2、高性能web架构之DNS负载均衡（LVS-DR+keepalived实现DNS和web轮询）

LVS-DR+keepalived+DNS实现DNS高可用性：

一、介绍：

结合上一章的DNS主从复制，按现在大多数公司的需求是满足不了的。DNS配置虽然简单易用，但是它在网络中起到了主导作用。

如果客户端设置的这台首选DNS服务器刚好宕机，即使客户端还设置了备用DNS。还是会影响用户的上网速度，因为客户端使用首选DNS去解析，当首选DNS解析不了时，它会等待3秒才会去使用备用DNS。所以这里我要通过LVS-DR+keepalived实现DNS高可用性，也顺便把web的轮询也一起实现了：

LVS-DR+keepalived特点：

LVS负载均衡采用直连路由工作模式（LVS-DR），采用半开放的网络结构，结构与IP隧道模式类似，但各节点并不是分散在各地，而是与调度器位于同一个物理网络，负载调节器与各节点服务器通过本地网络连接，不需要建立专用的IP隧道。

Keepalived采用VRRP热备份协议，以软件的方式实现服务机的多机热备功能。其主要用来提供故障切换和健康检查功能——判断LVS负载调度器、节点服务器的可能性，及时隔离并替换为新的服务器，当故障主机恢复后将其重新加入群集。

部署：

1、网络拓扑：

2、环境描述：

系统描述

IP地址

作用

LVS-master

192.168.10.101

主备负载均衡器（同时做web和DNS调度）

LVS-backup

192.168.10.102

DNS-master

192.168.10.103

vip:192.168.10.66(主处理DNS轮询请求)

DNS-backup

192.168.10.104

Web节点组

192.168.10.105-106

vip:192.168.10.88（主处理web轮询请求）

环境准备（6台CentOS7.2系统）：

3、关闭防火墙\关闭SeLinux\设置时间同步（所有机器上操作）:

systemctl stop firewalld.service && systemctl disable firewalld.service

sed -i "s/SELINUX=enforcing/SELINUX=disabled/" /etc/selinux/config

setenforce 0

yum -y install wget net-tools ntp ntpdate lrzsz

systemctl restart ntpdate.service ntpd.service && systemctl enable ntpd.service ntpdate.service

4、配置主机映射/etc/hosts（下面是在LVS-master和LVS-backup操作）：

echo 192.168.10.101 linux-node1.server.com >> /etc/hosts

echo 192.168.10.102 linux-node2.server.com >> /etc/hosts

echo 192.168.10.103 linux-node3.server.com >> /etc/hosts

echo 192.168.10.104 linux-node4.server.com >> /etc/hosts

echo 192.168.10.105 linux-node5.server.com >> /etc/hosts

echo 192.168.10.106 linux-node6.server.com >> /etc/hosts

echo nameserver 192.168.10.66 >> /etc/resolv.conf //这里的DNS设置只是临时的，如果是生产环境，一定要在配置文件设置DNS

echo nameserver 192.168.10.103 >> /etc/resolv.conf

echo nameserver 192.168.10.104 >> /etc/resolv.conf

hostnamectl --static set-hostname linux-node1.server.com

bash

设置虚拟网卡（下面是在LVS-master和LVS-backup操作）：

[root@linux-node1 ~]# cd /etc/sysconfig/network-scripts/

[root@linux-node1 network-scripts]# cp ifcfg-eno16777736 ifcfg-eno16777736:0

[root@linux-node1 network-scripts]# cp ifcfg-eno16777736 ifcfg-eno16777736:1

[root@linux-node1 network-scripts]# cat ifcfg-eno16777736:0

TYPE=Ethernet

BOOTPROTO=static

NAME=eno16777736:0

UUID=682b8dd6-92e8-4d7b-aec2-f6bbc85533f8

DEVICE=eno16777736:0

ONBOOT=yes

IPADDR=192.168.10.66

NETMASK=255.255.255.0

[root@linux-node1 network-scripts]# cat ifcfg-eno16777736:1

TYPE=Ethernet

BOOTPROTO=static

NAME=eno16777736:0

UUID=682b8dd6-92e8-4d7b-aec2-f6bbc85533f8

DEVICE=eno16777736:0

ONBOOT=yes

IPADDR=192.168.10.88

NETMASK=255.255.255.0

[root@linux-node1 network-scripts]# systemctl restart network

[root@linux-node1 network-scripts]# ip add

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN

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: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

