服务器IP地址ipvsadm命令详解LVS负载均衡调度算法虚拟服务实例一
添加一个虚拟服务查看lvs路由规则表查看目前ipvs调度状态删除为虚拟服务提供web功能的真实服务器虚拟服务规则表备份与还原 修改虚拟服务的调度算法 虚拟服务实例二
DR模式wrr NAT模式实验
原理关闭iptables和selinux编写执行脚本3更改所有realserver的网关为lvs的ip4测试
测试脚本
服务器IP地址
名称网络接口IP地址
lvseth2192.168.1.113lvseth1192.168.139.142web1eth0192.168.139.144web2eth0192.168.139.129web3eth0192.168.139.131
ipvsadm命令详解
ipvsadm 选项 服务器地址 -s 算法 ipvsadm 选项 服务器地址 -r 真实服务器地址 [工作模式] [ 权重]
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-A添加一个虚拟服务，使用IP地址、端口号，协议来唯一定义一个虚拟服务-E编辑一个虚拟服务-D删除一个虚拟服务-C清空虚拟服务表-R从标准输入中还原虚拟服务规则-S保存虚拟服务规则值标准输出，输出的规则可以使用-R导入还原-a在虚拟服务中添加一台真实服务器-e在虚拟服务中编辑一台真实服务器-d在虚拟服务中删除一台真实服务器-L显示虚拟服务列表-t使用TCP服务，该参数后需要跟主机与端口信息-u使用udp服务，该参数后需要跟主机与端口信息-s指定lvs的的调度算法-r设置真实服务器IP地址与端口信息-g设置lvs工作模式为DR直接路由模式-i设置lvs工作模式为TUN隧道模式-m设置lvs工作模式为NAT地址转换模式-w指定服务器的权重-c连接状态，配合-L使用-n数字格式输出
LVS负载均衡调度算法
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轮询调度RR加权轮询WRR最小连接调度LC加权最小连接WLC基于局部性最少的连接lblc带复制的基于局部性最少的连接lblcr目标地址散列调度DH源地址散列调度SH
虚拟服务实例一
添加一个虚拟服务
ipvsadm
-A -t 192.168.1.113:
80 -s rr
ipvsadm
-a -t 192.168.1.113:
80 -r 192.168.139.129:
80 -m
ipvsadm
-a -t 192.168.1.113:
80 -r 192.168.139.131:
80 -m
ipvsadm
-a -t 192.168.1.113:
80 -r 192.168.139.144:
80 -m
查看lvs路由规则表
# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-
> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.1.113:80 rr
-
> 192.168.139.129:80 Masq 1 0 0
-
> 192.168.139.131:80 Masq 1 0 0
-
> 192.168.139.144:80 Masq 1 0 0
查看目前ipvs调度状态
# ipvsadm -Lnc
删除为虚拟服务提供web功能的真实服务器
# ipvsadm -d -t 192.168.1.113:80 -r 192.168.139.144:80
# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-
> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.1.113:80 rr
-
> 192.168.139.129:80 Masq 1 0 0
-
> 192.168.139.131:80 Masq 1 0 0
虚拟服务规则表备份与还原
# ipvsadm -S > /tmp/ip_vs.bak ##备份规则表
# ls -l /tmp/ip_vs.bak
-
rw-r--r-- 1 root root 202 Jun 7 20:51 /tmp/ip_vs.bak
# ipvsadm -C ##清空规则表
# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-
> RemoteAddress:Port Forward Weight ActiveConn InActConn
#
# ipvsadm -R < /tmp/ip_vs.bak ## 从文件恢复
[root@centos6 ~]# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-
> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.1.113:80 rr
-
> 192.168.139.129:80 Masq 1 0 0
-
> 192.168.139.131:80 Masq 1 0 0
-
> 192.168.139.144:80 Masq 1 0 0
修改虚拟服务的调度算法
# ipvsadm -E -t 192.168.1.113:80 -s wrr
# ipvsadm -Ln
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-
> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 192.168.1.113:80 wrr
-
> 192.168.139.129:80 Masq 1 0 0
-
> 192.168.139.131:80 Masq 1 0 0
-
> 192.168.139.144:80 Masq 1 0 0
虚拟服务实例二
DR模式，wrr
# ipvsadm -A -t 192.168.1.113:80 -s wrr
# ipvsadm -a -t 192.168.1.113:80 -r 192.168.139.129:80 -g -w 1
# ipvsadm -a -t 192.168.1.113:80 -r 192.168.139.144:80 -g -w 2
# ipvsadm -e -t 192.168.1.113:80 -r 192.168.139.131:80 -g -w 3
# ipvsadm -Ln
IP Virtual Server version
1.2.1 (size=
4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP
192.168.1.113:
80 wrr
->
192.168.139.129:
80 Route
1 0 0
->
192.168.139.131:
80 Route
3 0 0
->
192.168.139.144:
80 Route
2 0 0
NAT模式实验
原理
1 关闭iptables和selinux
2 编写执行脚本
#!/bin/bash
echo 1 > /proc/sys/net/ipv4/ip_forward
echo 0 > /proc/sys/net/ipv4/conf/all/send_redirects
echo 0 > /proc/sys/net/ipv4/conf/default/send_redirects
echo 0 > /proc/sys/net/ipv4/conf/eth0/send_redirects
echo 0 > /proc/sys/net/ipv4/conf/eth1/send_redirects
/sbin/iptables -t nat -F
/sbin/iptables -t nat -X
/sbin/iptables -t nat -A POSTROUTING
-s 192.168.
