Changing application and DB connectivity in EBS 12.2.5

[Vijay]

Hi,
We are planning to implement a global traffic manager in our environment. Currently we are connecting to DB hostname.

We are planning to use GTM(global traffic manager) and resolve the hostname through GTM.

PLease suggest.

Current architecture APP1,App2,APP3,APP4 ==>> DB HOSTNAME

Planned architecture APP1,App2,APP3,APP4 ==>>GTM ==> DB HOSTNAME(GTM will resolve to DB hostname)

[ErmanArslansOracleBlog]

First, please tell me your reason to implement GTM for the connections to EBS's DB layer..
please tell your reason with details.

[Vijay]

Hi Erman,
Many thanks for your response. We are planning to use "DNS name resolution instead of /etc/hosts".

As  the client wants to move from /etc/hosts resolution to DNS resolution.

GTM configuration will be at DNS level.

[ErmanArslansOracleBlog]

Dont you have a DNS already?
Dont you use RAC for the DB level?

[Vijay]

Hi Erman,
Thanks for reply.

We are not using DNS. we have DB instance as Active/Passive.
 we are using /etc/hosts resolution.

[ErmanArslansOracleBlog]

Okay..
You will use the same hostnames in GTM right?
I mean the same hostnames that you have for your EBS in your client's and application node's /etc/hosts..
If so, it is easy.
Just configure your GTM with those hostnames and ip addresses and configure your DB+APP Operating Systems for the GTM..  That's all.
It should be transparent to the database side.
What you are talking about is F5 Load Balancer's module called GTM right?
Basically, during normal operations, the GTM can be configured with the production site's DNS name. When a DNS switchover is required, this mapping in the GTM is changed to map to the standby or passive site 's IP. This allows requests to be directed to the standby or passive site, which now has the production role.

I didn't exactly understand what you are asking to me about this?

[Vijay]

Hi Erman,
We have following situation.

1. There is no change in Application hostname or I.P.
2. There is no change in database hostname or I.P.
3. GTM(Global traffic manager) will route the traffic to database nodes from respective nodes.

Current architecture : APP1,APP2,APP3,APP4 ==>> DB HOSTNAME

Planned architecture : APP1,APP2,APP3,APP4 ==>>GTM ==> DB HOSTNAME(GTM will resolve to DB hostname)

For implementation of GTM in other standalone,Active passive environments we performed following steps.

1. Network team gave us a GTM ID. Which resolved to the DB IP/host and port.  
2. We changed the HOST entry in TNSNAMES.ora  to GTM provided. application worked fine.  

[ErmanArslansOracleBlog]

Yes...
It should be transparent to Oracle . ( both App tier and DB tier)
App and DB tier should only operate with IPs and hostnames..
GTM , which is the man in the middle should do its work without affecting Oracle.
so the configuration that you need to make is in GTM.
You need to configure your GTM according to your Oracle deployment.

If GTM needs somethings to be configured in Oracle level, then you can get a downtime and do it.. (like you said, updating the tnsnames.ora)

Bytheway, ensure your updates are autoconfig persistent..
I mean, ensure your updates will not be overwritten after an autoconfig run.
We do these kinds of updates in IFILEs , as you know..

[Vijay]

Hi Erman,
Thanks for your support. We concluded as follows.

1. We need to implement GTM/load balancer at network level for EBS environment.
2. FND_NODES tables need I.P. address and hostname for app/db connectivity.
3. Changing the hostname in tnsnames will be overwritten when we will run the autoconfig utility again.
4. Host entry for DB is required in application servers for application connectivity.  

[ErmanArslansOracleBlog]

So?

[Vijay]

Hi Erman,
My message was not complete in the last update.

We have asked our network team to implement it at load balancer level.

GTM implementation at application level is not possible.

Thanks for your kind reply and support.