link/ether 00:0c:29:f9:b7:25 brd ff:ff:ff:ff:ff:ff

inet 192.168.10.101/24 brd 192.168.10.255 scope global eno16777736

valid_lft forever preferred_lft forever

inet 192.168.10.66/24 brd 192.168.10.255 scope global secondary eno16777736:0

valid_lft forever preferred_lft forever

inet6 fe80::20c:29ff:fef9:b725/64 scope link

valid_lft forever preferred_lft forever

[root@linux-node1 network-scripts]# tail -3 /etc/sysctl.conf

net.ipv4.conf.all.send_redirects = 0

net.ipv4.conf.default.send_redirects = 0

net.ipv4.conf.eno16777736.send_redirects = 0

[root@linux-node2 ~]# cd /etc/sysconfig/network-scripts/

[root@linux-node2 network-scripts]# cp ifcfg-eno16777736 ifcfg-eno16777736:0

[root@linux-node2 network-scripts]# cp ifcfg-eno16777736 ifcfg-eno16777736:1

[root@linux-node1 network-scripts]# cat ifcfg-eno16777736:0

TYPE=Ethernet

BOOTPROTO=static

NAME=eno16777736:0

UUID=682b8dd6-92e8-4d7b-aec2-f6bbc85533f8

DEVICE=eno16777736:0

ONBOOT=yes

IPADDR=192.168.10.66

NETMASK=255.255.255.0

[root@linux-node1 network-scripts]# cat ifcfg-eno16777736:1

TYPE=Ethernet

BOOTPROTO=static

NAME=eno16777736:1

UUID=682b8dd6-92e8-4d7b-aec2-f6bbc85533f8

DEVICE=eno16777736:1

ONBOOT=yes

IPADDR=192.168.10.88

NETMASK=255.255.255.0

[root@linux-node1 network-scripts]# systemctl restart network

[root@linux-node1 network-scripts]# ip add

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN

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: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

link/ether 00:0c:29:f9:b7:25 brd ff:ff:ff:ff:ff:ff

inet 192.168.10.101/24 brd 192.168.10.255 scope global eno16777736

valid_lft forever preferred_lft forever

inet 192.168.10.66/24 brd 192.168.10.255 scope global secondary eno16777736:0

valid_lft forever preferred_lft forever

inet 192.168.10.88/24 brd 192.168.10.255 scope global secondary eno16777736:1

valid_lft forever preferred_lft forever

inet6 fd05:fa56:9fbc::101/128 scope global tentative dynamic

valid_lft 86405sec preferred_lft 86405sec

inet6 fd05:fa56:9fbc:0:20c:29ff:fef9:b725/64 scope global tentative noprefixroute dynamic

valid_lft 7202sec preferred_lft 1802sec

inet6 fe80::20c:29ff:fef9:b725/64 scope link

valid_lft forever preferred_lft forever

[root@linux-node2 network-scripts]# tail -3 /etc/sysctl.conf

net.ipv4.conf.all.send_redirects = 0

net.ipv4.conf.default.send_redirects = 0

net.ipv4.conf.eno16777736.send_redirects = 0

最后都要sysctl -p

6、安装ipvsadm和keepalived（下面是在LVS-master和LVS-backup操作）：

[root@linux-node1 ~]# yum install ipvsadm -y

[root@linux-node2 ~]# yum install ipvsadm -y

[root@linux-node1 ~]# yum install keepalived -y

[root@linux-node2 ~]# yum install keepalived -y

[root@linux-node1 ~]# lsmod |grep ^ip_vs

ip_vs 140944 0

[root@linux-node2 ~]# lsmod |grep ^ip_vs

ip_vs 140944 0

[root@linux-node1 ~]# ipvsadm --save > /etc/sysconfig/ipvsadm #需要手动去添加这条才能启动

[root@linux-node2 ~]# ipvsadm --save > /etc/sysconfig/ipvsadm

[root@linux-node1 ~]# systemctl start ipvsadm && systemctl enable ipvsadm

[root@linux-node2 ~]# systemctl start ipvsadm && systemctl enable ipvsadm

7、开启路由转发并配置ipvsadm规则（下面是在LVS-master和LVS-backup操作）：

[root@linux-node1 ~]# echo 1 > /proc/sys/net/ipv4/ip_forward

[root@linux-node1 ~]# echo "options ip_vs conn_tab_bits=22" > /etc/modprobe.d/ip_vs.conf //lvs增加并发