139.0/
24 -j MASQUERADE
IPVSADM=
'/sbin/ipvsadm'
$IPVSADM -C
$IPVSADM -A -t
192.168.
1.199:
80 -s rr
$IPVSADM -a -t
192.168.
1.199:
80 -r
192.168.
139.254:
80 -m
$IPVSADM -a -t
192.168.
1.199:
80 -r
192.168.
139.253:
80 -m
$IPVSADM -a -t
192.168.
1.199:
80 -r
192.168.
139.252:
80 -m
3更改所有realserver的网关为lvs的ip
4测试
测试脚本
import requests
import time
def getHTMLText(url):
try:
r = requests.get(url)
r.raise_for_status()
r.encoding = r.apparent_encoding
return r.text
except:
return '产生异常'
if __name__ ==
"__main__":
url =
"http://192.168.1.199/"
for i
in range(
1000):
time.sleep(
2)
print(getHTMLText(url) + time.ctime())
tupdump监控的包的时间
tcpdump -nn -i eth0 tcp and port 80
and src host 192
.168.1.106
tcpdump:
verbose output suppressed,
use -v or -vv for full protocol decode
listening on eth0,
link-type EN10MB (
Ethernet),
capture size 65535
bytes
22
:44:44.674731 IP 192
.168.1.106.51729 > 192
.168.139.252.80:
Flags [S],
seq 2841949030,
win 8192,
options [mss 1460,nop,wscale 8,nop,nop,sackOK],
length 0
22
:44:44.675656 IP 192
.168.1.106.51729 > 192
.168.139.252.80:
Flags [.],
ack 1384177409,
win 2053,
length 0
22
:44:44.675736 IP 192
.168.1.106.51729 > 192
.168.139.252.80:
Flags [P.],
seq 0
:144,
ack 1,
win 2053,
length 144
22
:44:44.677485 IP 192
.168.1.106.51729 > 192
.168.139.252.80:
Flags [.],
ack 290,
win 2052,
length 0
22
:44:44.678669 IP 192
.168.1.106.51729 > 192
.168.139.252.80:
Flags [F.],
seq 144,
ack 290,
win 2052,
length 0
22
:44:46.698341 IP 192
.168.1.106.51730 > 192
.168.139.253.80:
Flags [S],
seq 692870389,
win 8192,
options [mss 1460,nop,wscale 8,nop,nop,sackOK],
length 0
22
:44:46.700948 IP 192
.168.1.106.51730 > 192
.168.139.253.80:
Flags [.],
ack 2177794250,
win 256,
length 0
22
:44:46.701147 IP 192
.168.1.106.51730 > 192
.168.139.253.80:
Flags [P.],
seq 0
:144,
ack 1,
win 256,
length 144
22
:44:46.704619 IP 192
.168.1.106.51730 > 192
.168.139.253.80:
Flags [.],
ack 290,
win 255,
length 0
22
:44:46.707583 IP 192
.168.1.106.51730 > 192
.168.139.253.80:
Flags [F.],
seq 144,
ack 290,
win 255,
length 0
22
:44:48.724503 IP 192
.168.1.106.51731 > 192
.168.139.254.80:
Flags [S],
seq 1622299946,
win 8192,
options [mss 1460,nop,wscale 8,nop,nop,sackOK],
length 0
22
:44:48.727207 IP 192
.168.1.106.51731 > 192
.168.139.254.80:
Flags [.],
ack 2671677042,
win 256,
length 0
22
:44:48.727433 IP 192
.168.1.106.51731 > 192
.168.139.254.80:
Flags [P.],
seq 0
:144,
ack 1,
win 256,
length 144
22
:44:48.731488 IP 192
.168.1.106.51731 > 192
.168.139.254.80:
Flags [.],
ack 290,
win 255,
length 0
22
:44:48.735640 IP 192
.168.1.106.51731 > 192
.168.139.254.80:
Flags [F.],
seq 144,
ack 290,
win 255,
length 0
python脚本执行结果的输出时间
web3:192.168.139.252
Wed Jun 7 22
:44:44 2017
web2:192.168.139.253
Wed Jun 7 22
:44:46 2017
web1:192.168.139.254
Wed Jun 7 22
:44:48 2017
web3:192.168.139.252
通过时间对比，显示时间是相同的。
