RAC的dns server配置

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RAC的dns server配置

2014年01月22日 ⁄ 综合 ⁄ 共 12537字 ⁄ 字号小中大 ⁄ 评论关闭

在oracle 11gR2 RAC中，oracle使用了SCAN（single client access name），在VIP的上面又加了一层网络管理，虽说方便了客户端，在RAC增加节点数量的时候，在客户端的tnsnames不进行改动，对于一个数据库服务多个应用服务器的场景提供了方便，但是，由于oracle把手伸到了网络层面，多一层SCAN IP也多一层故障的可能性。

在安装11gR2 RAC的时候，由于oracle强制使用SCAN，在安装时如果没有启用DNS，安装就会进行不下去。报错INS-40922和INS-40718。虽然我们可以使用单个IP做SCAN，但是oracle还是比较推荐使用DNS服务，或者采用GNS服务。

在这里我们来为RAC配置一个DNS server。
相关的IP是如下设置的：

127.0.0.1 localhost.localdomain localhost
#DNS server
192.168.190.220 dnsserver.oracleblog.org dnsserver
# Public
192.168.190.101 rac1.oracleblog.org rac1
192.168.190.102 rac2.oracleblog.org rac2
# Private
192.168.0.101 rac1-priv.oracleblog.org rac1-priv
192.168.0.102 rac2-priv.oracleblog.org rac2-priv
# Virtual
192.168.190.111 rac1-vip.oracleblog.org rac1-vip
192.168.190.112 rac2-vip.oracleblog.org rac2-vip
# SCAN
192.168.190.201 rac-scan.oracleblog.org rac-scan
192.168.190.202 rac-scan.oracleblog.org rac-scan
192.168.190.203 rac-scan.oracleblog.org rac-scan

首先，我们到DNS服务器上配置DNS服务，
我们进入/var/named/chroot/etc，看看是否存在相关的配置文件：

[root@dnsserver etc]#cd /var/named/chroot
[root@dnsserver etc]# ll
total 16
-rw-r--r-- 1 root root 3519 Feb 27 2006 localtime
-rw-r----- 1 root named 113 May 23 00:45 rndc.key

此时相关的配置文件都还不存在，如果我们启动DNS服务，就会报错fail：

[root@dnsserver etc]# service named start
Locating /var/named/chroot//etc/named.conf failed:
[FAILED]
[root@dnsserver etc]#

好，下面我们开始配置，我们touch一个named.conf，然后在里面输入：

[root@dnsserver etc]# cat named.conf
//

// named.conf for Red Hat caching-nameserver

//

options {

   directory "/var/named";

   dump-file "/var/named/data/cache_dump.db";

   statistics-file "/var/named/data/named_stats.txt";

   /*

   * If there is a firewall between you and nameservers you want

   * to talk to, you might need to uncomment the query-source

   * directive below. Previous versions of BIND always asked

   * questions using port 53, but BIND 8.1 uses an unprivileged

   * port by default.

   */

   // query-source address * port 53;

};

//

// a caching only nameserver config

//

controls {

   inet 127.0.0.1 allow { localhost; } keys { rndckey; };

};

zone "." IN {

   type hint;

   file "named.ca";

};

zone "localdomain" IN {

   type master;

   file "localdomain.zone";

   allow-update { none; };

};

zone "localhost" IN {

   type master;

   file "localhost.zone";

   allow-update { none; };

};

zone "0.0.127.in-addr.arpa" IN {

   type master;

   file "named.local";

   allow-update { none; };

};

######################################
# ADD for oracle RAC SCAN,
# START FROM HERE
######################################
zone "190.168.192.in-addr.arpa" IN {

   type master;

   file "190.168.192.in-addr.local";

   allow-update { none; };

};

zone "oracleblog.org" IN {

   type master;

   file "oracleblog.org.zone";

   allow-update { none; };

};
######################################
# ADD for oracle RAC SCAN,
# END FROM HERE
######################################

我们看到，上面有6个zone，其中前面4个zone是系统的，后面的2个zone是我们给RAC的SCAN配置的。对应的每个zone，我们都有一个对应的file放在/var/named/chroot/var/named下。

zone .=>named.ca
zone localdomain=>localdomain.zone
zone localhost=>localhost.zone
zone 0.0.127.in-addr.arpa=>named.local
zone 190.168.192.in-addr.arpa=>190.168.192.in-addr.local
zone oracleblog.org=>oracleblog.org.zone

如果在/var/named/chroot/var/named下你找不到相关的zone文件，也没关系，在/usr/share/doc/bind-9.3.6/sample/var/named下就有相关的sample文件（Oracle Linux Enterprise 5 update 8），我们拷贝过来就可以用。

