Lvs+Keepalived+Bind+web构建高可用负载均衡系统
-------------------------------
一、前言
二、环境
三、配置
1.LB-Master及LB-Backup配置
(1)LB-Master及LB-Backup安装keepalived和ipvsadm
(2)LB-Master的keepalived主配置文档
(3)LB-Backup的keepalived主配置文档
2.DNS-Master及DNS-Backup配置
(1)DNS-Master及DNS-Backup网卡设置
(2)DNS-Master及DNS-Backup安装bind及ARP设置
(3)DNS-Master配置
(4)DNS-Backup配置
3.web1及web2配置
四、测试
五、故障模拟
模拟LB-Master失效
模拟DNS-Master失效
模拟web1失效
-------------------------------
一、前言
这个实验是实现企业高可用负载均衡的web案例，无论Master或Backup宕掉任意一台，业务照常可用。分析拓扑，其中LB-Master负责web的调度，LB-Master负责DNS的调度，实现负载均衡，如果其中一台出现故障，那么web和DNS服务会立即转移到另一台服务器上，DNS分为主辅同步，实现高可用，web在生产环境下页面应该是一致的，为了试验效果，web页面设置不一样，在实际环境下，web后端应架设共享存储，实现web页面的一致性。
二、环境
系统：CentOS6.4 32位 6台
拓扑图：
IP划分：
三、配置
1.LB-Master及LB-Backup配置
(1)LB-Master及LB-Backup安装keepalived和ipvsadm
# yum groupinstall "Additional Development" //安装开发工具 # yum groupinstall "Development tools" # tar -zxvf keepalived-1.2.1.tar.gz -C /usr/local/src/ # cd /usr/local/src/keepalived-1.2.1 # ./cnfigure Keepalived configuration ------------------------ Keepalived version : 1.2.1 Compiler : gcc Compiler flags : -g -O2 Extra Lib : -lpopt -lssl -lcrypto Use IPVS Framework : No //配置出现错误 IPVS sync daemon support : No Use VRRP Framework : Yes Use Debug flags : No 解决方法： # yum install kernel-devel ipvsadm # ln -s /usr/src/kernels/2.6.32-358.el6.i686/ /usr/src/linux # ./cnfigure //再次配置环境 # make //编译 # make install //安装 # cd /usr/local/etc //keepalived默认安装路径 # ll drwxr-xr-x. 3 root root 4096 May 24 00:37 keepalived drwxr-xr-x. 3 root root 4096 May 24 00:29 rc.d drwxr-xr-x. 2 root root 4096 May 24 00:29 sysconfig 配置以系统方式service启动 # cp /usr/local/etc/rc.d/init.d/keepalived /etc/rc.d/init.d/ # cp /usr/local/etc/sysconfig/keepalived /etc/sysconfig/ # mkdir /etc/keepalived # cp /usr/local/etc/keepalived/keepalived.conf /etc/keepalived/ # cp /usr/local/sbin/keepalived /usr/sbin/
(2)LB-Master的keepalived主配置文档
# cat /etc/keepalived/keepalived.conf
#guration File for keepalived
#global define
global_defs {
router_id Haweb_1
}
vrrp_sync_group VGM {
group {
VI_WEB
}
}
vrrp_sync_group VGN {
group {
HA_DNS
}
}
# vvrp_instance define #
vrrp_instance VI_WEB {
state MASTER
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 55
priority 100
advert_int 5
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.2.200/24 dev eth0
}
}
########## LVS ###########
virtual_server 192.168.2.200 80 {
delay_loop 6
lb_algo rr
lb_kind DR
# persistence_timeout 20
protocol TCP
real_server 192.168.2.50 80 {
weight 100
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.2.60 80 {
weight 100
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
### HA DNS START ###
vrrp_instance HA_DNS {
state BACKUP
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 56
priority 90
advert_int 5
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.2.100/24 dev eth0
}
}
########## LVS DNS ###########
virtual_server 192.168.2.100 53 {
delay_loop 6
lb_algo rr
lb_kind DR
# persistence_timeout 6
protocol UDP
real_server 192.168.2.30 53 {
weight 100
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 53
}
}
real_server 192.168.2.40 53 {
weight 100
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 53
}
}
}
##################################
(3)LB-Backup的keepalived主配置文档
# cat /etc/keepalived/keepalived.conf
#guration File for keepalived
#global define
global_defs {
router_id Haweb_1
}
vrrp_sync_group VGM {
group {
VI_WEB
}
}
vrrp_sync_group VGN {
group {
HA_DNS
}
}
# vvrp_instance define #
vrrp_instance VI_WEB {
state BACKUP
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 55
priority 90
advert_int 5
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.2.200/24 dev eth0
}
}
########## LVS ###########
virtual_server 192.168.2.200 80 {
delay_loop 6
lb_algo rr
lb_kind DR
# persistence_timeout 20
protocol TCP
real_server 192.168.2.50 80 {
weight 100
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
real_server 192.168.2.60 80 {
weight 100
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 80
}
}
}
### HA DNS START ###
vrrp_instance HA_DNS {
state MASTER
interface eth0
lvs_sync_daemon_inteface eth0
virtual_router_id 56
priority 100
advert_int 5
authentication {
auth_type PASS
auth_pass 123456
}
virtual_ipaddress {
192.168.2.100/24 dev eth0
}
}
########## LVS DNS ###########
virtual_server 192.168.2.100 53 {
delay_loop 6
lb_algo rr
lb_kind DR
# persistence_timeout 6
protocol UDP
real_server 192.168.2.30 53 {
weight 100
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 53
}
}
real_server 192.168.2.40 53 {
weight 100
