 ttl=128 time=34.8 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=3 ttl=128 time=26.4 ms
//可以ping通外网配置RS1
//在RS1上安装一个httpd
[root@RS1 ~]# apachectl start
[root@RS1 ~]# ss -antl
State Recv-Q Send-Q Local Address:Port Peer Address:Port Process
LISTEN 0 128 0.0.0.0:22 0.0.0.0:*
LISTEN 0 128 *:80 *:*
LISTEN 0 128 [::]:22 [::]:*
//启动它
[root@RS1 ~]# vi /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=static
NAME=ens33
DEVICE=ens33
ONBOOT=yes
IPADDR=192.168.80.20
NETMASK=255.255.255.0
GATEWAY=192.168.80.40
DNS1=114.114.114.114
//RS1的网关要指向lvs的IP40，重启网卡
//RS2提前安装好nginx并且启动
[root@RS2 ~]# vi /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=static
NAME=ens33
DEVICE=ens33
ONBOOT=yes
IPADDR=192.168.80.30
NETMASK=255.255.255.0
GATEWAY=192.168.80.40
DNS1=114.114.114.114
//网关也要指向lvs
[root@RS2 ~]# ifdown ens33;ifup ens33
//重启网卡配置lvs
[root@lvs ~]# vi /etc/sysctl.conf
# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
#
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
#
# For more information, see sysctl.conf(5) and sysctl.d(5).
net.ipv4.ip_forward = 1
//ip转发
[root@lvs ~]# sysctl -p
net.ipv4.ip_forward = 1
[root@lvs ~]# yum -y install ipvsadm
[root@lvs ~]# ipvsadm -A -t 192.168.121.129:80 -s rr
//指定vip轮回算法
[root@lvs ~]# ipvsadm -a -t 192.168.121.129:80 -r 192.168.80.20 -m
[root@lvs ~]# ipvsadm -a -t 192.168.121.129:80 -r 192.168.80.30 -m
//指向安装好httpd,nginx的RS1 RS2
[root@lvs ~]# ipvsadm -l
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP lvs:http rr
-> 192.168.80.20:http Masq 1 0 0
-> 192.168.80.30:http Masq 1 0 0[root@lvs ~]# ipvsadm -Sn > /etc/sysconfig/ipvsadm
[root@lvs ~]# cat /etc/sysconfig/ipvsadm
-A -t 192.168.121.129:80 -s rr
-a -t 192.168.121.129:80 -r 192.168.80.20:80 -m -w 1
-a -t 192.168.121.129:80 -r 192.168.80.30:80 -m -w 1
//更写配置文件接下来访问lvs 192.168.121.129
第一次访问刷新
再次刷新
这个是nat模式的配置用法
接下来把lvs调度器恢复快照，做DR模式
[root@lvs ~]# vi /etc/sysconfig/network-scripts/ifcfg-ens33
TYPE=Ethernet
BOOTPROTO=static
NAME=ens33
DEVICE=ens33
ONBOOT=yes
IPADDR=192.168.80.40
NETMASK=255.255.255.0
IPADDR1=192.168.80.100
NETMASK=255.255.255.0
GATEWAY=192.168.80.2
~
//配置ip
[root@lvs ~]# ifdown ens33;ifup ens33
Connection 'ens33' successfully deactivated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/1)
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/2)
[root@lvs ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:92:a3:46 brd ff:ff:ff:ff:ff:ff
inet 192.168.80.40/24 brd 192.168.80.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet 192.168.80.100/24 brd 192.168.80.255 scope global secondary noprefixroute ens33
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fe92:a346/64 scope link
valid_lft forever preferred_lft forever
//配置的2个ip都已经生效接下来吧RS1和RS2的网关配置成正常
[root@RS1 ~]# ping www.baidu.com
PING www.a.shifen.com (14.215.177.38) 56(84) bytes of data.
64 bytes from 14.215.177.38 (14.215.177.38): icmp_seq=1 ttl=128 time=22.4 ms
64 bytes from 14.215.177.38 (14.215.177.38): icmp_seq=2 ttl=128 time=23.3 ms
64 bytes from 14.215.177.38 (14.215.177.38): icmp_seq=3 ttl=128 time=23.5 ms
[root@RS2 ~]# ping www.baidu.com
PING www.a.shifen.com (14.215.177.39) 56(84) bytes of data.