[root@linux-node1 ~]# systemctl stop ipvsadm //先关闭ipvsadm，再添加53和80端口的规则

[root@linux-node1 ~]# ipvsadm -A -u 192.168.10.66:53 -s rr

[root@linux-node1 ~]# ipvsadm -a -u 192.168.10.66:53 -r 192.168.10.103 -g -w 1

[root@linux-node1 ~]# ipvsadm -a -u 192.168.10.66:53 -r 192.168.10.104 -g -w 1

[root@linux-node1 ~]# ipvsadm -A -t 192.168.10.88:80 -s rr

[root@linux-node1 ~]# ipvsadm -a -t 192.168.10.88:80 -r 192.168.10.105 -g -w 1

[root@linux-node1 ~]# ipvsadm -a -t 192.168.10.88:80 -r 192.168.10.106 -g -w 1

[root@linux-node1 ~]# ipvsadm --save > /etc/sysconfig/ipvsadm //保存规则，否则重启失效

[root@linux-node1 ~]# cat /etc/sysconfig/ipvsadm

-A -t 192.168.10.88:http -s rr

-a -t 192.168.10.88:http -r linux-node5.server.com:http -g -w 1

-a -t 192.168.10.88:http -r linux-node6.server.com:http -g -w 1

-A -u 192.168.10.66:domain -s rr

-a -u 192.168.10.66:domain -r linux-node3.server.com:domain -g -w 1

-a -u 192.168.10.66:domain -r linux-node4.server.com:domain -g -w 1

[root@linux-node1 ~]# systemctl start ipvsadm

[root@linux-node1 ~]# ipvsadm -L //查看调度规则

IP Virtual Server version 1.2.1 (size=4096)

Prot LocalAddress:Port Scheduler Flags

-> RemoteAddress:Port Forward Weight ActiveConn InActConn

TCP 192.168.10.88:http rr

-> linux-node5.server.com:http Route 1 0 0

-> linux-node6.server.com:http Route 1 0 0

UDP 192.168.10.66:domain rr

-> linux-node3.server.com:domai Route 1 0 0

-> linux-node4.server.com:domai Route 1 0 0

[root@linux-node2 ~]# echo 1 > /proc/sys/net/ipv4/ip_forward

[root@linux-node2 ~]# systemctl stop ipvsadm //先关闭ipvsadm，再添加53和80端口的规则

[root@linux-node2 ~]# ipvsadm -A -u 192.168.10.66:53 -s rr

[root@linux-node2 ~]# ipvsadm -a -u 192.168.10.66:53 -r 192.168.10.103 -g -w 1

[root@linux-node2 ~]# ipvsadm -a -u 192.168.10.66:53 -r 192.168.10.104 -g -w 1

[root@linux-node2 ~]# ipvsadm -A -t 192.168.10.88:80 -s rr

[root@linux-node2 ~]# ipvsadm -a -t 192.168.10.88:80 -r 192.168.10.105 -g -w 1

[root@linux-node2 ~]# ipvsadm -a -t 192.168.10.88:80 -r 192.168.10.106 -g -w 1

[root@linux-node2 ~]# ipvsadm --save > /etc/sysconfig/ipvsadm //保存规则，否则重启失效

[root@linux-node2 ~]# cat /etc/sysconfig/ipvsadm

-A -t 192.168.10.88:http -s rr

-a -t 192.168.10.88:http -r linux-node5.server.com:http -g -w 1

-a -t 192.168.10.88:http -r linux-node6.server.com:http -g -w 1

-A -u 192.168.10.66:domain -s rr

-a -u 192.168.10.66:domain -r linux-node3.server.com:domain -g -w 1

-a -u 192.168.10.66:domain -r linux-node4.server.com:domain -g -w 1

[root@linux-node2 ~]# systemctl start ipvsadm

[root@linux-node2 ~]# ipvsadm -L

IP Virtual Server version 1.2.1 (size=4096)

Prot LocalAddress:Port Scheduler Flags

-> RemoteAddress:Port Forward Weight ActiveConn InActConn

TCP 192.168.10.88:http rr

-> linux-node5.server.com:http Route 1 0 0

-> linux-node6.server.com:http Route 1 0 0

UDP 192.168.10.66:domain rr

-> linux-node3.server.com:domai Route 1 0 0

-> linux-node4.server.com:domai Route 1 0 0

注意：例如ipvsadm -A -t 192.168.10.88:80 -s rr（-A是添加-t是tcp协议rr是轮询。如果是udp协议，则-t换成-u：u代表udp的意思。）

