负载均衡之LVS-NAT LVS-DR模型详解
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LVS是Linux Virtual Server的缩写,是一个虚拟的服务器集群系统,能够定义一个或多个后端服务器。工作在INPUT上的内核中 ipvs。
LVS的调度方法:10种
静态方法:仅根据算法本身进行调度 rr: Round Robin 轮询 wrr: Weighted RR 权重轮询 sh: source hashing 根据 ip 反均衡 支持session绑定 dh: destination hashing 根据防火墙 设置时候 用到不多
动态方法:根据算法及RS当前的负载状况 真处在数据链接的叫活动状态 数据链接结束但为断开叫非活动链接 lc: Least Connection #最少连接 Overhead=Active*256+Inactive #开始时候是轮询 结果中,最小者胜出; wlc: Weighted LC Overhead=(Active*256+Inactive)/weight #结果中,最小者胜出; sed: Shortest Expect Delay #wlc的升级 最小期望延迟 Overhead=(Active+1)*256/weight nq: Nerver Queue #改进的sed 上来先轮一篇 不过是根据sed来轮询 lblc: Locality-based Least Connection 基于本地最少连接 dh+lc 用于session绑定 用的不多 lblcr: Replicated and Locality-based Least Connection 用的不多 后端是缓存服务器
lvs-nat
LVS NAT的特性: 1、RS应该使用私有地址; 2、RS的网关的必须指向DIP; 3、RIP和DIP必须在同一网段内; 4、请求和响应的报文都得经过Director;在高负载场景中,Director很可能成为系统性能瓶颈; 5、支持端口映射; 6、RS可以使用任意支持集群服务的OS;
安装ipvsadm
[[email protected] /]# yum install ipvsadm -y
vip:192.168.1.119
dip:192.168.243.132 虚拟网卡:主机模式
rip1:192.168.243.129 虚拟网卡:主机模式 http服务 测试页面demo.html页面内容martin
rip2:192.168.243.131 虚拟网卡:主机模式 http服务 测试页面demo.html页面内容lucia
http:这里不做安装配置说明
添加vip:
[[email protected] /]# ifconfig eth1:0 192.168.1.119/24 up
配置路由转发:
[[email protected] nat]# vim /etc/sysctl.conf net.ipv4.ip_forward = 1 [[email protected] nat]# sysctl -p
real-server路由指向dip:
[[email protected] /]# route add default gw 192.168.243.132 [[email protected] /]# route add default gw 192.168.243.132
添加集群服务:
#添加集群服务器 [[email protected] /]# ipvsadm -A -t 192.168.1.119:80 -s rr #添加后端服务器 [[email protected] /]# ipvsadm -a -t 192.168.1.119:80 -r 192.168.243.129 -m [[email protected] /]# ipvsadm -a -t 192.168.1.119:80 -r 192.168.243.131 -m #数据查看 [[email protected] /]# ipvsadm -L -n # --rate --stats IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.1.119:80 rr -> 192.168.243.129:80 Masq 1 0 0 -> 192.168.243.131:80 Masq 1 0 0
测试结果1:1
[[email protected] /]# ipvsadm -L -n --rate --stats IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Conns InPkts OutPkts InBytes OutBytes -> RemoteAddress:Port TCP 192.168.1.119:80 104 1090 507 154977 109894 -> 192.168.243.129:80 52 649 304 101371 75352 -> 192.168.243.131:80 52 441 203 53606 34542
修改:
[[email protected] /]# ipvsadm -E -t 192.168.1.119:80 -s wrr [[email protected] /]# ipvsadm -e -t 192.168.1.119:80 -r 192.168.243.131 -m -w 3
清空计数器:
[[email protected] /]# ipvsadm -Z -t 192.168.1.119:80
测试结果3:1
[[email protected] /]# ipvsadm -L -n IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.1.119:80 wrr -> 192.168.243.129:80 Masq 1 0 5 -> 192.168.243.131:80 Masq 3 1 16
数据保存:
[[email protected] lvs-date]# ipvsadm -S > /mydata/lvs-date/nat/wrr.conf
数据集群服务:
