The IP addresses associated with the SCAN VIP resources are initially set when the SCAN resources are created. Any changes to the DNS entry for the SCAN are not automatically propagated to the clusterware and need to be done manually. This applies only to installations that are not using GNS. The information in this note can also be helpful in cases where SCAN was originally configured with just one address and is now being expanded to accommodate three IP addresses.
Below is an example using the following configuration:
subnet of the public network is 10.100.10.0
netmask for the public network is 255.255.255.0
name of the public interface is eth1
old IP addresses: 10.100.10.81, 10.100.10.82 & 10.100.10.83
new IP addresses: 10.100.10.121, 10.100.10.122 & 10.100.10.123
Stopping & starting the SCAN VIPs/listeners can be done by the grid user, however, the ‘srvctl modify scan’ command must be executed by the root user, so it’s practical to execute all steps as the root user.
Modifying SCAN VIP resources
1. Before the SCAN VIPs can be changed, the entry for the SCAN name on the Domain Name Server (DNS) needs to be updated with the new IP addresses. This usually will be done by a network administrator. To check the current setting, the following command can be used:
# nslookup [scan_name]
A lookup of the SCAN on the DNS server shows that the entry has already been updated with the new IP addresses:
$ nslookup scan.example.com Server: dns1.example.com Address: 10.100.10.70#53 Name: scan.example.com Address: 10.100.10.123 Name: scan.example.com Address: 10.100.10.122 Name: scan.example.com Address: 10.100.10.121
2. To check the current IP address(es) of the SCAN VIPs, run the following commands as the root user:
# $GRID_HOME/bin/srvctl config scan
$GRID_HOME : home path for GRID software.
The SCAN VIP resources will still show the old IP addresses:
# $GRID_HOME/bin/srvctl config scan SCAN name: scan, Network: 1/10.100.10.0/255.255.255.0/eth1 SCAN VIP name: scan1, IP: /scan.example.com/10.100.10.81 SCAN VIP name: scan2, IP: /scan.example.com/10.100.10.82 SCAN VIP name: scan3, IP: /scan.example.com/10.100.10.83
3. Stop the SCAN listeners and SCAN as root user.
# GRID_HOME/bin/srvctl stop scan_listener # GRID_HOME/bin/srvctl stop scan
Verify if SCAN and SCAN listener has stopped.
# $GRID_HOME/bin/srvctl status scan SCAN VIP scan1 is enabled SCAN VIP scan1 is not running SCAN VIP scan2 is enabled SCAN VIP scan2 is not running SCAN VIP scan3 is enabled SCAN VIP scan3 is not running
# $GRID_HOME/bin/srvctl status scan_listener SCAN Listener LISTENER_SCAN1 is enabled SCAN listener LISTENER_SCAN1 is not running SCAN Listener LISTENER_SCAN2 is enabled SCAN listener LISTENER_SCAN2 is not running SCAN Listener LISTENER_SCAN3 is enabled SCAN listener LISTENER_SCAN3 is not running
4. Next refresh the SCAN VIPs with the new IP addresses from the DNS entry:
# $GRID_HOME/bin/srvctl modify scan -n [scan_name]
For example :
# $GRID_HOME/bin/srvctl modify scan -n scan.example.com
5. To check if the SCAN VIPs have been changed, run the following command, it should now show the new IP addresses.
# GRID_HOME/bin/srvctl config scan SCAN name: scan, Network: 1/10.100.10.0/255.255.255.0/eth1 SCAN VIP name: scan1, IP: /scan.example.com/10.100.10.121 SCAN VIP name: scan2, IP: /scan.example.com/10.100.10.122 SCAN VIP name: scan3, IP: /scan.example.com/10.100.10.123
6. Restart SCAN & SCAN listener:
# GRID_HOME/bin/srvctl start scan # GRID_HOME/bin/srvctl start scan_listener
7. If the number of SCAN VIPs has changed, the SCAN listener needs to be updated:
# GRID_HOME/bin/srvctl modify scan_listener -u