Network Practices - Expert Oracle RAC 12c - page 269

The steps for implementing GNS name resolution using this example are as follows:
Step 1: On the DNS server, add a zone dblab.com to /etc/named.conf file. This zone handles DNS queries for the
domain's subnet, “ dblab.com ” :
zone " dblab.com " {
type master;
file " dblab.com.zone ";
};
Then, add these entries to the zone file /var/named/dblab.com.zone to specify the VIP of GNS server
gns.kcloud.dblab.com : 172.16.150.9 and the subdomain kcloud.dblab.com delegation to forward to GNS server
gns.kcloud.dblab.com .
# cat /var/named/dblab.com.zone
。。。。。。
$ORIGIN kcloud.dblab.com .
@ IN NS gns.kcloud.dblab.com .
gns.kcloud.dblab.com . IN A 172.16.150.9
Step 2: On all DNS clients (all the nodes in the cluster), add these entries to /etc/resolve.conf file:
# cat /etc/resolv.conf
options attempts: 2
Options timeout: 1
nameserver 172.16.15.9
nameserver 172.16.168.8
search kcloud.dblab.com dblab.com
Here, 172.16.168.8 is the IP of the DNS server and 172.16.15.9 is the GNS server VIP of the cluster.
Step 3: Enable the “Configure GNS” option in Grid Infrastructure installation and specify the GNS configuration,
including GNS subdomain and GNS VIP address. The Grid Infrastructure installation will create and configure GNS
service. This will be discussed in the next session.
Network Specification in Grid Infrastructure Installation
With all the configurations and preparation work done, you can complete the network configuration through Oracle
Grid Infrastructure installation. During the installation, the network configuration information, such as the public
hostname and virtual hostname of each node in the cluster, the SCAN name, and the network interfaces for the public
and private networks, have to be specified.
Select Whether or Not to Use GNS
If you decide to use GNS for the name resolution, you need to check the box next to “Configure GNS” on the Grid Plug
and Play information page. In Oracle 12c, a single GNS can be shared by multiple clusters. When you create a new
cluster, you can either share an existing GNS with other cluster by selecting “Use Shared GNS” or create a new GNS by
selecting the “Create a New GNS” option. On the same page, you also need to fill out the GNS subdomain and the GNS
VIP address as shown in Figure 9-11 , which uses the knewrac cluster as an example.