While setting up Oracle 12c RAC in the Nutanix performance labs and using GNS for name resolution I ran into a few issues with some cryptic error messages. Multiple Google searches yielded nothing helpful. Most people I talked to said they hadn’t used GNS before. It took me a little while to figure it out and now I have I’d like to save you the trouble.

I worked my way through the usual Oracle 12c Grid Infrastructure install and made sure all the pre-req’s were sorted out. Clicked the install button and went away to make a coffee. When I got back it wasn’t complete as I had expected, there was an error message saying that the root scripts had failed to execute. On further inspection through the detailed logs there was a message saying that GNS could not be configured because the domain name was invalid. In the Nutanix lab I had used a domain ending nxmgmt.local.

At first I thought this was a problem with my DNS servers, or the domain delegation that I had created. I tried a few things, such as restarting the DNS servers, trying to resolve the names and IP’s of the various components. Then I stepped back for a second and wondered if the way that Oracle RAC and GNS uses mDNS (multicast DNS) could be contributing to the problem. It was at this point that I thought, I wonder if using .local as the top level domain (TLD) is the problem as that is used by IPV6 and mDNS for name resolution.

At this point I decided to set up a new top level domain in my DNS servers and try the installation again. I set up the TLD .test. The GNS delegated domain would be nxrac.test, and my cluster would be nxrac-cluster, with SCAN of nxrac-cluster-scan.nxrac.test. I figured up the GRID installer again and this time everything went through without a hitch.

Final Word

This was an annoying problem to run into. But didn’t take too long to solve. If this article prevents just one other person from running into the same problem, it will have been worth the experience. Now that I’ve got my RAC set up I can get on with running SLOB to do a few simple tests.

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This post first appeared on the Long White Virtual Clouds blog at longwhiteclouds.com. By Michael Webster +. Copyright © 2012 – 2016 – IT Solutions 2000 Ltd and Michael Webster +. All rights reserved. Not to be reproduced for commercial purposes without written permission.