TCP_CHECK {
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
connect_port 53
}
}
}
##################################
2.DNS-Master及DNS-Backup配置
(1)DNS-Master及DNS-Backup网卡设置
DNS-Master及DNS-Backup在各自网卡基础上再添加lo:0端口。
(2)DNS-Master及DNS-Backup安装bind及ARP设置
# yum install bind bind-chroot # vim /etc/sysctl.conf //添加以下两行 net.ipv4.conf.all.arp_announce = 2 //关闭所有接口的ARP响应和发布 net.ipv4.conf.all.arp_ignore = 1 # sysctl -p
(3)DNS-Master配置
# service named start Generating /etc/rndc.key: [ OK ] Starting named: [ OK ] # cd /var/named/chroot/etc/ # vim named.conf //编辑主配置文档
# vim named.rfc1912.zones //编辑区域声明文件[object Object]
# scp named.conf named.rfc1912.zones 192.168.2.40:/var/named/chroot/etc/ # cd /var/named/chroot/var/named/ # cp -p named.localhost abc.com.zone # cp -p named.localhost abc.com.local # vim abc.com.zone
# vim abc.com.local
(4)DNS-Backup配置
# cd /var/named/chroot/etc/ # chgrp named named.conf named.rfc1912.zones # vim named.rfc1912.zones
# service named start # cd /var/named/chroot/var/named/slaves # ll //区域文件已经同步 -rw-r--r--. 1 named named 325 May 27 19:31 abc.com.local -rw-r--r--. 1 named named 340 May 27 19:39 abc.com.zone # vim abc.com.zone
# vim abc.com.local
3.web1及web2配置
在原有网卡基础上再添加一块lo:0网卡
# yum install httpd # echo "This is web1.">/var/www/html/index.html //web1配置 # echo "This is web2.">/var/www/html/index.html //web2配置 # vim /etc/sysctl.conf //添加以下两行 net.ipv4.conf.all.arp_announce = 2 net.ipv4.conf.all.arp_ignore = 1 # sysctl -p # service httpd start
四、测试：
测试客户端IP配置：
客户端浏览器访问http://www.abc.com,并不断刷新，可以看出web1和web2交替不断出现，在实际生产环境下web内容是一样的 。
LB-Master（负责web轮询）：
# ipvsadm IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.2.200:http rr -> 192.168.2.50:http Route 100 0 4 -> 192.168.2.60:http Route 100 0 4 UDP 192.168.2.100:domain rr -> 192.168.2.30:domain Route 100 0 0 -> 192.168.2.40:domain Route 100 0 0 # ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link/ether 00:0c:29:1c:d4:8d brd ff:ff:ff:ff:ff:ff inet 192.168.2.10/24 brd 192.168.2.255 scope global eth0 inet 192.168.2.200/24 scope global secondary eth0 inet6 fe80::20c:29ff:fe1c:d48d/64 scope link valid_lft forever preferred_lft forever
LB-Backup（负责DNS轮询）：
IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.2.200:http rr -> 192.168.2.50:http Route 100 0 0 -> 192.168.2.60:http Route 100 0 0 UDP 192.168.2.100:domain rr -> 192.168.2.30:domain Route 100 0 6 -> 192.168.2.40:domain Route 100 0 6 # ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link/ether 00:0c:29:22:3d:01 brd ff:ff:ff:ff:ff:ff inet 192.168.2.20/24 brd 192.168.2.255 scope global eth0 inet 192.168.2.100/24 scope global secondary eth0 inet6 fe80::20c:29ff:fe22:3d01/64 scope link valid_lft forever preferred_lft forever
五、故障模拟
模拟LB-Master失效
（1）停掉LB-Master的keepalived服务
# service keepalived stop Stopping keepalived: [ OK ] # ipvsadm IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn # ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link/ether 00:0c:29:1c:d4:8d brd ff:ff:ff:ff:ff:ff inet 192.168.2.10/24 brd 192.168.2.255 scope global eth0 inet6 fe80::20c:29ff:fe1c:d48d/64 scope link valid_lft forever preferred_lft forever
（2）查看LB-Backup状态（不断在测试客户端刷新网页）
# ip addr 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 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 inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000 link/ether 00:0c:29:22:3d:01 brd ff:ff:ff:ff:ff:ff inet 192.168.2.20/24 brd 192.168.2.255 scope global eth0 inet 192.168.2.100/24 scope global secondary eth0 inet 192.168.2.200/24 scope global secondary eth0 inet6 fe80::20c:29ff:fe22:3d01/64 scope link valid_lft forever preferred_lft forever # ipvsadm IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.2.200:http rr -> 192.168.2.50:http Route 100 0 9 -> 192.168.2.60:http Route 100 0 10 UDP 192.168.2.100:domain rr -> 192.168.2.30:domain Route 100 0 6 -> 192.168.2.40:domain Route 100 0 6
2.模拟DNS-Master失效
（1）停掉DNS-Master的named服务，并恢复LB-Master的服务
# service named stop Stopping named: . [ OK ]
（2）查看LB-Master状态（不断在测试客户端刷新网页）
# ipvsadm IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.2.200:http rr -> 192.168.2.50:http Route 100 0 13 -> 192.168.2.60:http Route 100 0 14 UDP 192.168.2.100:domain rr -> 192.168.2.40:domain Route 100 0 0
（3）查看LB-Backup状态
# ipvsadm IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 192.168.2.200:http rr -> 192.168.2.50:http Route 100 0 0 -> 192.168.2.60:http Route 100 0 0 UDP 192.168.2.100:domain rr -> 192.168.2.40:domain Route 100 0 6
3.模拟web1失效
停掉web1的httpd服务即可测试，这步比较简单，不再赘述。