redhat配置dns服务器bind

配置Oracle11g的RAC需要使用DNS服务器来解析SCAN IP，本文就是以此为例介绍bind服务器的使用。首先科普一下bind服务器,属于企业级产品了，还是开源的：

Bind是Berkeley Internet Name Domain Service的简写，它是一款实现DNS服务器的开放源码软件。Bind原本是美国DARPA资助伯克利大学（Berkeley）开设的一个研究生课题，后来经过多年的变化发展，已经成为世界上使用最为广泛的DNS服务器软件，目前Internet上半数以上的DNS服务器有都是用Bind来架设的。参考文档:http://www.cnblogs.com/luoahong/p/7859000.html

内网使用的简单场合就使用基本的功能足够了。要使用内网的dns服务器解析，每个主机都有配置本地的服务器。linux中的配置就在/etc/resolv.conf文件修改。配置方法参考下面：

/etc/resolv.conf

该文件是DNS域名解析的配置文件，它的格式很简单，每行以一个关键字开头，后接配置参数。
resolv.conf的关键字主要有四个，分别是：
nameserver  #定义DNS服务器的IP地址
domain  #定义本地域名
search  #定义域名的搜索列表
sortlist  #对返回的域名进行排序

详细说明：
nameserver　表明DNS服务器的IP地址。可以有很多行的nameserver，每一个带一个IP地址。在查询时就按nameserver在本文件中的顺序进行，
且只有当第一个nameserver没有反应时才查询下面的nameserver。

domain　  声明主机的域名。很多程序用到它，如邮件系统；当为没有域名的主机进行DNS查询时，也要用到。
如果没有域名，主机名将被使用，删除所有在第一个点( .)前面的内容。

search　　　它的多个参数指明域名查询顺序。当要查询没有域名的主机，主机将在由search声明的域中分别查找。
domain和search不能共存；如果同时存在，后面出现的将会被使用。

sortlist　　 允许将得到域名结果进行特定的排序。它的参数为网络/掩码对，允许任意的排列顺序。

/etc/resolv.conf的一个示例：
domain centoscn.com
search  www.centocn.com www.wgjlb.com
nameserver 202.96.128.86
nameserver 202.96.128.166

最主要是nameserver关键字，如果没指定nameserver就找不到DNS服务器，其它关键字是可选的。Red Hat中没有提供缺省的/etc/resolv.conf文件，它的内容是根据在安装时给出的选项动态创建的。

redhat主机地址：192.168.2.60 。本地域名:localdomain，因为安装了bind-chroot，修改配置文件就在/var/named/chroot/etc/named.conf,/etc/named.conf则无效(bind运行后chroot的etc里面的name.rfc1912.zones好像会更新到/etc里面的name.rfc1912.zones)。

（In the zone definitions we defined the file containing the zone configuration. These files are located in the "/var/named/" directory. If you are using the "chroot" version of BIND, the location of the following files will be "/var/named/chroot/var/named" and you may need to change their group ownership to "named".）

此文件可以从该目录下named.caching-nameserver.conf复制而来。

配置信息如下：

options {
        listen-on port 53 { any; };            //所有机器都可以使用该dns服务器查询
        listen-on-v6 port 53 { ::1; };         //ip v6格式的写法，同上一个意思
        directory       "/var/named";
        dump-file       "/var/named/data/cache_dump.db";
        statistics-file "/var/named/data/named_stats.txt";
        memstatistics-file "/var/named/data/named_mem_stats.txt";
//      query-source    port 53;
//      query-source-v6 port 53;

        allow-query     { any; };
        allow-query-cache     { any; };
};
logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};
view localhost_resolver {
        match-clients      { any; };
        match-destinations { any; };
        recursion yes;
        include "/etc/named.rfc1912.zones";
};

然后配置正向ZONE和反向ZONE，配置文件为/var/named/chroot/etc/named.rfc1912.zones。因为现在我们的本地域名设置为localdomain，默认情况下zone文件里面在第15到第20行已经包含了localdomain域名的正向解析配置了，所以不用添加。如果本地域名适用其他域名如xxx.com之类，就需要参照localdomain的配置来修改即可。

 15 zone "localdomain" IN {
 16         type master;
 17         file "localdomain.zone";
 18         allow-update { none; };
 19 };

或者：

zone "xxx.com" IN {
        type master;
        file "xxx.com.zone";
        allow-update { none; };
};

反向配置则根据内网网段来配置，本地网段：192.168.2.0/24，另外一个网段为：10.10.10.0/24所以配置为：

zone "2.168.192.in-addr.arpa" IN {
        type master;
        file "2.168.192.in-addr.arpa";
        allow-update { none; };
};

zone "10.10.10.in-addr.arpa" IN {
        type master;
        file "10.10.10.in-addr.arpa";
        allow-update { none; };
};

