在搭建RAC时，scanip需要dns解析，下面演示如何配置dns
服务器环境：rhel-server-7.3-x86_64
域名解析：ol7-122-scan.fly.cn
3个scanip： 192.168.56.105
192.168.56.106
192.168.56.107
1、安装bind包
[root@ol7-122-rac1 ~]# yum list|grep bind-chroot
bind-chroot.x86_64 32:9.9.4-37.el7 rhel-media
[root@ol7-122-rac1 ~]# yum -y install bind-chroot.x86_64
修改/etc/named.conf 文件如下：
[root@ol7-122-rac1 named]# more /etc/named.conf
//
// named.caching-nameserver.conf
//
// Provided by Red Hat caching-nameserverpackage to configure the
// ISC BIND named(8) DNS server as acaching only nameserver
// (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ forexample named configuration files.
//
// DO NOT EDIT THIS FILE - usesystem-config-bind or an editor
// to create named.conf - edits to thisfile will be lost on
// caching-nameserver package upgrade.
//
options {
listen-on port 53 { any; };
listen-on-v6 port 53 { ::1; };
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";
// Those options should be used carefully because they disable port
// randomization
// 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";
};
2、修改/etc/named.rfc1912.zones文件
增加以下的正向解析和反向解析信息
[root@ol7-122-rac1 named]# vi /etc/named.rfc1912.zones
zone "fly.cn" IN {
type master;
file "fly.cn.zone";
allow-update { none; };
};
zone "56.168.192.in-addr.arpa" IN{
type master;
file "56.168.192.local";
allow-update { none; };
};
3、新增正向解析文件
(如配置不当会报错 zonefly.cn/IN: NS 'dns.fly.cn' has no address records (A or AAAA)，参考附1； 此处演示正常文件)：
[root@ol7-122-rac1 named]# vi /var/named/fly.cn.zone
$TTL 86400
@ IN SOA dns.fly.cn. root.fly.cn. (
42 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D) ; minimum
IN NS dns.fly.cn.
ol7-122-scan IN A 192.168.56.105
ol7-122-scan IN A 192.168.56.106
ol7-122-scan IN A 192.168.56.107
dns.fly.cn. IN A 192.168.56.101
dns.fly.cn. IN A 192.168.56.102
4、添加反向解析文件：
[root@ol7-122-rac1 named]# vi /var/named/56.168.192.local
$TTL 86400
@ IN SOA dns.fly.cn. root.fly.cn. (
1997022700 ; Serial
28800 ; Refresh
14400 ; Retry
3600000 ; Expire
86400) ; Minimum
IN NS dns.fly.cn.
105 IN PTR ol7-122-scan.fly.cn.
106 IN PTR ol7-122-scan.fly.cn.
107 IN PTR ol7-122-scan.fly.cn.
5、配置/etc/resolv.conf文件，
解析dns
[root@ol7-122-rac1 named]# vi /etc/resolv.conf
# Generated by NetworkManager
search localdomain
nameserver 192.168.56.101
重启dns
[root@ol7-122-rac1 named]# systemctl restart named
6、检测dns是否好用
[root@ol7-122-rac1 named]# nslookup ol7-122-scan.fly.cn
Server: 192.168.56.101
Address: 192.168.56.101#53
Name: ol7-122-scan.fly.cn
Address: 192.168.56.105
Name: ol7-122-scan.fly.cn
Address: 192.168.56.106
Name: ol7-122-scan.fly.cn
Address: 192.168.56.107
附1：zone fly.cn/IN: NS 'dns.fly.cn' has no address records (A or AAAA) 问题
问题：
初始配置正向解析文件时如下：
[root@ol7-122-rac1 named]# vi/var/named/fly.cn.zone
$TTL 86400
@ IN SOA dns.fly.cn. root.fly.cn. (
42 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D) ; minimum
IN NS dns.fly.cn.
ol7-122-scan IN A 192.168.56.105
ol7-122-scan IN A 192.168.56.106
ol7-122-scan IN A 192.168.56.107
重启dns时报错
[root@ol7-122-rac1 named]# systemctlrestart named
Starting named:
Error in named configuration:
zone localhost.localdomain/IN: loadedserial 0
zone localhost/IN: loaded serial 0
zone1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa/IN:loaded serial 0
zone 1.0.0.127.in-addr.arpa/IN: loadedserial 0
zone 0.in-addr.arpa/IN: loaded serial 0
zone fly.cn/IN: NS 'dns.fly.cn' has noaddress records (A or AAAA)
zone fly.cn/IN: not loaded due to errors.
localhost_resolver/fly.cn/IN: bad zone
zone 56.168.192.in-addr.arpa/IN: loadedserial 1997022700
[FAILED]
解决方案：
在正向解析文件添加如下信息：
[root@ol7-122-rac1 named]# vi/var/named/fly.cn.zone
dns.fly.cn. IN A 192.168.56.101
dns.fly.cn. IN A 192.168.56.102
再次重启dns时无问题
[root@ol7-122-rac1 named]# systemctlrestart named