Ansible is an open-source IT automation tool that provides an easy way to automate repetitive tasks, deploy applications, and manage infrastructure. With Ansible, you can easily manage and configure systems, whether they are on-premise or in the cloud, without the need for complicated scripts or configuration files. Ansible is built around the concept of “playbooks,” which are YAML files that describe the desired state of the system.

• Core components of Ansible
• Core concepts of Ansible
• Best practices to structure your Ansible inventory
• Playbook best practises
• Installing Ansible
  1. Step 1: Install Python
  2. Step 2: Install Ansible
  3. Step 3: Verify Installation
• Setting Up Ansible Inventory
  1. Step 1: Create Inventory File
  2. Step 2: Test Connection
• Using Ansible Playbooks
  1. Step 1: Create Playbook File
  2. Step 2: Run Playbook
• Ansible Tower
• Installing Ansible Tower
  1. Step 1: Download and Install the Repository
  2. Step 2: Install Ansible Tower
  3. Step 3: Configure Ansible Tower
• Using Ansible Tower
  1. Step 1: Create a Job Template
  2. Step 2: Run the Job Template
  3. Step 3: Monitor the Job
• Conclusion

In this guide, we’ll cover the basics of how to implement Ansible, including installing Ansible and setting up Ansible Tower. We’ll also discuss how to use Ansible playbooks to automate tasks, configure systems, and deploy applications.

Core components of Ansible

The core components of Ansible are as follows:

• Inventory: The inventory is a list of hosts or nodes that Ansible can connect to and manage. It contains information about the target hosts such as hostname, IP address, and connection credentials. The inventory can be stored in various formats such as YAML, JSON, and INI.
• Playbooks: Playbooks are YAML files that define the desired state of the system. They contain a list of tasks to be executed on the target hosts, in order to achieve a specific configuration or deployment goal. Playbooks are the heart of Ansible and enable users to automate complex tasks with ease.
• Modules: Ansible modules are reusable scripts that are executed on the target hosts. They are responsible for carrying out specific tasks, such as installing a package or copying a file. Modules are stored on the control node and are executed remotely on the target nodes.
• Roles: Roles are a way to organize playbooks and make them reusable. They allow users to break down complex playbooks into smaller, more manageable parts. Roles are essentially a collection of tasks, files, templates, and variables, all packaged together into a single directory structure.
• Variables: Ansible variables are used to store values that can be used throughout a playbook or role. They can be defined in various places, such as in the inventory, in a playbook, or in a role. Variables can be used to make playbooks more flexible and configurable.
• Templates: Templates are files that contain dynamic content and can be customized for different target hosts. They are typically used to generate configuration files or scripts. Templates use Jinja2 syntax, which allows for dynamic variable substitution and control structures.
• Handlers: Handlers are tasks that are only executed when notified by another task. They are typically used for service restarts or other actions that need to be triggered after a specific task has completed.

These core components work together to provide a powerful and flexible automation framework that can simplify infrastructure management and application deployment.

Core concepts of Ansible

The following are some key concepts of Ansible:

• Control node: The control node is the machine from which Ansible is run. It contains the Ansible command-line tools and playbooks that define the desired state of the infrastructure. The control node communicates with the target hosts to execute tasks and manage their configuration.
• Target host: The target host is the machine or device that Ansible manages. Ansible communicates with the target host over SSH or WinRM to execute tasks and manage its configuration.
• Inventory: The inventory is a list of target hosts that Ansible manages. It contains information about the target hosts, such as their hostname, IP address, and connection credentials. The inventory can be stored in various formats, such as YAML, JSON, and INI.
• Playbook: A playbook is a YAML file that defines a set of tasks to be executed on the target hosts. Playbooks can be used for configuration management, application deployment, and IT orchestration. Playbooks are executed sequentially, and Ansible ensures that the desired state is achieved on each target host.
• Task: A task is a single action that is executed on a target host. Tasks can be used to manage files, install packages, restart services, and perform other actions that configure or manage the infrastructure.
• Module: A module is a reusable script that is executed on the target host to perform a specific task. Ansible comes with many built-in modules that can be used for common tasks, such as managing files, installing packages, and restarting services. Custom modules can also be created to perform specific tasks.
• Role: A role is a collection of tasks, files, templates, and variables that can be reused across different playbooks. Roles are a way to organize playbooks and make them more modular and reusable.
• Variable: A variable is a value that is used to define properties of a target host or to pass information between tasks. Variables can be defined in the inventory, in a playbook, or in a role.
• Template: A template is a file that is used to generate dynamic content, such as configuration files. Templates use the Jinja2 syntax, which allows for dynamic variable substitution and control structures.
• Facts: Facts are system properties and metadata that are collected from target hosts by Ansible. They can be used to conditionally execute tasks, or to pass information between tasks.