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=1 ttl=128 time=25.5 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=2 ttl=128 time=26.1 ms
64 bytes from 14.215.177.39 (14.215.177.39): icmp_seq=3 ttl=128 time=34.2 ms
//配置完了重启网卡ping一下[root@RS1 ~]# vi /etc/sysctl.conf
# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
#
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
#
# For more information, see sysctl.conf(5) and sysctl.d(5).
net.ipv4.conf.all.arp_ignore = 1
ner.ipv4.conf.all.arp_announce = 2
[root@RS2 ~]# vi /etc/sysctl.conf
# sysctl settings are defined through files in
# /usr/lib/sysctl.d/, /run/sysctl.d/, and /etc/sysctl.d/.
#
# Vendors settings live in /usr/lib/sysctl.d/.
# To override a whole file, create a new file with the same in
# /etc/sysctl.d/ and put new settings there. To override
# only specific settings, add a file with a lexically later
# name in /etc/sysctl.d/ and put new settings there.
#
# For more information, see sysctl.conf(5) and sysctl.d(5).
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
[root@RS1 ~]# sysctl -p
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
//生效
[root@RS2 ~]# sysctl -p
net.ipv4.conf.all.arp_ignore = 1
net.ipv4.conf.all.arp_announce = 2
[root@RS1 ~]# ifconfig lo:0 192.168.80.100/32 broadcast 192.168.80.100 up
[root@RS1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet 192.168.80.100/0 brd 192.168.80.100 scope global lo:0
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:69:c4:93 brd ff:ff:ff:ff:ff:ff
inet 192.168.80.20/24 brd 192.168.80.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fe69:c493/64 scope link
valid_lft forever preferred_lft forever
[root@RS1 ~]# route add -host 192.168.80.100 dev lo
[root@RS1 ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.80.2 0.0.0.0 UG 100 0 0 ens33
192.168.80.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
192.168.80.100 0.0.0.0 255.255.255.255 UH 0 0 0 lo
[root@RS2 ~]# ifconfig lo:0 192.168.80.100/32 broadcast 192.168.80.100 up
[root@RS2 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet 192.168.80.100/0 brd 192.168.80.100 scope global lo:0
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
link/ether 00:0c:29:0d:53:85 brd ff:ff:ff:ff:ff:ff
inet 192.168.80.30/24 brd 192.168.80.255 scope global noprefixroute ens33
valid_lft forever preferred_lft forever
inet6 fe80::20c:29ff:fe0d:5385/64 scope link
valid_lft forever preferred_lft forever
[root@RS2 ~]# route add -host 192.168.80.100 dev lo
[root@RS2 ~]# route -n
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
0.0.0.0 192.168.80.2 0.0.0.0 UG 100 0 0 ens33
192.168.80.0 0.0.0.0 255.255.255.0 U 100 0 0 ens33
192.168.80.100 0.0.0.0 255.255.255.255 UH 0 0 0 lo[root@lvs~]# route add -host 192.168.80.100 dev ens33:0
[root@lvs ~]# yum -y install ipvsadm
[root@lvs ~]# ipvsadm -A -t 192.168.80.100:80 -s rr
[root@lvs ~]# ipvsadm -a -t 192.168.80.100:80 -r 192.168.80.20:80 -g
[root@lvs ~]# ipvsadm -a -t 192.168.80.100:80 -r 192.168.80.30:80 -g
[root@lvs ~]# ipvsadm -Ln
[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 192.168.80.100:80 rr
-> 192.168.80.20:80 Route 1 0 0
-> 192.168.80.30:80 Route 1 1 0
[root@lvs ~]# ipvsadm -Sn > /etc/sysconfig/ipvsadm
[root@lvs ~]# systemctl enable ipvsadm
[root@lvs ~]# echo "ipvsadm -R < /etc/sysconfig/ipvsadm" >>/etc/rc.d/rc.local
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