接着，配置正反向解析数据库文件。利用/var/named/chroot/var/named/localhost.zone 复制生成正向解析的数据库文件，利用/var/named/chroot/var/named/localhost.zone 复制生成名为2.168.192.in-addr.arpa 的反向解析的数据库文件，记得带-p参数传递权限。

[root@linux named]# cp -p localhost.zone ./localdomain.zone
[root@linux named]# cp -p localhost.zone ./2.168.192.in-addr.arpa

再编辑解析数据库文件，使用不带域名后缀的short name即可。具体RAC环境的网络规划为：

Host name	Short  hostname	IP type	IP address	Interface
snode1.localdomain	snode1	Public ip	192.168.2.21	eth0
snode1-vip.localdomain	snode1-vip	Virtual ip	192.168.2.22	eth0:1
snode1-priv.localdomain	snode1-priv	Private ip	10.10.10.21	eth1
snode2.localdomain	snode2	Public ip	192.168.2.24	eth0
snode2-vip.localdomain	snode2-vip	Virtual ip	192.168.2.25	eth0:1
snode2-priv.localdomain	snode2-priv	Private ip	10.10.10.22	eth1
pnode1.localdomain	pnode1	Public ip	192.168.2.11	eth0
pnode1-vip.localdomain	pnode1-vip	Virtual ip	192.168.2.12	eth0:1
pnode1-priv.localdomain	pnode1-priv	Private ip	10.10.10.11	eth1
pnode2.localdomain	pnode2	Public ip	192.168.2.14	eth0
pnode2-vip.localdomain	pnode2-vip	Virtual ip	192.168.2.15	eth0:1
pnode2-priv.localdomain	pnode2-priv	Private ip	10.10.10.12	eth1
scan-cluster.localdomain	scan-cluster	Scan ip	192.168.2.23	eth0
scan-cluster.localdomain	scan-cluster	Scan ip	192.168.2.26	eth0
scan-cluster.localdomain	scan-cluster	Scan ip	192.168.2.13	eth0

配置完成的解析数据库文件为：

[root@linux named]# vim localdomain.zone 

$TTL    86400
@               IN SOA  localhost root (
                                        42              ; serial (d. adams)
                                        3H              ; refresh
                                        15M             ; retry
                                        1W              ; expiry
                                        1D )            ; minimum
                IN NS           localhost
localhost       IN A            127.0.0.1
pnode1          IN A            192.168.2.11
pnode1-vip      IN A            192.168.2.12
pnode1-priv     IN A            10.10.10.11
pnode2          IN A            192.168.2.14
pnode2-vip      IN A            192.168.2.15
pnode2-priv     IN A            10.10.10.12
snode1          IN A            192.168.2.21
snode1-vip      IN A            192.168.2.22
snode1-priv     IN A            10.10.10.21
snode2          IN A            192.168.2.24
snode2-vip      IN A            192.168.2.25
snode2-priv     IN A            10.10.10.22
scan-cluster    IN A            192.168.2.13
scan-cluster    IN A            192.168.2.23
scan-cluster    IN A            192.168.2.26

[root@linux named]# vim 2.168.192.in-addr.arpa

$TTL    86400
@       IN      SOA     localhost. root.localhost.  (
                                      1997022700 ; Serial
                                      28800      ; Refresh
                                      14400      ; Retry
                                      3600000    ; Expire
                                      86400 )    ; Minimum
        IN      NS      localhost.
60      IN      PTR     localhost.
11      IN      PTR     pnode1.localdomain
12      IN      PTR     pnode1-vip.localdomain
14      IN      PTR     pnode2.localdomain
15      IN      PTR     pnode2-vip.localdomain
21      IN      PTR     snode1.localdomain
22      IN      PTR     snode1-vip.localdomain
24      IN      PTR     snode2.localdomain
25      IN      PTR     snode2-vip.localdomain
23      IN      PTR     scan-cluster.localdomain
26      IN      PTR     scan-cluster.localdomain
13      IN      PTR     scan-cluster.localdomain

重启bind：/etc/init.d/named restart

验证解析结果，正向:

[root@linux named]# nslookup snode1
up scan-cluster
nslookup scan-clusterServer:        192.168.2.60
Address:    192.168.2.60#53

Name:    snode1.localdomain
Address: 192.168.2.21

[root@linux named]# nslookup snode1-vip
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    snode1-vip.localdomain
Address: 192.168.2.22

[root@linux named]# nslookup snode1-priv
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    snode1-priv.localdomain
Address: 10.10.10.21

[root@linux named]# nslookup snode2
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    snode2.localdomain
Address: 192.168.2.24

[root@linux named]# nslookup snode2-vip
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    snode2-vip.localdomain
Address: 192.168.2.25

[root@linux named]# nslookup snode2-priv
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    snode2-priv.localdomain
Address: 10.10.10.22

[root@linux named]# nslookup pnode1
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    pnode1.localdomain
Address: 192.168.2.11

