PRVF-4664 Prvf-4657:found Inconsistent name resolution entries for SCAN name (document ID 887471.1)

In this Document

Applies To:

Oracle server-enterprise edition-version 11.2.0.1 to 11.2.0.3 [Release 11.2]
Information in this document applies to any platform.

Purpose

Runinstaller (OUI) reports INS-20802 while running Oracle Cluster verification Utility Post check after successful 11gR2 G Rid Infrastructure clusterware (CRS) installation or upgrade:

• 
  Installation log-$ORACLE _base/orainventory/logs/installactions{$TIMESTAMP}.log

INFO: PRVG-1101 : SCAN name "cluscan.us.oracle.com" failed to resolve
Info:error:
INFO: PRVF-4664 : Found Inconsistent name resolution entries for SCAN name "Cluscan.us.oracle.com"
Info:error:
INFO: PRVF-4657 : Name resolution Setup Check for "SCANCLUNM" (IP address:10.4.0.202) failed

OR

PRCS-1016 : Failed To resolve single Client Access Name cluscan.us.oracle.com

If "$GRID _home/bin/cluvfy Comp Scan" is executed, similar message would be reported.

Details

cause 1. SCAN name is expected to being resolved by local Hosts file

SCAN name is resolved by local Hosts file (/etc/hosts or%systemroot%\system32\drivers\etc\hosts) instead of DNS or GNS

Solution: Oracle strongly recommend to use DNS or GNS for SCAN name resolution as hosts file support only one IP For SCAN

If the intention is to use Hosts file for SCAN name resolution, and ping command returns correct SCAN VIP, can ignore The error and move forward.

If the intention is to use DNS or GNS for Scan name resolution, comment out entries in local Hosts file for scan name on a ll nodes, and re-run "$GRID _home/bin/cluvfy Comp Scan" to confirm.

cause 2. Nslookup fails to find record for SCAN name:

nslookup cluscan.us.oracle.com
..

* * Server can ' t find Eotcs.us.eot.com:NXDOMAIN

Solution: Engage System Administrator (SA) to check resolver configuration (/etc/resolv.conf on Linux/unix), correct a NY misconfiguration on all nodes and re-run "$GRID _home/bin/cluvfy Comp Scan" to confirm.


Cause 3. SCAN name is canonical name (CNAME record) in DNS

nslookup  cluscan.us.oracle.com
:
cluscan.us. oracle.com     canonical name =  cluscan.a3. oracle.com
name:   cluscan.a3.oracle.com
address:10.4.0.201
name:   cluscan.a3.oracle.com
address:10.4.0.202
name:   cluscan.a3.oracle.com
address:10.4.0.203

solution: Engage SA to update SCAN record in DNS to A type instead of CNAME type.


cause 4. DNS is configured properly in DNS if other naming Resolution (NIS, LDAP:) is being used and doesn ' t has proper SCAN info

solution: Engage SA to check name resolution switch configuration (/etc/nsswitch.conf on Linux, Solaris and HP-UX Or/etc/netsvc.conf on AIX) and correct any misconfiguration on all nodes. Example hosts in nsswitch.conf:

Hosts:files DNS NIS

Once it ' s corrected, execute "$GRID _home/bin/cluvfy Comp Scan" to confirm


cause 5. Persistent cache for NSCD have incorrect information.

solution: Engage SA to restart NSCD and clear persistent cache on all nodes. Example on Linux

#/sbin/service NSCD Restart
#/USR/SBIN/NSCD--invalidate=hosts

Once it ' s corrected, execute "$GRID _home/bin/cluvfy Comp Scan" to confirm.

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What's the expected output when executing nslookup

nslookupCluscan.us.oracle.com

..
Name:cluscan.us.oracle.com
address:10.4.0.201
Name:cluscan.us.oracle.com
address:10.4.0.202
Name:cluscan.us.oracle.com
address:10.4.0.203


Ping-C 1 cluscan.us.oracle.com
PING cluscan.us.oracle.com (10.4.0.201) bytes of data.
Bytes from cluscan.us.oracle.com (10.4.0.201): icmp_seq=1 ttl=64 time=0.258 ms

---cluscan.us.oracle.com ping statistics---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
RTT Min/avg/max/mdev = 0.258/0.258/0.258/0.000 ms

Ping-C 1 cluscan.us.oracle.com
PING cluscan.us.oracle.com (10.4.0.202) bytes of data.
Bytes from cluscan.us.oracle.com (10.4.0.202): icmp_seq=1 ttl=64 time=0.258 ms

---cluscan.us.oracle.com ping statistics---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
RTT Min/avg/max/mdev = 0.258/0.258/0.258/0.000 ms

Ping-C 1 cluscan.us.oracle.com
PING cluscan.us.oracle.com (10.4.0.203) bytes of data.
Bytes from cluscan.us.oracle.com (10.4.0.203): icmp_seq=1 ttl=64 time=0.258 ms

---cluscan.us.oracle.com ping statistics---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
RTT Min/avg/max/mdev = 0.258/0.258/0.258/0.000 ms

From above-can see:

1. Nslookup is returning proper SCAN name and IPs
2. Ping to SCAN name are Round Robin resolved to different IPs each time by DNS

If you see the different behaviour than above, please engage SAS to investigate.
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Ping Command Reference

Linux:/bin/ping-c 1 cluscan.us.oracle.com
Solaris:/usr/sbin/ping-s cluscan.us.oracle.com 1500 1
HP-UX:/usr/sbin/ping cluscan.us.oracle.com-n 1
AIX:/usr/sbin/ping-c 1 cluscan.us.oracle.com
Windows:ping-n 1 cluscan.us.oracle.com

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References

bug:8901977 -cluvfy prvf-4664:found inconsistent name RESOLUTION ENTRIES for SCAN name
note:887522.1 -11gR2 Grid Infrastructure single Client Access Name (SCAN) explained

This article is from "Technical achievement dream!" "Blog, be sure to keep this provenance http://dreamsanqin.blog.51cto.com/845412/1665696

PRVF-4664 Prvf-4657:found Inconsistent name resolution entries for SCAN name (document ID 887471.1)