Ansible, a Python-based open-source IT automation tool, operates via the command line. Its capabilities include configuring systems, deploying software, and orchestrating intricate workflows, making it versatile for tasks such as application deployment, system updates, and beyond.
Ansible, a powerful open-source automation tool, stands out for its simplicity, flexibility, and agentless architecture. Ansible scripting allows IT professionals to automate complex tasks, configuration management, and deployment processes with ease.
In this article, we will explore the basics of Ansible scripting, its key components, and how it can be used to simplify and expedite various IT operations.
What is Ansible?
Ansible is defined as an open-source, cross-platform tool for resource provisioning automation that DevOps professionals popularly use for continuous delivery of software code by taking advantage of an “infrastructure as code” approach. Ansible is an automation tool that allows you to define and manage infrastructure as code.
Developed in Python, Ansible uses a declarative language to describe system configurations, making it easy to understand and maintain. One of the key advantages of Ansible is its agentless nature, meaning it doesn’t require any software to be installed on remote systems. Instead, Ansible uses SSH to connect and execute tasks on target machines.
How does Ansible work?
Modules
Ansible works by connecting to nodes (or hosts) and pushing out small programs—called modules—to these nodes. Nodes are the target endpoints—servers, network devices, or any computer—that you aim to manage with Ansible. Modules are used to accomplish automation tasks in Ansible. These programs are written to be resource models of the desired state of the system. Ansible then executes these modules and removes them when finished.
Without modules, you’d have to rely on ad-hoc commands and scripting to accomplish tasks. Ansible contains built-in modules that you can use to automate tasks, or you can write new ones on your own. Ansible modules can be written in any language that can return JSON, such as Ruby, Python, or bash. Windows automation modules can even be written in Powershell.
Agentless automation
Ansible is agentless, which means the nodes it manages do not require any software to be installed on them. Ansible reads information about which machines you want to manage from your inventory. Ansible has a default inventory file, but you can create your own and define which servers you want to be managed.
Ansible uses SSH protocol to connect to servers and run tasks. By default, Ansible uses SSH keys with ssh-agent and connects to remote machines using your current user name. Root logins are not required. You can log in as any user, and then use su or sudo commands as any user.
Once it has connected, Ansible transfers the modules required by your command or Ansible Playbook to the remote machine(s) for execution. Ansible uses human-readable YAML templates so users can program repetitive tasks to happen automatically without having to learn an advanced programming language.
Using Ansible for ad-hoc commands
You can also use Ansible to run ad-hoc commands, which automate a single task on one or more managed nodes. To do this, you will need to run a command or call a module directly from the command line. No playbook is used, and ad-hoc commands are not reusable. This is fine for a one-time task, but anything more frequent or complex will require the use of an Ansible Playbook.
Ansible Playbooks
At the heart of Ansible automation is the playbook. A playbook is a YAML file that defines a set of tasks to be executed on remote hosts. These tasks can include anything from installing software and configuring services to managing files and executing shell commands. Playbooks make it easy to orchestrate complex processes and ensure consistency across multiple systems.
Here’s a simple example of an Ansible playbook (yaml):
---
- name: Install Apache web server
hosts: web_servers
tasks:
- name: Update package cache
apt:
update_cache: yes
- name: Install Apache
apt:
name: apache2
state: present
Inventory
The inventory file is where you define the hosts on which Ansible will execute tasks. It can be a simple text file or a dynamic inventory script that retrieves host information from external sources. By organizing hosts into groups and assigning variables, you can create versatile inventories that cater to various scenarios.
Running Ansible Scripts
Executing Ansible playbooks is a straightforward process. The ansible-playbook command is used to run playbooks against the specified inventory. Ansible will then connect to the remote hosts, execute the defined tasks, and report the results.
ansible-playbook -i inventory.ini my_playbook.yaml
Conclusion
Ansible scripting empowers IT professionals to automate and streamline infrastructure management tasks efficiently. Its simplicity, agentless architecture, and extensive module library make it a popular choice for organizations looking to enhance their automation capabilities. Whether you are managing a small-scale IT environment or a large-scale enterprise infrastructure, Ansible can be a valuable tool in your automation toolkit. As you delve deeper into Ansible scripting, you’ll discover its potential to simplify complex operations and improve the overall efficiency of your IT workflows.
Reference : https://docs.ansible.com/ansible/latest/index.html