8、配置LVS调度器keepalived的配置文件（下面是在LVS-master和LVS-backup操作）：

keepalived配置双vrrp instance，分别为：WEB实例和DNS实例。

8.1主LVS上keepalived的配置文件内容：

[root@linux-node1 ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

[root@linux-node1 ~]# cat /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs { # 全局设置

notification_email { # 设置报警邮件地址

[email protected]

}

notification_email_from abc@xx.com # 设置邮件的发送地址

smtp_server 192.168.200.1

smtp_connect_timeout 30

router_id LVS_TEST_R1 # 表示该台服务的ID

# vrrp_skip_check_adv_addr

# vrrp_strict

# vrrp_garp_interval 0

# vrrp_gna_interval 0

}

#================WEB-Instance start=====================

vrrp_instance VI_WEB { # vrrp 实例

state MASTER #master状态

interface eno16777736 #绑定vip在那个网卡

virtual_router_id 51 # master和backup的id一致

priority 100

advert_int 1 # master和backup之间的检测时间

authentication {

auth_type PASS

auth_pass yanyb

}

virtual_ipaddress {

192.168.10.88/24 # 设置虚拟IP

}

#=================config LVS-WEB======================

virtual_server 192.168.10.88 80 { # 设置虚拟服务器，ip端口以及花边号用逗号隔开

delay_loop 6 # 设置运行情况检查时间，单位是秒

lb_algo rr # 负载算法，这里是rr表示轮询

lb_kind DR # LVS工作机制，这里是DR模式

nat_mask 255.255.255.0

persistence_timeout 50 # 会话保持时间，单位是秒，这个选项对动态网页非常有帮助，为集群系统中的session共享提供了一个很好的解决方案，有了这个会话保持功能，用户的请求会被一直分发到某个服务节点，知道超过这个会话的保持时间，需要注意的是，这个会话保持时间是最大无响应的超时时间，in other words，用户在动态页面50秒以内没有执行任何操作，那么接下来的操作会重新调度到另一个节点上。如果一直在操作则不会影响

protocol TCP # 有TCP,UDP

real_server 192.168.10.105 80 { #设定真实服务器地址以及端口

weight 1 # 设置权重，数字越低，调度的比例越小。

TCP_CHECK {

connect_port 80

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

real_server 192.168.10.106 80 {

weight 1

TCP_CHECK {

connect_port 80

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

#================DNS-66 Instance start=====================

vrrp_instance VI_DNS {

state BACKUP

interface eno16777736

virtual_router_id 52

priority 90

advert_int 1

authentication {

auth_type PASS

auth_pass yanyb

}

virtual_ipaddress {

192.168.10.66/24

}

#==================config 66 LVS-DNS======================

virtual_server 192.168.10.66 53 {

delay_loop 3

lb_algo rr

lb_kind DR #（注这里有三种方式：NAT/DR/TUN）

nat_mask 255.255.255.0

persistence_timeout 50

protocol UDP

real_server 192.168.103 53 {

weight 100

MISC_CHECK {

connect_port 53

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

misc_path "/usr/bin/sh /etc/keepalived/check_dns_resolve.sh 192.168.10.103"

misc_timeout 5

}

real_server 192.168.104 53 {

weight 100

MISC_CHECK {

connect_port 53

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

misc_path "/usr/bin/sh /etc/keepalived/check_dns_resolve.sh 192.168.10.104"

misc_timeout 5

}

8.2、检测DNS的脚本：

[root@linux-node1 ~]# cat /etc/keepalived/check_dns_resolve.sh

#!/bin/bash

# check dns resolve

a_check="check.healthcheck.check"

ns_ip=$1

port=53

timeout=2

function EchoHelp(){

echo "use: ./check_dns_resolve.sh [ip] {port}"

exit 1

}

if [ $2 ]; then

port=$2

if [ $ns_ip -a $a_check ]; then

/usr/bin/nslookup -timeout=${timeout} -port=$port $a_check $ns_ip > /dev/null

else

EchoHelp

exit $?