拷贝过来后，在/var/named/chroot/var/named有：

[root@dnsserver named]# ls -l
total 60
drwxrwx--- 2 named named 4096 Aug 26 2004 data
-rw-r--r-- 1 root root 198 Dec 20 17:01 localdomain.zone
-rw-r--r-- 1 root root 195 Dec 20 17:01 localhost.zone
-rw-r--r-- 1 root root 56 Dec 20 17:18 my.external.zone.db
-rw-r--r-- 1 root root 56 Dec 20 17:18 my.internal.zone.db
-rw-r--r-- 1 root root 427 Dec 20 17:01 named.broadcast
-rw-r--r-- 1 root root 424 Dec 20 17:01 named.ip6.local
-rw-r--r-- 1 root root 426 Dec 20 17:01 named.local
-rw-r--r-- 1 root root 1892 Dec 20 17:01 named.root
-rw-r--r-- 1 root root 427 Dec 20 17:01 named.zero
drwxrwx--- 2 named named 4096 Jul 27 2004 slaves
[root@dnsserver named]#

此时，你会发现，190.168.192.in-addr.local和oracleblog.org.zone还有named.ca还没有呢？别急，前2个文件我们可以从named.local和localdomain.zone借鉴，而named.ca是个固定的文件，记录着根服务器的地址，一般情况下不会改变，我们可以在网上抄一个。

[root@dnsserver named]# cp -p named.local 190.168.192.in-addr.local
[root@dnsserver named]# cp -p localdomain.zone oracleblog.org.zone
[root@dnsserver named]# ls -lrt
total 68
drwxrwx--- 2 named named 4096 Jul 27 2004 slaves
drwxrwx--- 2 named named 4096 Aug 26 2004 data
-rw-r--r-- 1 root root 427 Dec 20 17:01 named.zero
-rw-r--r-- 1 root root 1892 Dec 20 17:01 named.root
-rw-r--r-- 1 root root 426 Dec 20 17:01 named.local
-rw-r--r-- 1 root root 424 Dec 20 17:01 named.ip6.local
-rw-r--r-- 1 root root 427 Dec 20 17:01 named.broadcast
-rw-r--r-- 1 root root 195 Dec 20 17:01 localhost.zone
-rw-r--r-- 1 root root 198 Dec 20 17:01 localdomain.zone
-rw-r--r-- 1 root root 56 Dec 20 17:18 my.internal.zone.db
-rw-r--r-- 1 root root 56 Dec 20 17:18 my.external.zone.db
-rw-r--r-- 1 root root 761 May 23 18:19 oracleblog.org.zone
-rw-r--r-- 1 root root 559 May 23 18:20 190.168.192.in-addr.local
[root@dnsserver named]#

ok，借鉴归借鉴，里面文件中的内容我们还是要修改的，修改完成后，内容如下：

[root@dnsserver named]# cat 190.168.192.in-addr.local
$TTL 86400
@ IN SOA localhost. root.localhost. (
   1997022700 ; Serial
   28800 ; Refresh
   14400 ; Retry
   3600000 ; Expire
   86400 ) ; Minimum
   IN NS oracleblog.org.
101 IN PTR rac1.oracleblog.org.
102 IN PTR rac2.oracleblog.org.
201 IN PTR rac-scan.oracleblog.org.
202 IN PTR rac-scan.oracleblog.org.
203 IN PTR rac-scan.oracleblog.org.

[root@dnsserver named]# cat oracleblog.org.zone
$TTL 86400
@ IN SOA localhost root(
   42 ; serial (d. adams)
   3H ; refresh
   15M ; retry
   1W ; expiry
   1D ) ; minimum
   IN NS oracleblog.org.
rac1 IN A 192.168.190.101
rac2 IN A 192.168.190.102
rac-scan IN A 192.168.190.201
rac-scan IN A 192.168.190.202
rac-scan IN A 192.168.190.203
rac1-vip IN A 192.168.190.111
rac2-vip IN A 192.168.190.112

