How To Install Ansible on CentOS Stream 10

In this tutorial, we will show you how to install Ansible on CentOS Stream 10. In today’s fast-paced IT environment, automation is key to maintaining efficiency and consistency across servers and applications. Ansible, a powerful open-source automation tool, simplifies the process of managing complex IT infrastructures. This guide will walk you through the step-by-step process of installing Ansible on CentOS Stream 10, ensuring that you have everything you need to get started with automation.

Understanding Ansible

Ansible is an agentless automation tool that enables system administrators to automate tasks such as configuration management, application deployment, and orchestration. Unlike other automation tools like Chef and Puppet, Ansible operates over SSH without requiring any agent installation on the managed nodes. This makes it lightweight and easy to use.

Some common use cases for Ansible include:

• Automating server provisioning
• Managing configuration files
• Deploying applications across multiple servers
• Orchestrating complex workflows

Prerequisites for Installation

Before installing Ansible, ensure that your system meets the following prerequisites:

• A running instance of CentOS Stream 10.
• Root or sudo access to the system.
• An active internet connection to download packages.

It is also advisable to have a basic understanding of Linux command-line operations.

Updating Your System

Keeping your system up-to-date is crucial for stability and security. Before installing any new software, execute the following command to update your system:

sudo dnf update -y

This command ensures that all existing packages are updated to their latest versions, reducing the risk of conflicts during installation.

Installing the EPEL Repository

Ansible is not available in the default CentOS repositories; thus, you need to enable the Extra Packages for Enterprise Linux (EPEL) repository. EPEL provides a wide array of additional packages that enhance the functionality of CentOS systems.

Step 1: Enable the CRB Repository

The CodeReady Builder (CRB) repository must be enabled before installing EPEL. Use the following command:

sudo dnf config-manager --set-enabled crb

Step 2: Install EPEL Repository

Run this command to install the EPEL repository:

sudo dnf install epel-release -y

This command installs the EPEL release package, allowing access to additional software repositories. Verify that EPEL has been successfully enabled by checking the repository list:

sudo dnf repolist

Installing Ansible

With the EPEL repository enabled, you can now install Ansible using the following command:

sudo dnf install ansible -y

This command downloads and installs Ansible along with its dependencies. Once installed, verify the installation by checking the version:

ansible --version

You should see output indicating the installed version of Ansible, confirming a successful installation.

Configuring SSH Access

Ansible communicates with managed nodes over SSH. Therefore, it is essential to configure SSH access for seamless communication between your control node (where Ansible is installed) and managed nodes.

Step 1: Generating SSH Keys

If you do not already have an SSH key pair, generate one using the following command:

ssh-keygen -t rsa -b 2048

This command generates a new RSA key pair with a length of 2048 bits. You can press Enter to accept the default file location and passphrase when prompted.

Step 2: Copying SSH Keys to Managed Nodes

To allow Ansible to connect to your managed nodes without needing a password each time, copy your public key to each managed node using:

ssh-copy-id user@remote-server

Replace user@remote-server with your actual username and hostname or IP address of the managed node. This command will prompt you for your password on the remote server one last time.

Setting Up the Inventory File

The inventory file is where you define which hosts Ansible will manage. By default, this file is located at /etc/ansible/hosts.

Step 1: Creating an Inventory File

Edit the inventory file using a text editor such as vi:

sudo vi /etc/ansible/hosts

Step 2: Sample Inventory Configuration

Add your managed nodes in this format:

[webservers]
server1
server2

[databases]
db1
db2

This configuration defines two groups: [webservers], which includes server1, and [databases], which includes db1.

Testing the Installation

Step 1: Using the Ping Module

The best way to test if your installation was successful and if Ansible can communicate with your managed nodes is by using the ping module:

ansible all -m ping

This command tells Ansible to ping all hosts defined in your inventory file. If everything is configured correctly, you should receive a response indicating success from each host.

Troubleshooting Tips:

• If you encounter issues with connectivity, ensure that SSH is running on your managed nodes and that they are reachable over the network.
• If you receive errors related to permissions or authentication, double-check that your SSH keys are correctly set up.
• You can also increase verbosity by adding -vvv at the end of your ping command for more detailed output:

  ansible all -m ping -vvv 

Create a Simple Playbook

A playbook in Ansible defines a series of tasks that will be executed on specified hosts. Playbooks are written in YAML format and are essential for automating complex tasks.

Create Your First Playbook

To create a simple playbook that installs Nginx on all web servers defined in your inventory file, follow these steps:

1. Create a new YAML file for your playbook:

sudo vi /etc/ansible/install-nginx.yml 

2. Add the following content to define your playbook:

- hosts: webservers
  become: yes
  tasks:
    - name: Install Nginx
      yum:
        name: nginx
        state: present
      notify:
        - start nginx

  handlers:
    - name: start nginx
      service:
        name: nginx
        state: started
        enabled: yes
      

3. This playbook does three things:
   • Selects hosts from the group [webservers].
   • Uses sudoness (become), which allows tasks to run with elevated privileges.
   • Adds a task to install Nginx using yum package manager and ensures it starts automatically at boot.
   • The handler starts Nginx after installation if it was changed during execution.
   • You can save and exit by pressing ESC followed by typing :wq!
   • The next step is running this playbook on your defined hosts.

Running Your Playbook

To execute your newly created playbook, use this command:

ansible-playbook /etc/ansible/install-nginx.yml 

This command will run all tasks defined in your playbook against all hosts specified in the inventory file under [webservers]. You should see output indicating whether each task was successful.

Troubleshooting Playbook Execution:

• If you encounter errors while running your playbook, check for syntax errors in your YAML file. YAML is sensitive to indentation; ensure proper spacing.
• If a task fails during execution, review its output for clues about what went wrong. Common issues include missing packages or incorrect module names.
• You can also use verbosity flags (-vvv ) when running ansible-playbook for more detailed output about what happens during execution:

ansible-playbook /etc/ansible/install-nginx.yml -vvv 

Congratulations! You have successfully installed Ansible. Thanks for using this tutorial to install the latest version of the Ansible Simple IT Automation on CentOS Stream 10. For additional help or useful information, we recommend you check the official Ansible website.