Autoconfig in Oracle Applications 11i & R12.

In Oracle Applications 11i & R12 (12i) all the configuration parameters are captured in two context files:
Application context file called the <CONTEXT_NAME>.xml contains the configuration information for the application tier & is located in $APPl_TOP/admin for each node of application tier.
Database context file called the <CONTEXT_NAME>.xml contains the configuration information for the database tier & is located in $ORACLE_HOME/appsutil/.
Details stored in the context file contains host names,domain name , directory structure, port numbers used  ……
The AutoConfig feature of Oracle application manager(OAM) is used to update & manage context files.
Updating Context file
Suppose we want to update the active port from <original port no.> to 80 , for this we will edit the application context file as follows:
Step 1 :Start all services
$ $COMMON_TOP/admin/scripts/<context_name>/adstrtal.sh APPS/<apps password>
$ADMIN_SCRIPTS_HOME/adstrtall.sh apps/appspwd.
Step 2 :log on to OAM & click site map.
Step 3:Click AutoConfig from the list of System Configuration features in the Administration tab.
Step 4 : Click the Edit Parameter button for the application tier context file to access the Context File Parameters page & then click the system tab.
Step 5 : Click the Focus icon (blue triangle) for oa_web_server. This expands oa_web_server and shows the web server related parameters.
Step 6:Update the Web Port (s_active_webport) parameter from < Original port number> to 80.
Step 7 : Save it & answer the tab.Then logout of OAM
AutoConfig Script
The autoconfig script uses information from the context file to generate all applications configuration files & updates database profiles. It is located in
Application tier: $COMMON_TOP/admin/scripts/CONTEXT_NAME/adautoconfig.sh
$ADMIN_SCRIPTS_HOME/adautocfg.sh

Database tier: $ORACLE_HOME/appsutil/scripts/CONTEXT_NAME/adautoconfig.sh
Now we run the autoconfig script to reconfigure the oracle application system with the updated Applications context.
Step 1 : Stop all services
$ $COMMON_TOP/admin/scripts/<context_name>/adstpall.sh APPS/<apps password>(OR)
$ADMIN_SCRIPTS_HOME/adstpall.sh apps/appspwd.
Step 2:Run the autoconfig script, $adautocfg.sh & respond to the prompts.
Step 3:Check log files for any errors.log file for autoconfig is adconfig.log & is located in
<APPL_TOP>/admin/<context_name>/log/MMDDhhmm/
Step 4: Restart all services :
$ $COMMON_TOP/admin/scripts/<context_name>/adstrtal.sh APPS/<apps password>(OR)
$ADMIN_SCRIPTS_HOME/adstrtall.sh apps/appspwd.
Rolling back an autoconfig session
Each execution of AutoConfig creates a roll back script in case you want to revert back to the previous configuration settings. For this we perform the following steps:
Step 1 :Shut down all services:
$ cd $COMMON_TOP/admin/scripts/<context_name>(OR)
$ADMIN_SCRIPTS_HOME/adstpall.sh apps/appspwd.
$ adstpall.sh APPS/<APPS password>
Step 2:Restore AutoConfig session.
$ cd $APPL_TOP>/admin/<context_name>/out/MMDDhhmm
$ restore.sh
Step 3 : Restart all services:
$ $COMMON_TOP/admin/scripts/<context_name>/adstrtal.sh APPS/<APPS password>(OR)
$ADMIN_SCRIPTS_HOME/adstrtall.sh apps/appspwd.
Restoring the AutoConfig updated files and restarting the services allows you to log on to OAM.

Restoring the previous configuration
Now we run OAM AutoConfig to restore the Applications Context.
Step 1 :Log on to the Oracle Application Manager (OAM) & click site map.You will be able to log on but some services will be down.
Step 2: Click AutoConfig from the list of System Configuration features in the Administration tab.
Step 3 : Click the Show History button for the application tier context file to access the Context File History page.
Step 4 :Click the Show Differences from Current Configuration button to see the recently updated parameters & Select Restore Previous Value for the Web Port and Discoverer Port parameters.
Step 5 :Save & respond the tabs. Log out of OAM.
Step 6 :Shut down all services:
$ cd $COMMON_TOP/admin/scripts/<context_name>(OR)
$ADMIN_SCRIPTS_HOME/adstpall.sh apps/appspwd
$ adstpall.sh APPS/<APPS password>
Step 7 :Run the AutoConfig script, adautocfg.sh & Respond to the prompts.
Step 8 : View the log file and check for any errors.
Step 9 : Restart all services:
$ $COMMON_TOP/admin/scripts/<context_name>/adstrtal.sh APPS/<APPS password>(OR)
$ADMIN_SCRIPTS_HOME/adstrtall.sh apps/appspwd.
Step 10 :Log on to the Oracle Application Manager (OAM)
If the status of some services appears to be down, click the Refresh icon to update the
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