How to recreate SCAN listeners to align nslookup IP adresses and SCAN listeners

Overview

- A SCAN  name which can resolve upto maximum three IP address 
- For each of these IP addresses a  SCAN VIP or SCAN IP is available 
- Each Scan VIP has a SCAN Listener generated corresponding to it. 
  If there are three SCAN VIP's three SCAN Listeners will be generated.
- For a SCAN name returning 3 addresses 3 SCAN listeners should be created
- SCAN VIP and SCAN Listener works as a pair when SCAN VIP fails over to other node, the corresponding 
  SCAN listener will also be failed over to the same node
- If SCAN listeners are up and running you should be able to ping them

Problem: For a SCAN returning 3 IP addresess only 2 SCAN listeners are created –> ping fails

[root@grac43 ~]# nslookup grac4-scan
Server:        192.168.1.50
Address:    192.168.1.50#53

Non-authoritative answer:
Name:    grac4-scan.grid4.example.com
Address: 192.168.1.170
Name:    grac4-scan.grid4.example.com
Address: 192.168.1.165
Name:    grac4-scan.grid4.example.com
Address: 192.168.1.168
--> For SCAN name  grac4-scan 3 IP addresses were returned - Verify with ping 
[root@grac43 ~]# ping -c 2 192.168.1.170
PING 192.168.1.170 (192.168.1.170) 56(84) bytes of data.
64 bytes from 192.168.1.170: icmp_seq=1 ttl=64 time=0.015 ms
64 bytes from 192.168.1.170: icmp_seq=2 ttl=64 time=0.021 ms
--- 192.168.1.170 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.015/0.018/0.021/0.003 ms

[root@grac43 ~]# ping -c  2 192.168.1.165
PING 192.168.1.165 (192.168.1.165) 56(84) bytes of data.
64 bytes from 192.168.1.165: icmp_seq=1 ttl=64 time=0.010 ms
64 bytes from 192.168.1.165: icmp_seq=2 ttl=64 time=0.231 ms
--- 192.168.1.165 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 999ms
rtt min/avg/max/mdev = 0.010/0.120/0.231/0.111 ms
[root@grac43 ~]#  ping -c  2 192.168.1.168
PING 192.168.1.168 (192.168.1.168) 56(84) bytes of data.
From 192.168.1.103 icmp_seq=1 Destination Host Unreachable
From 192.168.1.103 icmp_seq=2 Destination Host Unreachable
--> Ping is not working for for IP address 192.168.1.168
--- 192.168.1.168 ping statistics ---
2 packets transmitted, 0 received, +2 errors, 100% packet loss, time 3007ms
pipe 2
--> Ping fails for 1 of 3 IP addresses

Verify SCAN listener Setup

[root@grac41 network-scripts]# srvctl config scan_listener
SCAN Listener LISTENER_SCAN1 exists. Port: TCP:1521
SCAN Listener LISTENER_SCAN2 exists. Port: TCP:1521
--> Only 2 SCAN Listerns  
[root@grac41 network-scripts]#   srvctl config scan
SCAN name: grac4-scan.grid4.example.com, Network: 1/192.168.1.0/255.255.255.0/eth1
SCAN VIP name: scan1, IP: /grac4-scan.grid4.example.com/192.168.1.165
SCAN VIP name: scan2, IP: /grac4-scan.grid4.example.com/192.168.1.170
--> Only 2 SCAN VIPs

Recreate SCAN listener

[grid@grac41 ~/NET]$  srvctl stop scan_listener
[grid@grac41 ~/NET]$  srvctl stop scan

Verify OLD configuration: 
[grid@grac41 ~/NET]$ srvctl config scan_listener
SCAN Listener LISTENER_SCAN1 exists. Port: TCP:1521
SCAN Listener LISTENER_SCAN2 exists. Port: TCP:1521
[grid@grac41 ~/NET]$  srvctl config scan
SCAN name: grac4-scan.grid4.example.com, Network: 1/192.168.1.0/255.255.255.0/eth1
SCAN VIP name: scan1, IP: /grac4-scan.grid4.example.com/192.168.1.165
SCAN VIP name: scan2, IP: /grac4-scan.grid4.example.com/192.168.1.170