named.ca文件的内容：

; This file holds the information on root name servers needed to
; initialize cache of Internet domain name servers
; (e.g. reference this file in the "cache . <file>;"
; configuration file of BIND domain name servers).
;
; This file is made available by InterNIC registration services
; under anonymous FTP as
; file /domain/named.root
; on server FTP.RS.INTERNIC.NET
; -OR- under Gopher at RS.INTERNIC.NET
; under menu InterNIC Registration Services (NSI)
; submenu InterNIC Registration Archives
; file named.root
;
; last update: Aug 22, 1997
; related version of root zone: 1997082200
; $FreeBSD: src/etc/namedb/named.root,v 1.9 1999/09/13 17:09:08 peter Exp $
;
; formerly NS.INTERNIC.NET
;
. 3600000 IN NS A.ROOT-SERVERS.NET.
A.ROOT-SERVERS.NET. 3600000 A 198.41.0.4
;
; formerly NS1.ISI.EDU
;
. 3600000 NS B.ROOT-SERVERS.NET.
B.ROOT-SERVERS.NET. 3600000 A 128.9.0.107
;
; formerly C.PSI.NET
;
. 3600000 NS C.ROOT-SERVERS.NET.
C.ROOT-SERVERS.NET. 3600000 A 192.33.4.12
;
; formerly TERP.UMD.EDU
;
. 3600000 NS D.ROOT-SERVERS.NET.
D.ROOT-SERVERS.NET. 3600000 A 128.8.10.90
;
; formerly NS.NASA.GOV
;
. 3600000 NS E.ROOT-SERVERS.NET.
E.ROOT-SERVERS.NET. 3600000 A 192.203.230.10
;
; formerly NS.ISC.ORG
;
. 3600000 NS F.ROOT-SERVERS.NET.
F.ROOT-SERVERS.NET. 3600000 A 192.5.5.241
;
; formerly NS.NIC.DDN.MIL
;
. 3600000 NS G.ROOT-SERVERS.NET.
G.ROOT-SERVERS.NET. 3600000 A 192.112.36.4
;
; formerly AOS.ARL.ARMY.MIL
;
. 3600000 NS H.ROOT-SERVERS.NET.
H.ROOT-SERVERS.NET. 3600000 A 128.63.2.53
;
; formerly NIC.NORDU.NET
;
. 3600000 NS I.ROOT-SERVERS.NET.
I.ROOT-SERVERS.NET. 3600000 A 192.36.148.17
;
; temporarily housed at NSI (InterNIC)
;
. 3600000 NS J.ROOT-SERVERS.NET.
J.ROOT-SERVERS.NET. 3600000 A 198.41.0.10
;
; housed in LINX, operated by RIPE NCC
;
. 3600000 NS K.ROOT-SERVERS.NET.
K.ROOT-SERVERS.NET. 3600000 A 193.0.14.129
;
; temporarily housed at ISI (IANA)
;
. 3600000 NS L.ROOT-SERVERS.NET.
L.ROOT-SERVERS.NET. 3600000 A 198.32.64.12
;
; housed in Japan, operated by WIDE
;
. 3600000 NS M.ROOT-SERVERS.NET.
M.ROOT-SERVERS.NET. 3600000 A 202.12.27.33
; End of File

此时，大部分的DNS服务器基本已经配置完成，不过你还需要建一个soft link和授权777。在这里提前说一句，如果你的DNS服务起不来，启动时候就一个报错fail，你可以用named -d 3 -f -g这个命令来诊断。
（1）创建soft link：

[root@dnsserver etc]# ln -s /var/named/chroot/etc/named.conf /etc/named.conf

如果不建立该soft link，会报错以下错误。

[root@dnsserver named]# named -d 3 -f -g
23-May-2012 17:56:36.860 starting BIND 9.3.6-P1-RedHat-9.3.6-20.P1.el5 -d 3 -f -g
23-May-2012 17:56:36.860 adjusted limit on open files from 1024 to 1048576
23-May-2012 17:56:36.860 found 1 CPU, using 1 worker thread
23-May-2012 17:56:36.861 using up to 4096 sockets
23-May-2012 17:56:36.866 loading configuration from '/etc/named.conf'
23-May-2012 17:56:36.866 none:0: open: /etc/named.conf: file not found
23-May-2012 17:56:36.874 load_configuration: file not found
23-May-2012 17:56:36.874 loading configuration: file not found
23-May-2012 17:56:36.874 exiting (due to fatal error)
[root@dnsserver named]#