[root@linux-node1 ~]# chmod +x /etc/keepalived/check_dns_resolve.sh

8.3、备LVS上keepalived的配置文件内容：

[root@linux-node2 ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

[root@linux-node2 ~]# cat /etc/keepalived/keepalived.conf

! Configuration File for keepalived

global_defs {

notification_email {

[email protected]

}

notification_email_from [email protected]

smtp_server 192.168.200.1

smtp_connect_timeout 30

router_id LVS_TEST_R2

# vrrp_skip_check_adv_addr

# vrrp_strict

# vrrp_garp_interval 0

# vrrp_gna_interval 0

}

#================WEB-Instance start=====================

vrrp_instance VI_WEB {

state BACKUP

interface eno16777736

virtual_router_id 51

priority 90

advert_int 1

authentication {

auth_type PASS

auth_pass yanyb

}

virtual_ipaddress {

192.168.10.88/24

}

#=================config LVS-WEB======================

virtual_server 192.168.10.88 80 {

delay_loop 6

lb_algo rr

lb_kind DR

nat_mask 255.255.255.0

# persistence_timeout 50

protocol TCP

real_server 192.168.10.105 80 {

weight 1

TCP_CHECK {

connect_port 80

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

real_server 192.168.10.106 80 {

weight 1

TCP_CHECK {

connect_port 80

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

#================DNSInstance start=====================

vrrp_instance VI_DNS {

state MASTER

interface eno16777736

virtual_router_id 52

priority 100

advert_int 1

authentication {

auth_type PASS

auth_pass yanyb

}

virtual_ipaddress {

192.168.10.66/24

}

#==================config LVS-DNS======================

virtual_server 192.168.10.66 53 {

delay_loop 3

lb_algo rr

lb_kind DR

nat_mask 255.255.255.0

# persistence_timeout 50

protocol UDP

real_server 192.168.103 53 {

weight 100

MISC_CHECK {

connect_port 53

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

misc_path "/usr/bin/sh /etc/keepalived/check_dns_resolve.sh 192.168.10.103"

misc_timeout 5

}

real_server 192.168.104 53 {

weight 100

MISC_CHECK {

connect_port 53

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

misc_path "/usr/bin/sh /etc/keepalived/check_dns_resolve.sh 192.168.10.103"

misc_timeout 5

}

8.4、检测DNS的脚本：

[root@linux-node2 ~]# cat /etc/keepalived/check_dns_resolve.sh

#!/bin/bash

# check dns resolve

a_check="check.healthcheck.check"

ns_ip=$1

port=53

timeout=2

function EchoHelp(){

echo "use: ./check_dns_resolve.sh [ip] {port}"

exit 1

}

if [ $2 ]; then

port=$2

if [ $ns_ip -a $a_check ]; then

/usr/bin/nslookup -timeout=${timeout} -port=$port $a_check $ns_ip > /dev/null

else

EchoHelp

exit $?

[root@linux-node2 ~]# chmod +x /etc/keepalived/check_dns_resolve.sh

9、配置LVS节点服务器脚本（WEB节点与DNS节点都要配置）

9.1 DNS节点的配置内容（主备DNS配置vip，并启动vip）：

[root@linux-node3 ~]# cat /etc/init.d/dns_vip.sh

#!/bin/bash

#description:config lvs-vip

vip=192.168.10.66

mask='255.255.255.255'

case $1 in

start)

echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore

echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore

echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce

echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce

sysctl -p >/dev/null 2>&1

/usr/sbin/ifconfig lo:0 $vip netmask $mask broadcast $vip up

/usr/sbin/route add -host $vip dev lo:0

echo "start VIP OK!!"

;;

stop)

/usr/sbin/ifconfig lo:0 down

/usr/sbin/route del $vip >/dev/null 2>&1

echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore

echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore

echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce

echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce

echo "stop VIP !!"

;;

echo "Usage $(basename $0) start|stop"

exit 1

;;

esac

[root@linux-node3 ~]# chmod +x /etc/init.d/dns_vip.sh

[root@linux-node3 ~]# /etc/init.d/dns_vip.sh start

start VIP OK!!