[[email protected] nat]# ipvsadm -D -t 192.168.1.119:80 [[email protected] nat]# ipvsadm -L -n IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn
还原集群服务:
[[email protected] nat]# ipvsadm -R </mydata/lvs-date/nat/wrr.conf [[email protected] nat]# ipvsadm -L -n IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.1.119:80 wrr -> 192.168.243.129:80 Masq 1 0 0 -> 192.168.243.131:80 Masq 3 0 0
查看映射表:
[[email protected] /]# ipvsadm -L -c IPVS connection entries pro expire state source virtual destination TCP 00:46 TIME_WAIT 192.168.1.102:56168 192.168.1.119:http 192.168.243.131:http TCP 00:45 TIME_WAIT 192.168.1.102:56161 192.168.1.119:http 192.168.243.129:http TCP 00:46 TIME_WAIT 192.168.1.102:56163 192.168.1.119:http 192.168.243.131:http TCP 00:46 TIME_WAIT 192.168.1.102:56164 192.168.1.119:http 192.168.243.131:http TCP 00:44 TIME_WAIT 192.168.1.102:56154 192.168.1.119:http 192.168.243.131:http TCP 00:45 TIME_WAIT 192.168.1.102:56162 192.168.1.119:http 192.168.243.131:http TCP 00:52 TIME_WAIT 192.168.1.102:56172 192.168.1.119:http 192.168.243.131:http TCP 00:46 TIME_WAIT 192.168.1.102:56165 192.168.1.119:http 192.168.243.129:http TCP 00:44 TIME_WAIT 192.168.1.102:56153 192.168.1.119:http 192.168.243.129:http TCP 00:47 TIME_WAIT 192.168.1.102:56171 192.168.1.119:http 192.168.243.131:http TCP 00:44 TIME_WAIT 192.168.1.102:56155 192.168.1.119:http 192.168.243.131:http TCP 00:46 TIME_WAIT 192.168.1.102:56167 192.168.1.119:http 192.168.243.131:http TCP 00:46 TIME_WAIT 192.168.1.102:56169 192.168.1.119:http 192.168.243.129:http TCP 00:47 TIME_WAIT 192.168.1.102:56170 192.168.1.119:http 192.168.243.131:http TCP 00:46 TIME_WAIT 192.168.1.102:56166 192.168.1.119:http 192.168.243.131:http TCP 00:45 TIME_WAIT 192.168.1.102:56159 192.168.1.119:http 192.168.243.131:http TCP 00:44 TIME_WAIT 192.168.1.102:56156 192.168.1.119:http 192.168.243.131:http TCP 00:44 TIME_WAIT 192.168.1.102:56152 192.168.1.119:http 192.168.243.131:http TCP 00:45 TIME_WAIT 192.168.1.102:56157 192.168.1.119:http 192.168.243.129:http TCP 00:45 TIME_WAIT 192.168.1.102:56160 192.168.1.119:http 192.168.243.131:http TCP 00:45 TIME_WAIT 192.168.1.102:56158 192.168.1.119:http 192.168.243.131:http TCP 00:44 TIME_WAIT 192.168.1.102:56149 192.168.1.119:http 192.168.243.131:http
lvs-dr:
LVS DR类型: 1、让前端路由将请求发往VIP时,只能是Dirctor上的VIP; 解决方案: (1) 静态地址绑定; 未必有路由器的配置权限; Director调用时静态地址绑定将难以适用; (2) arptables (3) 修改Linux内核参数,将RS上的VIP配置为lo接口的别名,限制Linux仅对对应接口的ARP请求做响应; LVS DR类型的特性: 1、RS可以使用私有地址;但也可以使用公网地址,此时可以直接通过互联网连入RS以实现配置、监控等; 2、RS的网关一定不能指向DIP; 3、RS跟Dirctory要在同一物理网络内(不能由路由器分隔); 4、请求报文经过Directory,但响应报文一定不经过Director 5、不支持端口映射; 6、RS可以使用大多数的操作系统;
vip:192.168.1.119
#dip: 虚拟网卡:主机模式
rip1:192.168.1.122 虚拟网卡:主机模式 http服务 测试页面demo.html页面内容martin