（2）赋权777：

[root@dnsserver run]# cd /var/run
[root@dnsserver run]# chmod 777 named

如果不赋权，会报错以下错误。

[root@dnsserver named]# named -d 3 -f -g
23-May-2012 18:08:32.901 starting BIND 9.3.6-P1-RedHat-9.3.6-20.P1.el5 -d 3 -f -g
23-May-2012 18:08:32.901 adjusted limit on open files from 1024 to 1048576
23-May-2012 18:08:32.901 found 1 CPU, using 1 worker thread
23-May-2012 18:08:32.902 using up to 4096 sockets
23-May-2012 18:08:32.908 loading configuration from '/etc/named.conf'
23-May-2012 18:08:32.909 set maximum stack size to 4294967295: success
23-May-2012 18:08:32.909 set maximum data size to 4294967295: success
23-May-2012 18:08:32.910 set maximum core size to 4294967295: success
23-May-2012 18:08:32.910 set maximum open files to -1: success
23-May-2012 18:08:32.910 using default UDP/IPv4 port range: [1024, 65535]
23-May-2012 18:08:32.911 using default UDP/IPv6 port range: [1024, 65535]
23-May-2012 18:08:32.938 no IPv6 interfaces found
23-May-2012 18:08:32.938 listening on IPv4 interface lo, 127.0.0.1#53
23-May-2012 18:08:32.938 clientmgr @0xb8b46f90: create
23-May-2012 18:08:32.939 clientmgr @0xb8b46f90: createclients
23-May-2012 18:08:32.939 clientmgr @0xb8b46f90: create new
23-May-2012 18:08:32.939 client @0xb8b67800: create
23-May-2012 18:08:32.939 clientmgr @0xb8b46f90: createclients
23-May-2012 18:08:32.939 clientmgr @0xb8b46f90: create new
23-May-2012 18:08:32.939 client @0xb8b69638: create
23-May-2012 18:08:32.939 listening on IPv4 interface eth0, 192.168.190.201#53
23-May-2012 18:08:32.939 clientmgr @0xb8b6b410: create
23-May-2012 18:08:32.939 clientmgr @0xb8b6b410: createclients
23-May-2012 18:08:32.940 clientmgr @0xb8b6b410: create new
23-May-2012 18:08:32.940 client @0xb8b6ba60: create
23-May-2012 18:08:32.940 clientmgr @0xb8b6b410: createclients
23-May-2012 18:08:32.940 clientmgr @0xb8b6b410: create new
23-May-2012 18:08:32.940 client @0xb8b6d908: create
23-May-2012 18:08:32.941 res 0xb8b77310: create
23-May-2012 18:08:32.941 dns_requestmgr_create
23-May-2012 18:08:32.941 dns_requestmgr_create: 0xb8b7ac50
23-May-2012 18:08:32.941 dns_requestmgr_whenshutdown
23-May-2012 18:08:32.942 res 0xb8b82808: create
23-May-2012 18:08:32.942 dns_requestmgr_create
23-May-2012 18:08:32.942 dns_requestmgr_create: 0xb8b83ed8
23-May-2012 18:08:32.942 dns_requestmgr_whenshutdown
23-May-2012 18:08:32.943 command channel listening on 127.0.0.1#953
23-May-2012 18:08:32.943 ignoring config file logging statement due to -g option
23-May-2012 18:08:32.943 couldn't open pid file '/var/run/named/named.pid': Permission denied
23-May-2012 18:08:32.943 exiting (due to early fatal error)
[root@dnsserver named]#

好了，在DNS服务器端，我们就配置完成了，启动DNS服务器，即可正常工作了。

[root@dnsserver var]# service named stop
Stopping named: [ OK ]
[root@dnsserver var]# service named start
Starting named: [ OK ]
[root@dnsserver var]#

设置完成DNS服务器，我们还需要在所有的数据库服务器端做一些设置：
在数据库服务器端，修改/etc/resolv.conf文件，设置DNS服务器，加上搜索域：

[root@rac2 ~]# cat /etc/resolv.conf
search oracleblog.org
nameserver 192.168.190.220
nameserver 192.168.190.1

建立/etc/host.conf文件，指定解析顺序，先DNS，再hosts

order bind,hosts
multi on

ok，我们在安装界面输入完成后，valid SCAN，点击next，就会进入到安装的下一步。

此时，你可以nslookup SCAN，就会发现通过DNS服务，对3个IP192.168.190.201、192.168.190.202、192.168.190.203进行轮询了：

[root@rac1 ~]# nslookup rac-scan
Server: 192.168.190.220
Address: 192.168.190.220#53

Name: rac-scan.oracleblog.org
Address: 192.168.190.202
Name: rac-scan.oracleblog.org
Address: 192.168.190.203
Name: rac-scan.oracleblog.org
Address: 192.168.190.201

[root@rac1 ~]# nslookup rac-scan
Server: 192.168.190.220
Address: 192.168.190.220#53

Name: rac-scan.oracleblog.org
Address: 192.168.190.201
Name: rac-scan.oracleblog.org
Address: 192.168.190.202
Name: rac-scan.oracleblog.org
Address: 192.168.190.203

[root@rac1 ~]# nslookup rac-scan
Server: 192.168.190.220
Address: 192.168.190.220#53

Name: rac-scan.oracleblog.org
Address: 192.168.190.203
Name: rac-scan.oracleblog.org
Address: 192.168.190.201
Name: rac-scan.oracleblog.org
Address: 192.168.190.202

[root@rac1 ~]#

原文地址：http://www.oracleblog.org/study-note/how-to-install-dns-server-for-rac/

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作者: cavern

该日志由 cavern 于10年前发表在综合分类下，最后更新于 2014年01月22日.
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RAC的dns server配置

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