Installing Oracle Enterprise Manager Cloud Control 12c

This is a brief guide to installing Oracle Enterprise Manager 12c on Oracle Linux 

Stage 1 - Checking the Prerequisites

We need at least 150GB of storage space to install the Database and Enterprise Manager successfully.

Next we need to check what value the maximum user process limit is set to. To do this we need to open the terminal and run the following command " ulimit -n " if the value returned by the command is 13312 or greater then skip the next step. As can be seen in the image below on a fresh installation of Oracle Linux the value returned is 1024. Below the limit needed.


To change this limit, we need to edit the /etc/security/limits.conf file as root and make the following changes or add the following lines, respectively: 

oracle soft nofile 4096

oracle hard nofile 63536

Once that has been completed we can then download the Databse and Enterprise Manager software from the 

Oracle Technology Network

Database Installation

Before installing the database we need to create directories to hold the downloaded zip files,the Oracle software and change the owner to the Oracle user.

mkdir -p /u01/install
chmod -R 775 /u01/install
chown -R oracle:oinstall /u01/install

mkdir -p /u01/app/oracle
chmod -R 775 /u01/app/oracle
chown -R oracle:oinstall /u01/app/oracle

Ensure that everything from /u01 downwards has the correct ownership and permissions.

Also check that tmpfs in /etc/fstab looks like this:

tmpfs /dev/shm /tmpfs rw, exec 0 0

Once the files have been downloaded to the install directory we need to unzip them. Then after ensuring that these files are owned by oracle, enter the following as root

$ xhost si:localuser:oracle

so that the Oracle user can run xhost without which the Oracle Universal Installer (OUI) will be unable to run.

Then we need to navigate to the directory where the database software has been unzipped to and run the Oracle Universal Installer (OUI) by typing


from a terminal window. Select the option for software only installation.

After the installation has been completed we need to download the Database Temple from the OTN. As we are installing this on linux we will need the "" file. Once the file has been downloaded we then need to extract it to this location on the Database Host. $<DB_HOME>/assistants/dbca/templates


Create the database by running the database configuration assistant from <DB_HOME/bin/dbca. On the database template screen, select the template that matches the deployment size of your choice.

While installing the database we need to make sure that the global database name is the same as the systems host and domain names

Installing Enterprise Manager

Now we can start the installation wizard. 

My Oracle Support

The first screen we see after starting the installer, is the My Oracle Support Details screen. We need to enter our support credentials to enable the Oracle Configuration Manager. Or leave the fields blank and hit the next button.

Install Software Updates

On the Software updates screen, select search for updates and then choose one of the following options to apply the latest software updates:

  • Local Directory, if there is no internet connectivity on your host and you  want the updates to download in offline mode and apply them while performing the installation
  • My Oracle Support, if you have Internet connectivity on your host, and want to connect to My Oracle Support directly via the installer to download the updates in online mode and apply them while performing the installation..

Or we can skip this step 

Click the next button to proceed.

(For more information on these options, and for instructions to download and apply the software updates using these options, see Oracle Enterprise Manager Cloud Control Advanced Installation and Configuration Guide.)

Check Prerequisites

On the Prerequisite Checks screen, the installation wizard runs the prerequisite checks automatically when we come to this screen. It checks for the required operating system patches, operating system packages, and so on.

The status of the prerequisite check can be either Warning, Failed, or Succeeded.

  • If some checks result in Warning or Failed status, then investigate and correct the problems before you proceed with the installation. The screen provides details on why the prerequisites failed and how we can fix them. After you correct the problems, return to this screen and click Rerun to check the prerequisites again.
  • However, all package requirements must be met or fixed before proceeding any further. Otherwise, the installation might fail.

Click the next button to continue

Select Installation

On this screen we just need to choose "Create a New Enterprise Manager system" and select simple. 

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Installation Details

On this screen we need to enter the path of the Middleware home where we want to install the OMS and other core components, eg: /u01/software/em/middleware

Then enter the absolute path to the agent base directory, which is a location outside the Oracle Middleware home where the Management Agent can be installed. For example if the middleware home is /u01/software/em/middleware then the agent directory can be specified as /u01/app/oracle/agent12c.

Double check to ensure that the locations are empty and that the oracle user has write permissions to them.

Then we need to enter the name of the host where we want to configure the oms, which in this case is the host we have already installed the database on.

Configuration Details

On the configuration details screen we need to do the following:

  • Enter an administrator password, which can be used as a common password for configuring the Enterprise Manager Cloud Control. It's essential that we do not forget this password later on. Otherwise we will need to re-install the Enterprise Manager
  • Enter the details of the existing database where the Management Repository needs to be created. If (as we did earlier) there is already a database that has been created with a preconfigured Management Repository using the database templates, then we need to input the details about that database instance.

If this error pops up when clicking next


then we will need to connect to the database as the sysdba and enter the following command “ALTER SYSTEM SET db_securefile=PERMITTED SCOPE=BOTH;”

Review and Install

On this screen, we have a final chance to review the details that we provided for the selected installation type, checking for any errors entered in the previous screens before continuing.

  • If you want to change the details, click Back repeatedly until you reach the screen where you want to make the changes.
  • After verifying the details, we can then click Install to begin the installation process.

After this you can sit back and relax for a while as the Enterprise Manager is installed.

Tracking the Installation Progress

On the Install Progress screen, we can view the overall progress (in percentage) of the installation and the status of each of the configuration assistants.

Run Scripts

At some point during the installation we will be prompted to run the script, and the script if this is the first Oracle product installation on the host.

If the prompt appears we need to open another terminal window and log in as root to manually run the scripts.

Finishing the Installation

On the Finish screen, we should see information about the installation of Enterprise Manager. Review the information and click Close to exit the installation wizard.

For more information about this installation, refer to the following file available in the OMS home:


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