reg bounce

[satish]

Dear Erman,

We are using 2 node application and 2 node database.

Is it possible to bounce oacore with no impact to already connected users?

Thanks,
satish

[ErmanArslansOracleBlog]

I guess you are asking a rolling bounce.
I mean, stop oacore 1 and start oacore 1 , then stop oacore 2 and start oacore2

EBS uses Weblogic, as you know.
your multiple oacore managed servers are clustered.
so this subject is a matter of Weblogic clustering.
Weblogic clusters have the ability of providing Application Failover. This means that when an application component doing a particular "job" becomes unavailable for any reason, a copy of the failed object finishes the job.
But, this needs to be tested with EBS 12.2. This is not documented, and I think, the capability above depends on the code of the application as well.

Why don't you do a test, and update me?

[satish]

Dear Erman,

I tried this.Brought down oacore1 on node1 and few users reported the error " Transaction context lost".

[satish]

This is how i have tested.

1)Opened a JSP page through multiple systems and browsers
XML Publisher->HOME->Template

2)Brought down oacore_server1 on node 1

3)Clicked on data definitions on the same page,then i got the attached error


so i have 2 oacores on same node and 2 on other node.when i bring down 1 oacore process,why dont the other process pick it up?

Thanks all the support you provide

[satish]

WebLogicServerUtility.docx

[satish]

I have raised an SR but it is not going in a right way.I am confident that you can help me here.with my experiment it is not possible to perform oacore managed serves bounce without any impact to connected users.

can you please correct me if i am wrong and also please let us know if we can do something to make it possible

[ErmanArslansOracleBlog]

I agree with you.. Connected users will get errors.
In the WLS side, however; there are things that can be done.
For example, in SOA documentation, we see the following:

"To resume transactions after a server migration, configure the transaction and JMS stores in a shared storage. In case of failure in one of the server infrastructure instances, other instances can resume transactions and JMS operation by reading the persistent stores from that shared storage."

Well.. As this is not documented for EBS, I suggest you to follow your SR.
Interesting case.. Please update me with the outcome.

[satish]

Sure erman.

Below is the update from SR

Usually the Load Balancer should balance the users from first oacore to second oacore.
If the Load Balancer is not configured correctly, as it is on your side, than this will not work properly and some errors will occur.
Also if the load is very high the second oacore can have problems, but this depends on the load.

Is the below statement true?

Usually the Load Balancer should balance the users from first oacore to second oacore.

[ErmanArslansOracleBlog]

The correct statement is Load balancer should manage the load .. It should also prevent losing transaction state when one of your apps node fails.

Good point..

so , in this case, the key is the configuration of the load balancer..

Here is what Oracle says about it:

The Hardware Load Balancer must be configured for session persistence: various modules shipped with Oracle E-Business Suite need to maintain session state.  If this property is not set, the loss of transaction state may result in users experiencing unpredictable errors.
Oracle supports session persistence technology that is transparent to the Oracle E-Business Suite; that is, session persistence approaches which do not require additional programmatic changes to the underlying E-Business Suite modules. For successful integration of your load balancer with Oracle E-Business Suite application tiers, refer to your load balancer's documentation for details on how to configure the load balancing pool, virtual host configuration, and session persistence parameters.

Read ->

Using Load-Balancers with Oracle E-Business Suite Release 12.2 (Doc ID 1375686.1)
2.2.5: Configuration Changes on the Load Balancer

Make your Load Balancer admin to check the configuration of the load balancer accordingly..

[satish]

Thanks for the update.

For suppose,If we correct the configuration of load balancer.
If i bring down oacore1 then the users will be migrated to some other oacores which is available?is this possible?

[ErmanArslansOracleBlog]

Yes , it should be so. as Oracle says:

Oracle supports session persistence technology that is transparent to the Oracle E-Business Suite; that is, session persistence approaches which do not require additional programmatic changes to the underlying E-Business Suite modules.

So, if the load balancer does its job properly, transaction states will not be lost. That's why, users will not experience unpredictable errors.

In other words, if the load balancer can do session persistence, then users will not experience unpredictable error when one node goes down..

Session Persistence:

Session Persistence is the act of keeping a specific user's traffic going to the same server that was initially hit when the site was contacted for the first HTTP transaction. This is especially important for E-Business Suite as various modules bundled with the suite need to maintain session state.  Session persistence is sometimes referred to as "server stickiness."

But , this needs to be tested and verified!

[satish]

Thanks erman.I will try to test it and update here

[satish]

Dear Erman,

Support engineer has updated "The LB must have as Load Balancing Method - Predictive Node Address" which in our case we dont have that option in our load balancer.so we have to buy some other load balancer which supports it

However,we just wanted to know if the below are possible


1)If we get a load balancer suitable for EBS,then can we perform rolling bounce without any impact to existing users?
2)if some dml is happening in OAF page and suddenly if a specific oacore related to that went down,then in this case will the other oacore process running on the same node takes that and complete it?

we understand that this needs to be tested but still need your thoughts.

Thanks all the support

[ErmanArslansOracleBlog]

The requirement of predictive Node Address is documented in "Using Load-Balancers with Oracle E-Business Suite Release 12.2 (Doc ID 1375686.1)" , "section 2.1.4: Configuration Changes on the Load Balancer"

However, I m not sure if it can provide you what you are looking for.

What I believe is , your solution is in the Load Balancer side. So It seems it is all about Load Balancer configuration..