| Can I configure an 11gR1 RAC to redirect to different hostnames/IP's based on services [message #553081] |
Tue, 01 May 2012 12:19  |
meclo
Messages: 4
Registered: May 2012
Location: Canada
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Junior Member |
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Hi all,
Long time listener (no pun intended!), first time caller here.
I have an interesting dilemma that I'm trying to work through, and was hoping someone could offer guidance.
I have a 2-node Oracle Standard 11gR1 RAC that is sitting in our DMZ, which will be accessed by both internal and external (internet) clients. Is it possible to configure different RAC database services (one internal, one external) and have the services redirect to different hostnames or IP's (internal IP address/hostname vs external IP address)?
The problem I'm seeing is that if an instance redirect has to occur (Ex. if client initially connects to instance01 but is redirected to instance02 because that's where the service is currently active), the RAC will pass back the VIP hostname where the instance resides, which an external client won't be able to resolve (even if the tnsnames.ora file on the client has IP's instead of hostnames).
Perhaps my issue is understanding how the RAC gets the hostname to pass back to the client; I thought that came from the local_listener parameter within the database but my experimentation seems to have proven that theory wrong.
The simplest solution to this would probably be a local host entry or DNS alias at the client sites, but I'm not sure this is possible (we're communicating with our clients about this now but we've encountered some resistance).
Any insight into how to deal with this would be greatly appreciated.
Thanks!
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| Re: Can I configure an 11gR1 RAC to redirect to different hostnames/IP's based on services [message #553087 is a reply to message #553086] |
Tue, 01 May 2012 14:34  |
meclo
Messages: 4
Registered: May 2012
Location: Canada
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Junior Member |
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The hostnames for my RAC nodes are "ext-racnode01.domain.com" and "ext-racnode02.domain.com". The RAC VIP's are called "ext-racvip01" and "ext-racvip02". In the event that the RAC has to redirect a client connection to a different instance, is there a way to configure the RAC to redirect to "ext-racvip0x.domain.com" instead of just "ext-racvip0x"? I'm assuming this is done from within the RAC somewhere, since the "ext-racvip0x" names are not configured anywhere outside of the RAC clustering software (as far as I know). Let me know if I'm mistaken.
Thanks!
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| Re: Can I configure an 11gR1 RAC to redirect to different hostnames/IP's based on services [message #553128 is a reply to message #553087] |
Wed, 02 May 2012 01:31 |
John Watson
Messages: 8963
Registered: January 2010
Location: Global Village
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Senior Member |
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This is a bit confused, but I'll try.
First, as BS says, it is IP addresses that matter, not names.
Second, you are using 11.1, so the fixed and virtual names are static and resolved in hosts files and/or DNS (it will be different when you upgrade to 11.2)
Third, release 11.1 clusterware can really only failover one IP address per node. So you will almost certainly NOT be able to have automatic VIP failover for both networks. You'll have to manage your VIPs manually.
Fourth, directing the sessions using services is easy. Configure your listeners to listen on both the internal and external address, and create two services: make each sevice "preferred" on one node and "available" on the other.
hth, John.
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| Re: Can I configure an 11gR1 RAC to redirect to different hostnames/IP's based on services [message #553179 is a reply to message #553128] |
Wed, 02 May 2012 08:29 |
meclo
Messages: 4
Registered: May 2012
Location: Canada
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Junior Member |
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Thanks John and BlackSwan for your replies. I've read a bit about SCAN and it seems like that might have been helpful in this situation, but there's nothing to be done about that (at this point anyway).
I was able to get the RAC to redirect to the FQDN rather than the hostname; the solution was in the tnsnames.ora file after all, I just needed to restart the database along with the listeners (didn't know that). So I think I'll be alright once I get our network guy to add the hostnames to our external DNS and make those names resolvable from the outside.
Cheers!
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