Changing the DNS Servers

You can change the configuration settings for the Domain Name System (DNS) servers after the initial setup. All servers and switches in Recovery Appliance must reference the same DNS servers. This section explains how to set the servers and switches to the same DNS servers. Oracle recommends changing the servers one at a time.

Changing the DNS Server Address on an InfiniBand Switch

To change the DNS server address on an InfiniBand switch, connect to Oracle ILOM and log in as the ilom-admin user. You can choose from one of the following methods:

Oracle ILOM web interface

Select the Configuration tab and set the DNS server addresses.
Oracle ILOM CLI

Use the following command to set the DNS:
```
set /SP/clients/dns nameserver=dns_ip
```
In the preceding command, dns_ip is the IP address of the DNS server. For multiple servers, enter a comma-separated list. For example:
```
set /SP/clients/dns nameserver=dns_ip1,dns_ip2,dns_ip3
```

Changing the DNS Server Address on the Cisco Ethernet Switch

To change the DNS server address on the Cisco Ethernet switch:

Access the Ethernet switch using SSH, and log in as the admin user with the administrator password.

If SSH is not configured, then use Telnet to access the switch.
Change to enable mode:
```
Switch> enable
```
List the DNS IP addresses currently in use:
```
Switch# show running-config
```

Erase the current DNS server addresses and any invalid IP addresses. This example erases three IP addresses:

Switch# configure terminal
Enter configuration commands,one per line. End with CNTL/Z.
Switch(config)# no ip name-server 10.7.7.2
Switch(config)# no ip name-server 129.148.5.4
Switch(config)# no ip name-server 10.8.160.2
Switch(config)# end
Switch# write memory
Building configuration...
Compressed configuration from 2603 bytes to 1158 bytes [OK ]

Configure up to three DNS servers. The following example configures three new DNS servers:

Switch# configure terminal
Enter configuration commands,one per line. End with CNTL/Z.
Switch(config)# ip name-server 10.7.7.3
Switch(config)# ip name-server 129.148.5.5
Switch(config)# ip name-server 10.8.160.1
Switch(config)# write memory 
Building configuration...
Compressed configuration from 2603 bytes to 1158 bytes [OK ]

Verify the changes:

Switch# show running-config
Building configuration...
...
ip domain-name example.com
ip name-server 192.168.10.2
ip name-server 192.168.10.3
ip name-server 192.168.10.4
...

Save the running configuration as the startup configuration:

Switch# copy running-config startup-config
Destination filename [startup-config]? 
Building configuration...
Compressed configuration from 14343 bytes to 3986 bytes[OK]

End the session:
```
Switch# exit
```

Changing the DNS Server Address on the Compute Server

To change the DNS server address on the compute servers:

Log in as the root user.
Open /etc/resolv.conf file in a text editor.
Locate the name server setting for the DNS server and change it to the new value. For example:
```
search        example.com
nameserver    10.7.7.3
```
Save the file and close the editor.
Set the DNS server in the server ILOM:
```
ipmitool sunoem cli 'set /SP/clients/dns nameserver=dns_ip'
```
In the preceding command, dns_ip is the IP address of the DNS server. For multiple DNS servers, enter a comma-separated list. For example:
```
set /SP/clients/dns nameserver=dns_ip1,dns_ip2,dns_ip3
```
Repeat this procedure for each compute server.

Changing the DNS Server on Storage Servers

To change the DNS server or NTP settings on a storage server:

Log in to the storage server as the root user.
Follow steps 1 through 5 of My Oracle Support Doc ID 1188080.1 to take the server offline.

Shut down the cell services and ocrvottargetd service:

# cellcli -e alter cell shutdown services all
# service ocrvottargetd stop

Use the ipconf utility to change the DNS settings:
```
# /usr/local/bin/ipconf
```
Restart the server:
```
# shutdown -r now
```
Follow steps 7 through 9 of My Oracle Support note 1188080.1 to put the server back online.
Repeat this procedure for each storage server.