In Enterprise Manager Cloud Control 12c Release 1 (12.1.0.1) and 12c Release 2 (12.1.0.2), by default the agent base directory of the central agent is maintained inside the Oracle Middleware Home (middleware home). Central agent is the Oracle Management Agent that is deployed by default with the first Oracle Management Service (OMS).
However, in Enterprise Manager Cloud Control 12c Release 3 (12.1.0.3) or higher, Oracle strongly recommends that you maintain the agent base directory outside the middleware home, although you can choose to maintain it inside the middleware home. Each 12c upgrade is an out-of-place upgrade that results in a new middleware home created for the upgraded release. By maintaining the agent base directory outside the middleware home, you do not have any dependency on the previous release's middleware home, and therefore, you can conveniently delete the previous releases's middleware home when it is not needed.
Therefore, when you install a new 12c Release 3 (12.1.0.3), 12c Release 4 (12.1.0.4), or 12c Release 5 (12.1.0.5) OMS, you will see the central agent base directory created outside the middleware home by default (unless you chose to maintain it inside the middleware home). Similarly, when you upgrade from a newly installed 12c Release 3 (12.1.0.3) or 12c Release 4 (12.1.0.4) OMS to 12c Release 4 (12.1.0.4) or 12c Release 5 (12.1.0.5), respectively, you will see the agent base directory upgraded outside the middleware home by default (unless you chose to maintain it inside the middleware home in the previous releases).
However, when you upgrade from 12c Release 1 (12.1.0.1) to 12c Release 2 (12.1.0.2) or 12c Release 3 (12.1.0.3), and then upgrade to 12c Release 4 (12.1.0.4) or 12c Release 5 (12.1.0.5), you will continue to see the central agent base directory inside the middleware home (unless you had not already migrated it outside the middleware home). You can choose to migrate the central agent base directory to a location outside the middleware if you want.
Note that moving the central agent base directory outside the Oracle Middleware home is a one-time activity. Once the central agent base directory is moved outside the middleware home, it remains at the same location even after subsequent upgrades.
If a central agent was upgraded to 12.1.0.2 (from 12.1.0.1) or 12.1.0.3 (from 12.1.0.1 or 12.1.0.2), and you want to move the central agent base directory outside the Oracle Middleware home, then follow the instructions outlined in the My Oracle Support note 1520010.1.
If you want to move the agent base directory of a 12.1.0.5 or 12.1.0.4 central agent (which was initially of version 12.1.0.1, then upgraded to 12.1.0.2, 12.1.0.3, and then again upgraded to 12.1.0.4 or 12.1.0.5, respectively) to a location outside the middleware home, follow these steps:
Important:
Moving the agent base directory is recommended only for the central agent, and not for the other Management Agents.
Moving the agent base directory is not supported on a host that is running on Microsoft Windows.
Run the following script:
<AGENT_HOME>/perl/bin/perl <AGENT_HOME>/sysman/install/create_plugin_list.pl -instancehome <AGENT_INSTANCE_HOME>
Here, <AGENT_HOME> represents the current central agent Oracle home, and <AGENT_INSTANCE_HOME> represents the current central agent instance home.
Edit the agentimage.properties file and set the SBIN_MODIFIED_VERSION parameter to 12.1.0.5.0.
<AGENT_BASE_DIRECTORY>/agentimage.properties
Run the following script:
<AGENT_HOME>/perl/bin/perl <AGENT_HOME>/sysman/install/ConvertToStandalone.pl -instanceHome <AGENT_INSTANCE_HOME> -newAgentBaseDir <AGENT_BASE_DIRECTORY>
Here, <AGENT_HOME> represents the current central agent Oracle home, <AGENT_INSTANCE_HOME> represents the new central agent instance home, and <AGENT_BASE_DIRECTORY> represents the location to which you want to migrate the central agent base directory.
To verify whether the migration was successful, switch to the Cloud Control console and perform these steps:
From the Targets menu, select All Targets. Select the central agent target. On the Management Agent home page, in the Summary section, verify the Oracle home path and the agent state directory path. Ensure that both these paths point to the new locations.
Access the home pages of the targets monitored by the central agent. Check the status of these targets. Ensure that they are up and running.