rip2:192.168.1.123 虚拟网卡:主机模式 http服务 测试页面demo.html页面内容lucia
http:这里不做安装配置说明
简单说明:这里的dip=vip vip是一般都是公网 假如要设置不同网段的dip,即dip可以是私网 只要rip与dip能通信 rip的网络能流向cip即可。
real-server:
[[email protected] ~]# echo 1 > /proc/sys/net/ipv4/conf/eth0/arp_ignore [[email protected] ~]# echo 2 > /proc/sys/net/ipv4/conf/eth0/arp_announce [[email protected] ~]# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore [[email protected] ~]# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce [[email protected] ~]# echo 1 > /proc/sys/net/ipv4/conf/eth0/arp_ignore [[email protected] ~]# echo 2 > /proc/sys/net/ipv4/conf/eth0/arp_announce [[email protected] ~]# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore [[email protected] ~]# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce arp_ignore 被动模式 # 是否响应ARP地址请求,默认0。 0 # 回复本机的所有ip地址(不管地址在哪里)。 1 # 仅在请求的目标地址配置请求到达的接口上的时候,才给予响应 arp_announce # 限制本机如何通告本地地址,默认0。 通告级别:主动模式 0 # 通高所有本机ip地址。 1 #试图仅向目标网络通告与其网络匹配的地址 2 # 仅对相同网络段地址进行通告。 通告rip mac 隐藏real-server上的vip mac
添加vip:(广播域设为本机)
[[email protected] ~]# ip addr add dev lo 192.168.1.119/32 broadcast 192.168.1.119 label lo:0 [[email protected] ~]# ip addr add dev lo 192.168.1.119/32 broadcast 192.168.1.119 label lo:0
添加集群服务
[[email protected] nat]# ipvsadm -A -t 192.168.1.119:80 -s rr #时间[-p 300] [[email protected] nat]# ipvsadm -a -t 192.168.1.119:80 -r 192.168.1.222 -g [[email protected] nat]# ipvsadm -a -t 192.168.1.119:80 -r 192.168.1.223 -g
[[email protected] nat]# ipvsadm -L -n IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.1.119:80 rr -> 192.168.1.222:80 Route 1 0 5 -> 192.168.1.223:80 Route 1 0 5
[[email protected] nat]# ipvsadm -E -t 192.168.1.119:80 -s wrr [[email protected] nat]# ipvsadm -e -t 192.168.1.119:80 -r 192.168.1.223 -g -w 4 [[email protected] nat]# ipvsadm -L -n IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.1.119:80 wrr -> 192.168.1.222:80 Route 1 0 6 -> 192.168.1.223:80 Route 4 0 24
抓包:数据从lo上出去
[[email protected] ~]# tcpdump -i any -nn -XX tcp src port 80 and ip src 192.168.1.119 tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on any, link-type LINUX_SLL (Linux cooked), capture size 65535 bytes 19:14:03.630672 IP 192.168.1.119.80 > 192.168.1.102.58761: Flags [S.], seq 4229184048, ack 1320608146, win 14480, options [mss 1460,sackOK,TS val 418789887 ecr 177960826,nop,wscale 6], length 0 0x0000: 0004 0001 0006 000c 2960 a9fd 0000 0800 ........)`...... 0x0010: 4500 003c 0000 4000 4006 b68e c0a8 0177 E..<[email protected]@......w 0x0020: c0a8 0166 0050 e589 fc14 3a30 4eb6 e192 ...f.P....:0N... 0x0030: a012 3890 69c0 0000 0204 05b4 0402 080a ..8.i........... 0x0040: 18f6 39ff 0a9b 777a 0103 0306 ..9...wz....
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