[root@linux named]# nslookup pnode1-vip
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    pnode1-vip.localdomain
Address: 192.168.2.12

[root@linux named]# nslookup pnode1-priv
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    pnode1-priv.localdomain
Address: 10.10.10.11

[root@linux named]# nslookup pnode2
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    pnode2.localdomain
Address: 192.168.2.14

[root@linux named]# nslookup pnode2-vip
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    pnode2-vip.localdomain
Address: 192.168.2.15

[root@linux named]# nslookup pnode2-priv
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    pnode2-priv.localdomain
Address: 10.10.10.12

[root@linux named]# nslookup scan-cluster
Server:        192.168.2.60
Address:    192.168.2.60#53

Name:    scan-cluster.localdomain
Address: 192.168.2.13
Name:    scan-cluster.localdomain
Address: 192.168.2.23
Name:    scan-cluster.localdomain
Address: 192.168.2.26

反向：

[root@linux etc]# nslookup 192.168.2.21
Server:        192.168.2.60
Address:    192.168.2.60#53

21.2.168.192.in-addr.arpa    name = snode1.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.22
Server:        192.168.2.60
Address:    192.168.2.60#53

22.2.168.192.in-addr.arpa    name = snode1-vip.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 10.10.10.21
Server:        192.168.2.60
Address:    192.168.2.60#53

21.10.10.10.in-addr.arpa    name = snode1-priv.localdomain.10.10.10.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.24
Server:        192.168.2.60
Address:    192.168.2.60#53

24.2.168.192.in-addr.arpa    name = snode2.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.25
Server:        192.168.2.60
Address:    192.168.2.60#53

25.2.168.192.in-addr.arpa    name = snode2-vip.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 10.10.10.22
Server:        192.168.2.60
Address:    192.168.2.60#53

22.10.10.10.in-addr.arpa    name = snode2-priv.localdomain.10.10.10.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.11
Server:        192.168.2.60
Address:    192.168.2.60#53

11.2.168.192.in-addr.arpa    name = pnode1.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.12
Server:        192.168.2.60
Address:    192.168.2.60#53

12.2.168.192.in-addr.arpa    name = pnode1-vip.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 10.10.10.11
Server:        192.168.2.60
Address:    192.168.2.60#53

11.10.10.10.in-addr.arpa    name = pnode1-priv.localdomain.10.10.10.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.14
Server:        192.168.2.60
Address:    192.168.2.60#53

14.2.168.192.in-addr.arpa    name = pnode2.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.15
Server:        192.168.2.60
Address:    192.168.2.60#53

15.2.168.192.in-addr.arpa    name = pnode2-vip.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 10.10.10.12
Server:        192.168.2.60
Address:    192.168.2.60#53

12.10.10.10.in-addr.arpa    name = pnode2-priv.localdomain.10.10.10.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.23
Server:        192.168.2.60
Address:    192.168.2.60#53

23.2.168.192.in-addr.arpa    name = scan-cluster.localdomain.2.168.192.in-addr.arpa.

[root@linux etc]# nslookup 192.168.2.26
Server:        192.168.2.60
Address:    192.168.2.60#53

26.2.168.192.in-addr.arpa    name = scan-cluster.localdomain.2.168.192.in-addr.arpa.

说明配置成功。剩下的工作就是配置网络内其他主机的默认dns服务器地址就可以使用了。

但是在配置其他主机的DNS的服务器时我们通常使用/etc/resolv.conf文件来修改，但是我测试在centos7中修改后/etc/init.d/network restart重启网络，发现/etc/resolv.conf文件又被复原了，但是不重启网络又不能使DNS设置生效。如果是这样，解决方法就是修改网络接口的DNS配置，即/etc/sysconfig/network-script/ifcfg-ethN中增加dns的选项。参考https://blog.csdn.net/kadwf123/article/details/78786947。

具体步骤关闭NetworkManager是关键，方法如下：

[root@localhost etc]# service NetworkManager stop
Redirecting to /bin/systemctl stop  NetworkManager.service

[root@localhost etc]# /bin/systemctl stop  NetworkManager.service
[root@localhost etc]# service NetworkManager status
Redirecting to /bin/systemctl status  NetworkManager.service
● NetworkManager.service - Network Manager
   Loaded: loaded (/usr/lib/systemd/system/NetworkManager.service; disabled; vendor preset: enabled)
   Active: inactive (dead) since Wed 2019-05-08 23:29:19 CST; 29s ago
  Process: 10904 ExecStart=/usr/sbin/NetworkManager --no-daemon (code=exited, status=0/SUCCESS)
Main PID: 10904 (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/NetworkManager.service
           └─12251 /sbin/dhclient -d -q -sf /usr/libexec/nm-dhcp-helper -pf /...

[root@localhost etc]# chkconfig NetworkManager off
Note: Forwarding request to 'systemctl disable NetworkManager.service'.
[root@localhost etc]# systemctl disable NetworkManager.service