Version: Oracle Linux 6.6
With the help of volunteers in linuxquestions.org, I managed set up DNS for forward and reverse lookups. Special THANKS to Bathory
The domain I am trying to configure : openhex.com
DNS Server IP : 10.194.135.185
This is for Oracle RAC cluster build.
I want the hostname
rac-scan.openhex.com to resolve to the following 3 IPs .
10.194.135.82
10.194.135.83
10.194.135.84
This is for the SCAN functionality in Oracle RAC
One of the requirements in resolving is that ;
it should resolve in a round-robin fashion. . I managed to acheive it but I don't know how.
Demo:
As you can see below,
the 1st time I did the nslookup, it resolved to 10.194.135.84
the 2nd time I did the nslookup, it resolved to 10.194.135.82
the 3rd time, I did the nslookup, it resolved to 10.194.135.83
This round-robin cycle continues in the same sequence
[root@pravda178 ~]# nslookup rac-scan.openhex.com
Server: 10.194.135.185
Address: 10.194.135.185#53
Name: rac-scan.openhex.com
Address: 10.194.135.84
Name: rac-scan.openhex.com
Address: 10.194.135.82
Name: rac-scan.openhex.com
Address: 10.194.135.83
[root@pravda178 ~]#
[root@pravda178 ~]#
[root@pravda178 ~]# nslookup rac-scan.openhex.com
Server: 10.194.135.185
Address: 10.194.135.185#53
Name: rac-scan.openhex.com
Address: 10.194.135.82
Name: rac-scan.openhex.com
Address: 10.194.135.83
Name: rac-scan.openhex.com
Address: 10.194.135.84
[root@pravda178 ~]#
[root@pravda178 ~]# nslookup rac-scan.openhex.com
Server: 10.194.135.185
Address: 10.194.135.185#53
Name: rac-scan.openhex.com
Address: 10.194.135.83
Name: rac-scan.openhex.com
Address: 10.194.135.84
Name: rac-scan.openhex.com
Address: 10.194.135.82
How is the above mentioned round-robin acheived ? Is it some configuration in /etc/named.conf file or the forward zone file /var/named/openhex.com.zone ?
--- Following are the 2 configuration files I've used.
#### 1. /etc/named.conf
[root@oem12cdns185 etc]# cat /etc/named.conf
options {
listen-on port 53 {127.0.0.1; 10.194.135.185; };
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";
allow-recursion { localnets; localhost;};
dnssec-enable yes;
dnssec-validation yes;
dnssec-lookaside auto;
/* Path to ISC DLV key */
bindkeys-file "/etc/named.iscdlv.key";
managed-keys-directory "/var/named/dynamic";
};
zone "openhex.com" IN {
type master;
file "openhex.com.zone";
allow-update { none; };
};
zone "135.194.10.in-addr.arpa." IN {
type master;
file "135.194.10.in-addr.arpa";
allow-update { none; };
};
include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";
### 2. forward zone file
### /var/named/openhex.com.zone
[root@oem12cdns185 etc]#
[root@oem12cdns185 etc]# cat /var/named/openhex.com.zone
$TTL 86400
@ IN SOA localhost root.localhost (
42 ; serial (d. adams)
3H ; refresh
15M ; retry
1W ; expiry
1D ) ; minimum
IN NS openhex.com.
;localhost IN A 127.0.0.1 ;;No needed
openhex.com. A 10.194.135.185
pravda178-oravip.openhex.com. IN A 10.194.135.217
pravda179-oravip.openhex.com. IN A 10.194.135.218
rac-scan.openhex.com. IN A 10.194.135.82
rac-scan.openhex.com. IN A 10.194.135.83
rac-scan.openhex.com. IN A 10.194.135.84