By understanding these key concepts, users can effectively use Ansible to manage their infrastructure and automate their IT operations.

Best practices to structure your Ansible inventory

Ansible Inventory is the source of truth for the infrastructure managed by Ansible. It is essential to structure the inventory in a well-organized manner, which makes it easy to manage and maintain. Here are some best practices to structure Ansible Inventory:

1. Use a directory structure: The inventory can be structured using a directory structure that reflects the organizational structure of the environment. For example, the inventory directory could have subdirectories for different regions, data centers, or environments.
2. Use group names: Group names are a way to logically group hosts. They can be used to represent different tiers of an application, such as web servers, application servers, or database servers. Group names can also represent different regions, environments, or business units.
3. Use aliases: Aliases are alternative names for hosts that make it easier to refer to them in playbooks. Aliases can be used to refer to hosts in different groups or to group hosts with similar characteristics.
4. Use variables: Variables can be used to define host-specific or group-specific properties. For example, a variable could be used to define the SSH port for a particular host, or to define the version of a software package that should be installed on a group of hosts.
5. Use dynamic inventory: Ansible supports dynamic inventory, which means that the inventory can be generated programmatically. This is useful for environments where hosts are created and destroyed frequently, such as cloud environments.
6. Document the inventory: It is important to document the inventory so that it is clear what each group represents and what variables are used. This can be done using comments in the inventory file or by maintaining a separate documentation file.

By following these best practices, the Ansible inventory can be structured in a way that is easy to manage, maintain, and extend.

Playbook best practises

Playbooks are a key component of Ansible, and they provide a way to define and execute complex automation workflows. Here are some best practices for writing effective and maintainable Ansible playbooks:

• Use a modular approach: Playbooks can become large and complex, so it’s important to break them down into smaller, reusable components. This can be achieved by using roles, which are reusable units of work that can be shared across playbooks.
• Use comments: Use comments to explain the purpose of each task or play in the playbook. This can be especially helpful for other team members who may need to modify the playbook in the future.
• Use YAML syntax: Ansible playbooks are written in YAML, a human-readable data serialization format. It’s important to adhere to the YAML syntax rules to ensure that the playbook can be parsed correctly.
• Use variables: Use variables to parameterize the playbook, making it more flexible and easier to reuse. Variables can be defined at various levels, such as the inventory, playbook, or role level.
• Use conditionals: Use conditionals to control the flow of the playbook based on specific criteria, such as the target host, the operating system, or the value of a variable.
• Use idempotent tasks: Ansible is designed to be idempotent, meaning that it should be safe to run a playbook multiple times without causing unintended side effects. Use idempotent tasks to ensure that the playbook behaves predictably and consistently.
• Use error handling: Use error handling to handle failures and unexpected events during the playbook execution. This can be achieved by using try/catch blocks or the fail module.
• Use tags: Use tags to selectively run specific tasks or plays in the playbook. This can be helpful for debugging, testing, or when making incremental changes to the playbook.
• Test the playbook: Test the playbook thoroughly before deploying it to production. This can be achieved by running the playbook in a test environment, using the –check flag to perform a dry-run, or by using a continuous integration tool to automate testing.

By following these best practices, users can create maintainable, flexible, and reusable Ansible playbooks that can be used to automate their IT operations.

Installing Ansible

Before you can start using Ansible, you’ll need to install it on your system. Ansible can be installed on a variety of platforms, including Linux, macOS, and Windows. In this guide, we’ll focus on installing Ansible on a Linux-based system.

