Performing Prerequisite Tasks

Installing Oracle Linux Server on a Virtual Machine

This task describes how to install Oracle Linux Server on a virtual machine. You can skip this task if you already have Oracle Linux installed and running on a virtual machine.

Create a virtual machine in a suitable environment. Use Oracle VM VirtualBox or another suitable virtualization system. These instructions assume the use of VirtualBox.
Install Oracle Linux as a guest operating system for this virtual machine, using the latest update of Oracle Linux 7 Server software that you obtain from Oracle Software Delivery Cloud:
```
https://edelivery.oracle.com
```
Set a password for the root user.
Create a new administrative user, such as demoadmin (example).
Run the visudo command to provide superuser privileges (sudo access) to demoadmin.
Restart the virtual machine and log in as demoadmin.
(Optional) Take a snapshot of the virtual machine, which creates an entry of a step, to be able to get back to that step in the future.
1. Click Take to open the Take a Snapshot of Virtual Machine dialog box.
2. Give a name to the snapshot, such as Oracle Linux Installation and Upgrade.
Note: Later procedures also mention taking a snapshot at a particular point in the process. These are optional steps that give you a backup at each point, so that you can revert to a previous snapshot if you make a mistake.

Perform the remaining tasks in this section as demoadmin to further prepare the system for deploying the Siebel CRM containers.

Enabling Permissive Mode for SELinux

Security-Enhanced Linux (SELinux) is a Linux kernel module that supports access-control security policies. To facilitate your deployment process, it is recommended to change from enforcing to permissive mode, which means that you are warned about issues but that actions are not blocked. Consult your security team for specific requirements that might apply for your company. This is an optional step.

Enabling the ol7_addons Yum Repository

You must enable the Yum repository ol7_addons, which gives you access to install Docker.

First, use the following command to edit the file public-yum-ol7.repo:
```
sudo vi /etc/yum.repos.d/public-yum-ol7.repo
```

Within the [ol7_addons] section of the file public-yum-ol7.repo, set the Enable parameter to a value of 1, as shown in this example section of the file:

[ol7_addons]
name=Oracle Linux $releasever Add ons ($basearch)
baseurl=https://yum.oracle.com/repo/OracleLinux/OL7/addons/$basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle
gpgcheck=1
enabled=1

Installing the Docker Engine

Use the following command to install the Docker Engine using Yum:

sudo yum install -y docker-engine

Starting the Docker Service

Use the following commands to start the Docker service automatically and to restart it automatically when the virtual machine starts:

sudo systemctl start docker
sudo systemctl enable docker

Enabling the Administrative User

Enable the administrative user demoadmin to execute Docker commands. To do this, use the following command:

sudo usermod -aG docker demoadmin

You will need to log out and log in again before the permission is active.

Installing Git

Install the Git tool to allow pulling software from GitHub. To do this, use the following command:

sudo yum install -y git

Testing the Docker Engine and Git

Perform the following steps to test access to the Docker Engine and whether it is up and running.

Restart the virtual machine.
Log in to the Oracle Linux virtual machine as the demoadmin user.
Run the following command:
```
docker --version
```
For example, the response might be as follows:
```
Docker version 19.03.11-ol, build 9bb540d
```
Run the following command:
```
git --version
```
For example, the response might be as follows:
```
git version 1.8.3.1
```
(Optional) Take a snapshot: Prerequisites Completed.

Enabling VirtualBox Additions

Enable the VirtualBox additions on the virtual machine to improve the integration of the host (local computer) and the client (hosted virtual machine). Do the following to enable the VirtualBox additions:

Install kernel additions to enable the virtual machine to recognize the host's screen resolution. Use the following command:
```
sudo yum install kernel-uek-devel-$(uname -r) -y
```
Insert the VirtualBox Guest Additions CD using the menu option Devices > Insert Guest Additions CD Image.
Map the network drive using the menu option Devices > Shared Folders > Shared Folders Settings.

Mapping the directory on the host allows you to easily move any content from the host to the virtual machine.
Add the demoadmin user to the VirtualBox shared folders group so it has read and write access to the files in the shared folders. Use the following command:
```
sudo usermod -aG vboxsf demoadmin
```
Log off the client (virtual machine) and log in again.
Enable the transfer of container images between the host and the client (virtual machine). To do this, use the menu option Devices > Shared Clipboard > Bidirectional.

Later, you will copy content from the host (local computer where you are downloading the container images) to the client (virtual machine) where you will run the containers.
(Optional) Take a snapshot: VirtualBox additions installed.