Modify and recreate SCAN listeners
[root@grac41 NET]#  srvctl modify scan -n  grac4-scan.grid4.example.com
[root@grac41 NET]#  srvctl config scan
SCAN name: grac4-scan.grid4.example.com, Network: 1/192.168.1.0/255.255.255.0/eth1
SCAN VIP name: scan1, IP: <not assigned>
SCAN VIP name: scan2, IP: <not assigned>
SCAN VIP name: scan3, IP: <not assigned>

[root@grac41 NET]# srvctl modify scan_listener -u
[root@grac41 NET]# srvctl config scan
SCAN name: grac4-scan.grid4.example.com, Network: 1/192.168.1.0/255.255.255.0/eth1
SCAN VIP name: scan1, IP: <not assigned>
SCAN VIP name: scan2, IP: <not assigned>
SCAN VIP name: scan3, IP: <not assigned>
[root@grac41 NET]#  srvctl config scan_listener
SCAN Listener LISTENER_SCAN1 exists. Port: TCP:1521
SCAN Listener LISTENER_SCAN2 exists. Port: TCP:1521
SCAN Listener LISTENER_SCAN3 exists. Port: TCP:1521
[root@grac41 NET]# srvctl start scan_listener
[root@grac41 NET]# srvctl config scan
SCAN name: grac4-scan.grid4.example.com, Network: 1/192.168.1.0/255.255.255.0/eth1
SCAN VIP name: scan1, IP: /grac4-scan.grid4.example.com/192.168.1.171
SCAN VIP name: scan2, IP: /grac4-scan.grid4.example.com/192.168.1.251
SCAN VIP name: scan3, IP: /grac4-scan.grid4.example.com/192.168.1.173

Verify that SCAN listeners are responding 
[root@grac41 NET]# ping 192.168.1.171
PING 192.168.1.171 (192.168.1.171) 56(84) bytes of data.
64 bytes from 192.168.1.171: icmp_seq=1 ttl=64 time=0.021 ms
64 bytes from 192.168.1.171: icmp_seq=2 ttl=64 time=0.024 ms
--- 192.168.1.171 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1411ms
rtt min/avg/max/mdev = 0.021/0.022/0.024/0.005 ms

[root@grac41 NET]#  ping  192.168.1.251
PING 192.168.1.251 (192.168.1.251) 56(84) bytes of data.
64 bytes from 192.168.1.251: icmp_seq=1 ttl=64 time=2.02 ms
64 bytes from 192.168.1.251: icmp_seq=2 ttl=64 time=1.47 ms
--- 192.168.1.251 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1121ms
rtt min/avg/max/mdev = 1.477/1.750/2.023/0.273 ms

[root@grac41 NET]# ping 192.168.1.173
PING 192.168.1.173 (192.168.1.173) 56(84) bytes of data.
64 bytes from 192.168.1.173: icmp_seq=1 ttl=64 time=2.62 ms
64 bytes from 192.168.1.173: icmp_seq=2 ttl=64 time=0.368 ms
^C
--- 192.168.1.173 ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1378ms
rtt min/avg/max/mdev = 0.368/1.498/2.629/1.131 ms

--> Prolbem fixed !

Verify  GNS scan-vip addresses

[root@grac41 NET]# srvctl config gns -a -l
GNS is enabled.
GNS is listening for DNS server requests on port 53
GNS is using port 5353 to connect to mDNS
GNS status: OK
Domain served by GNS: grid4.example.com
GNS version: 11.2.0.4.0
GNS VIP network: ora.net1.network
Name            Type Value
grac4-scan      A    192.168.1.171
grac4-scan      A    192.168.1.173
grac4-scan      A    192.168.1.251
grac4-scan1-vip A    192.168.1.171
grac4-scan2-vip A    192.168.1.251
grac4-scan3-vip A    192.168.1.173
grac41-vip      A    192.168.1.167
grac42-vip      A    192.168.1.178
grac43-vip      A    192.168.1.177

Reference

One thought on “How to recreate SCAN listeners to align nslookup IP adresses and SCAN listeners”

  1. Helmut, AWESOME site. Thank you for putting all of this together. I’ve bookmarked and will return often.
    -dave hays

    Reply

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