[root@linux-node3 ~]# ifconfig

eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500

inet 192.168.10.103 netmask 255.255.255.0 broadcast 192.168.10.255

inet6 fd05:fa56:9fbc::884 prefixlen 128 scopeid 0x0<global>

inet6 fe80::20c:29ff:fe67:a281 prefixlen 64 scopeid 0x20<link>

inet6 fd05:fa56:9fbc:0:20c:29ff:fe67:a281 prefixlen 64 scopeid 0x0<global>

ether 00:0c:29:67:a2:81 txqueuelen 1000 (Ethernet)

RX packets 25913 bytes 25518120 (24.3 MiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 20641 bytes 1782415 (1.6 MiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536

inet 127.0.0.1 netmask 255.0.0.0

inet6 ::1 prefixlen 128 scopeid 0x10<host>

loop txqueuelen 0 (Local Loopback)

RX packets 56 bytes 5854 (5.7 KiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 56 bytes 5854 (5.7 KiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo:0: flags=73<UP,LOOPBACK,RUNNING> mtu 65536

inet 192.168.10.66 netmask 255.255.255.255

loop txqueuelen 0 (Local Loopback

[root@linux-node4 ~]# /etc/init.d/dns_vip.sh start

start VIP OK!!

[root@linux-node4 ~]# ifconfig

docker0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500

inet 10.0.87.1 netmask 255.255.255.0 broadcast 0.0.0.0

ether 02:42:40:1f:12:0c txqueuelen 0 (Ethernet)

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

eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500

inet 192.168.10.104 netmask 255.255.255.0 broadcast 192.168.10.255

inet6 fd05:fa56:9fbc::eb8 prefixlen 128 scopeid 0x0<global>

inet6 fd05:fa56:9fbc:0:20c:29ff:feb4:91ca prefixlen 64 scopeid 0x0<global>

inet6 fe80::20c:29ff:feb4:91ca prefixlen 64 scopeid 0x20<link>

ether 00:0c:29:b4:91:ca txqueuelen 1000 (Ethernet)

RX packets 17149 bytes 15115091 (14.4 MiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 14432 bytes 1217454 (1.1 MiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536

inet 127.0.0.1 netmask 255.0.0.0

inet6 ::1 prefixlen 128 scopeid 0x10<host>

loop txqueuelen 0 (Local Loopback)

RX packets 65 bytes 6923 (6.7 KiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 65 bytes 6923 (6.7 KiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo:0: flags=73<UP,LOOPBACK,RUNNING> mtu 65536

inet 192.168.10.66 netmask 255.255.255.255

loop txqueuelen 0 (Local Loopback)

9.2、在区域配置文件添加A记录（主备DNS配置操作，如果DNS安装部署请看上一章）：

[root@linux-node3 ~]# cat /var/named/server.com.zone

$TTL 3600

@ SOA server.com. admin.server.com. (

2000 ; serial

1D ; refresh

1H ; retry

1W ; expire

3H ) ; minimum

@ IN NS linux-node3.server.com.

IN NS linux-node4.server.com.

linux-node3 IN A 192.168.10.103

linux-node4 IN A 192.168.10.104

abc IN A 192.168.10.104

vip IN A 192.168.10.66

[root@linux-node3 ~]# cat /var/named/10.168.192.arpa

$TTL 3600

@ SOA server.com. admin.server.com. (

2000 ; serial

1D ; refresh

1H ; retry

1W ; expire

3H ) ; minimum

IN NS linux-node3.server.com.

IN NS linux-node4.server.com.

103 IN PTR linux-node3.server.com.

104 IN PTR linux-node4.server.com.

104 IN PTR abc.server.com.

66 IN PTR vip.server.com.

[root@linux-node3 ~]#

[root@linux-node3 ~]# rndc reload #这里主从都reload

server reload successful

9.3、 WEB节点的配置内容(web的所有节点都配置vip，并启动vip)：

[root@linux-node5 ~]# cat /etc/init.d/web_vip.sh

#!/bin/bash

#description:config lvs-vip

vip=192.168.10.88

mask='255.255.255.255'

case $1 in

start)

echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore

echo 1 > /proc/sys/net/ipv4/conf/lo/arp_ignore

echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce

echo 2 > /proc/sys/net/ipv4/conf/lo/arp_announce

sysctl -p >/dev/null 2>&1

/usr/sbin/ifconfig lo:0 $vip netmask $mask broadcast $vip up

/usr/sbin/route add -host $vip dev lo:0

echo "start VIP OK!!"

;;

stop)

/usr/sbin/ifconfig lo:0 down

/usr/sbin/route del $vip >/dev/null 2>&1

echo 0 > /proc/sys/net/ipv4/conf/all/arp_ignore

echo 0 > /proc/sys/net/ipv4/conf/lo/arp_ignore

echo 0 > /proc/sys/net/ipv4/conf/all/arp_announce

echo 0 > /proc/sys/net/ipv4/conf/lo/arp_announce

echo "stop VIP !!"

