DNS服务部署（二）

实验步骤：

1.网络拓扑图

2.环境描述

服务器名称	IP地址
DNS服务器	192.168.1.107
web1	10.0.0.21（VIP:192.168.1.201)
web2	10.0.0.22（VIP:192.168.1.202)
web3	10.0.0.23（VIP:192.168.1.203)

3.部署三台web服务器

web1: 

[root@web1 ~]# cat /var/www/html/index.html 

web1 site 

web2:

[root@web2 ~]# cat /var/www/html/index.html

web2 site

[root@web3 ~]# cat  /var/www/html/index.html

web3 site

4.配置DNS服务实现DNS轮询功能

[root@dns-M named]# pwd

/var/named/chroot/var/named

[root@dns-M named]# cat pp.org.zone 

$TTL    86400

@               IN SOA  dns.pp.org.       root.pp.org. (

                                        201             ; serial (d. adams)

                                        3H              ; refresh

                                        15M             ; retry

                                        1W              ; expiry

                                        1D )            ; minimum

                IN NS           dns.pp.org.

                IN MX  10       mail.pp.org.

dns.pp.org      IN  A           192.168.1.107

www             IN A            192.168.1.201

www             IN A            192.168.1.202

www             IN A            192.168.1.203

5、结果测试

A.nslookup测试

[root@dns-M named]# nslookup 

> www.pp.org 

Server:         192.168.1.107

Address:        192.168.1.107#53

Name:   www.pp.org

Address: 192.168.1.201

Name:   www.pp.org

Address: 192.168.1.202

Name:   www.pp.org

Address: 192.168.1.203

B.访问域名测试

[root@dns-M named]# curl http://www.pp.org   

web2 site

[root@dns-M named]# curl http://www.pp.org

web1 site 

[root@dns-M named]# curl http://www.pp.org

web3 site

6.应用服务器之间高可用

   DNS轮询方式虽然可以实现负载均衡，但是并不能判断某台应用服务器在某一时刻是否可用，它只是将请求解析到应用服务器上。为了解决这个问题，可以用keepalived来实现应用服务器之间的高可用性。

1）网络拓扑图：

此时环境描述如下：

DNS：192.168.1.107 配置不变！

web服务器的IP修改为如下，且每个web服务器有一个VIP：  

web1:10.0.0.21（VIP:192.168.1.201)；

web2:10.0.0.22（VIP:192.168.1.202)；

web3:10.0.0.23（VIP:192.168.1.203)

2）应用服务器的keepalived配置

A、配置规划

编辑配置文件：

web1服务器的keepalived配置文件如下：

[root@web1 ~]# cat /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs {    notification_email {      [email protected]      [email protected]      [email protected]    }    notification_email_from [email protected]    smtp_server 192.168.200.1    smtp_connect_timeout 30    router_id web_1 } vrrp_instance VI_1 {     state MASTER     interface eth0     virtual_router_id 51     priority 150     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.201/24     } } vrrp_instance VI_2 {     state BACKUP     interface eth0     virtual_router_id 52     priority 100     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.202/24     } } vrrp_instance VI_3 {     state BACKUP     interface eth0     virtual_router_id 53     priority 50     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.203/24     } }

web2服务器的keepalived配置文件如下：

[root@web2 ~]# cat /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs {    notification_email {      [email protected]      [email protected]      [email protected]    }    notification_email_from [email protected]    smtp_server 192.168.200.1    smtp_connect_timeout 30    router_id web_1 } vrrp_instance VI_1 {     state BACKUP     interface eth0     virtual_router_id 51     priority 50     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.201/24     } } vrrp_instance VI_2 {     state MASTER     interface eth0     virtual_router_id 52     priority 150     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.202/24     } } vrrp_instance VI_3 {     state BACKUP     interface eth0     virtual_router_id 53     priority 100     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.203/24     } }

web3服务器的keepalived配置文件如下：

[root@web3 ~]# cat /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs {    notification_email {      [email protected]      [email protected]      [email protected]    }    notification_email_from [email protected]    smtp_server 192.168.200.1    smtp_connect_timeout 30    router_id web_1 } vrrp_instance VI_1 {     state BACKUP     interface eth0     virtual_router_id 51     priority 100     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.201/24     } } vrrp_instance VI_2 {     state BACKUP     interface eth0     virtual_router_id 52     priority 50     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.202/24     } } vrrp_instance VI_3 {     state MASTER     interface eth0     virtual_router_id 53     priority 150     advert_int 1     authentication {         auth_type PASS         auth_pass 1111     }     virtual_ipaddress {         192.168.1.203/24     } }

3）配置DNS轮询

[root@dns-M ~]# cat /var/named/chroot/var/named/pp.org.zone  $TTL    86400 @               IN SOA  dns.pp.org.       root.pp.org. (                                         201             ; serial (d. adams)                                         3H              ; refresh                                         15M             ; retry                                         1W              ; expiry                                         1D )            ; minimum                 IN NS           dns.pp.org.                 IN MX  10       mail.pp.org. dns.pp.org.     IN A             192.168.1.107 www             IN A            192.168.1.201 www             IN A            192.168.1.202 www             IN A            192.168.1.203

4）测试

依次启动web服务的keepalived服务

查看启动后的结果：

web1：

[root@web1 ~]# ip addr  1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue      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 qlen 1000     link/ether 00:0c:29:b7:f2:d0 brd ff:ff:ff:ff:ff:ff     inet 10.0.0.21/24 brd 10.0.0.255 scope global eth0     inet 192.168.1.201/24 scope global eth0     inet6 fe80::20c:29ff:feb7:f2d0/64 scope link         valid_lft forever preferred_lft forever 3: sit0: <NOARP> mtu 1480 qdisc noop      link/sit 0.0.0.0 brd 0.0.0.0

web2：

[root@web2 ~]# ip addr  1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue      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 qlen 1000     link/ether 00:0c:29:db:ef:b6 brd ff:ff:ff:ff:ff:ff     inet 10.0.0.22/24 brd 10.0.0.255 scope global eth0     inet 192.168.1.202/24 scope global eth0     inet6 fe80::20c:29ff:fedb:efb6/64 scope link         valid_lft forever preferred_lft forever 3: sit0: <NOARP> mtu 1480 qdisc noop      link/sit 0.0.0.0 brd 0.0.0.0

web3：

[root@web3 ~]# ip addr  1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue      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 qlen 1000     link/ether 00:0c:29:12:0a:ea brd ff:ff:ff:ff:ff:ff     inet 10.0.0.23/24 brd 10.0.0.255 scope global eth0     inet 192.168.1.203/24 scope global eth0     inet6 fe80::20c:29ff:fe12:aea/64 scope link         valid_lft forever preferred_lft forever 3: sit0: <NOARP> mtu 1480 qdisc noop      link/sit 0.0.0.0 brd 0.0.0.0

用curl命令查看结果：

[root@dns-M ~]# curl  http://www.pp.org web1 site  [root@dns-M ~]# curl  http://www.pp.org web3 site [root@dns-M ~]# curl  http://www.pp.org web2 site

注意：在实际工作中，三台web服务器的内容是一致的！！！

本文出自 “一点点” 博客，谢绝转载！