Step 1: Install Python

Ansible requires Python to be installed on the system. Most Linux distributions come with Python pre-installed, but you can check to make sure by running the following command:

$ python --version

If Python is not installed, you can install it using the package manager for your distribution. For example, on Ubuntu, you can run the following command to install Python:

$ sudo apt-get install python

Step 2: Install Ansible

Once Python is installed, you can install Ansible. Ansible can be installed using the package manager for your distribution. For example, on Ubuntu, you can run the following command to install Ansible:

$ sudo apt-get install ansible

Step 3: Verify Installation

Once Ansible is installed, you can verify the installation by running the following command:

$ ansible --version

This should display the version of Ansible that was installed.

Setting Up Ansible Inventory

Before you can start using Ansible to manage your infrastructure, you’ll need to create an inventory file. The inventory file is a YAML file that lists the hosts that Ansible will manage.

Step 1: Create Inventory File

To create an inventory file, create a new file in the following directory:

/etc/ansible/hosts

The file should have the following format:

[web]
192.168.1.100
192.168.1.101

[db]
192.168.1.102

In this example, we’ve created two groups, “web” and “db”, and listed the hosts that are part of each group. You can replace the IP addresses with the IP addresses of the hosts you want to manage.

Step 2: Test Connection

Once you’ve created the inventory file, you can test the connection to the hosts by running the following command:

$ ansible all -m ping

This will ping all of the hosts in the inventory file and verify that Ansible can connect to them.

Using Ansible Playbooks

Now that you have Ansible installed and your inventory file set up, you can start using Ansible playbooks to automate tasks.

Ansible playbooks are YAML files that describe the desired state of the system. Playbooks consist of one or more “plays,” which are a set of tasks to be performed on a group of hosts.

Step 1: Create Playbook File

To create a playbook, create a new YAML file in a directory of your choosing. The file should have the following format:

---
- name: Playbook Name
  hosts: web
  tasks:
    - name: Task Name
      apt:
        name: nginx
        state: present

In this example, we’ve created a playbook that installs the Nginx web server on the hosts in the “web” group.

The “name” field is a human-readable name for the playbook, while the “hosts” field specifies the group of hosts that the playbook will run on. The “tasks” field contains a list of tasks to be performed on the hosts.

In this example, we’ve created a single task that installs Nginx using the “apt” module. The “name” field in the task is a human-readable name for the task, while the “apt” module is responsible for installing packages on Ubuntu-based systems.

Step 2: Run Playbook

To run the playbook, use the following command:

$ ansible-playbook playbook.yml

This will run the playbook and install Nginx on the hosts in the “web” group.

Ansible Tower

Ansible Tower is a web-based UI and API for Ansible. Ansible Tower provides a centralized interface for managing and executing Ansible playbooks, as well as monitoring and tracking their execution.

Installing Ansible Tower

To install Ansible Tower, follow these steps:

Step 1: Download and Install the Repository

Download and install the Ansible Tower repository by running the following command:

$ sudo yum install -y https://releases.ansible.com/ansible-tower/setup/ansible-tower-repo-latest.el7.noarch.rpm

Step 2: Install Ansible Tower

Install Ansible Tower by running the following command:

$ sudo yum install ansible-tower

Step 3: Configure Ansible Tower

After installing Ansible Tower, you’ll need to configure it by running the following command:

$ sudo /usr/bin/tower-cli setup

This will prompt you to enter the necessary configuration details, such as the database type and credentials.

Using Ansible Tower

Once Ansible Tower is installed and configured, you can start using it to manage and execute your Ansible playbooks.

Step 1: Create a Job Template

To create a job template, navigate to the “Templates” page in the Ansible Tower UI and click the “Add” button. In the “Add Job Template” dialog, enter the necessary details, such as the name, inventory, and playbook.

Step 2: Run the Job Template

Once the job template is created, you can run it by clicking the “Launch” button. This will launch a job that executes the playbook on the hosts specified in the inventory.

Step 3: Monitor the Job

You can monitor the job’s progress by navigating to the “Jobs” page in the Ansible Tower UI. Here, you can view the status of the job, including any errors or warnings.

Conclusion

In this guide, we’ve covered the basics of how to implement Ansible, including installing Ansible and setting up Ansible Tower. We’ve also discussed how to use Ansible playbooks to automate tasks, configure systems, and deploy applications.

By leveraging Ansible, you can significantly reduce the amount of time and effort required to manage and configure your infrastructure, freeing up valuable resources to focus on more critical tasks. Additionally, Ansible Tower provides a centralized interface for managing and executing your Ansible playbooks, simplifying the management of your infrastructure even further.