;;

echo "Usage $(basename $0) start|stop"

exit 1

;;

esac

[root@linux-node5 ~]# chmod +x /etc/init.d/web_vip.sh

[root@linux-node5 ~]# /etc/init.d/web_vip.sh start

start VIP OK!!

[root@linux-node5 ~]# ifconfig

docker0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500

inet 10.0.20.1 netmask 255.255.255.0 broadcast 0.0.0.0

ether 02:42:49:62:01:b2 txqueuelen 0 (Ethernet)

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

eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500

inet 192.168.10.105 netmask 255.255.255.0 broadcast 192.168.10.255

inet6 fd05:fa56:9fbc:0:20c:29ff:fe80:dd8d prefixlen 64 scopeid 0x0<global>

inet6 fe80::20c:29ff:fe80:dd8d prefixlen 64 scopeid 0x20<link>

inet6 fd05:fa56:9fbc::a78 prefixlen 128 scopeid 0x0<global>

ether 00:0c:29:80:dd:8d txqueuelen 1000 (Ethernet)

RX packets 533 bytes 49113 (47.9 KiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 472 bytes 54298 (53.0 KiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536

inet 127.0.0.1 netmask 255.0.0.0

inet6 ::1 prefixlen 128 scopeid 0x10<host>

loop txqueuelen 0 (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

lo:0: flags=73<UP,LOOPBACK,RUNNING> mtu 65536

inet 192.168.10.88 netmask 255.255.255.255

loop txqueuelen 0 (Local Loopback)

[root@linux-node6 ~]# /etc/init.d/web_vip.sh start

start VIP OK!!

[root@linux-node6 ~]# ifconfig

eno16777736: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500

inet 192.168.10.106 netmask 255.255.255.0 broadcast 192.168.10.255

inet6 fe80::20c:29ff:fe7a:f77a prefixlen 64 scopeid 0x20<link>

inet6 fd05:fa56:9fbc::c36 prefixlen 128 scopeid 0x0<global>

inet6 fd05:fa56:9fbc:0:20c:29ff:fe7a:f77a prefixlen 64 scopeid 0x0<global>

ether 00:0c:29:7a:f7:7a txqueuelen 1000 (Ethernet)

RX packets 11472 bytes 15810540 (15.0 MiB)

RX errors 0 dropped 0 overruns 0 frame 0

TX packets 6340 bytes 477464 (466.2 KiB)

TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536

inet 127.0.0.1 netmask 255.0.0.0

inet6 ::1 prefixlen 128 scopeid 0x10<host>

loop txqueuelen 0 (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

lo:0: flags=73<UP,LOOPBACK,RUNNING> mtu 65536

inet 192.168.10.88 netmask 255.255.255.255

loop txqueuelen 0 (Local Loopback)

9.4、web节点都安装apche做测试(web的所有节点都操作）：

[root@linux-node5 ~]# yum -y install httpd

[root@linux-node5 ~]# echo “<h1>web1</h1>” > /var/www/html/index.html

[root@linux-node5 ~]# systemctl start httpd

[root@linux-node6 ~]# yum -y install httpd

[root@linux-node6 ~]# echo “<h1>web2</h1>” > /var/www/html/index.html

[root@linux-node6 ~]# systemctl start httpd

10、综合测试

测试之前要启动相关服务（keepalived、lvs节点脚本、节点Apache、节点DNS服务器等）

10.1、启动负载均衡调度器的keepalived服务（要确保DNS、DNS的vip；WEB、WEB的vip；还有ipvsadm这些服务都是正常启动的。）

[root@linux-node1 ~]# systemctl start keepalived

[root@linux-node2 ~]# systemctl start keepalived

10.2、web网页轮询测试：

然后验证：

10.3、DNS轮询测试，使用其中一个web当作客户端：

10.4、keepalived主从上vip切换测试：

再次启动后vip192.168.10.66又自动切回来，但是丢了一个包：

将node1的将node2的keepalived停掉：

Vip也可以切换过来：

OK到这里LVS-DR+keepalived实现DNS和web轮询就完成。

2、高性能web架构之DNS负载均衡（LVS-DR+keepalived实现DNS和web轮询）

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