Chapter 3. Prerequisites

Each Ansible Automation Platform node in the cluster must have access to an NTP server. The chronyd is a daemon for synchronization of the system clock. It can synchronize the clock with NTP servers. This ensures that when cluster nodes use SSL certificates that require validation, they don’t fail if the date and time between the nodes are not in sync.

On all the nodes on Environment B including those to be used for the Ansible Automation Platform cluster expansion,

The subscription-manager command registers a system to the Red Hat Network (RHN) and manages the subscription entitlements for a system. The --help option specifies on the command line to query the command for the available options. If the --help option is issued along with a command directive, then options available for the specific command directive are listed.

To use Red Hat Subscription Management for providing packages to a system, the system must first register with the service. In order to register a system, use the subscription-manager command and pass the register command directive. If the --username and --password options are specified, then the command does not prompt for the RHN Network authentication credentials.

An example of registering a system using subscription-manager is shown below.

# subscription-manager register --username [User] --password '[Password]'
The system has been registered with id: abcd1234-ab12-ab12-ab12-481ba8187f60

After a system is registered, it must be attached to an entitlement pool. For the purposes of this reference environment, the Red Hat Ansible Automation Platform is the pool chosen. Identify and subscribe to the Red Hat Ansible Automation Platform entitlement pool, the following command directives are required.

# subscription-manager list --available | grep -A8 "Red Hat Ansible Automation Platform"
---
Subscription Name:   Red Hat Ansible Automation Platform, Premium (5000 Managed Nodes)
Provides:            Red Hat Ansible Engine
                     Red Hat Single Sign-On
                     Red Hat Ansible Automation Platform
SKU:                 MCT3695
Contract:            <contract>
Pool ID:             <pool_id>
Provides Management: No
Available:           9990
Suggested:           1
Service Type:        L1-L3
Roles:

# subscription-manager attach --pool <pool_id>
Successfully attached a subscription for: Red Hat Ansible Automation Platform, Premium (5000 Managed Nodes)

# subscription-manager repos --enable=ansible-automation-platform-2.1-for-rhel-8-x86_64-rpms

Prior to the installation of Ansible Automation Platform 2, it is recommended to create a non-root user with sudo privileges for the deployment process. This user is used for:

For the purposes of this reference environment, the user ansible was chosen, however, any user name would suffice.

On all the nodes on Environment B including those to be used for the Ansible Automation Platform cluster expansion, create a user named ansible and generate an ssh key.

With the ansible user created, as the ansible user, copy the ssh key to all the nodes on Environment B including those to be used for the Ansible Automation Platform cluster expansion. This ensures that when the Ansible Automation Platform installation runs, it can ssh to all the nodes without a password.

This can be done using the ssh-copy-id command as follows:

$ ssh-copy-id ansible@hostname.example.com

Firewall access and restrictions play a critical role in securing Ansible Automation Platform 2 environment. The use of Red Hat Enterprise Linux {rhel_version} defaults to using firewalld, a dynamic firewall daemon. firewalld works by assigning network zones to assign a level of trust to a network and its associated connections and interfaces.

It is recommended that firewall settings be configured to permit access to the appropriate services and ports for a success Ansible Automation Platform 2 installation.

On all the nodes within Environment B including those to be used for the Ansible Automation Platform cluster expansion, ensure that firewalld is installed, started and enabled.