Basics of Ansible

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What is Ansible?

Ansible is a widely-used open-source automation tool designed for configuration management, application deployment, and IT orchestration. It’s a vital component in modern platform engineering, helping teams streamline and automate their infrastructure tasks efficiently.

One of Ansible’s standout advantages is its agentless design, which means it doesn’t require any software to be installed on the remote systems it manages. It also uses simple, human-readable YAML files for configuration, making it accessible even to those new to automation. Additionally, Ansible can handle operations across thousands of machines, making it ideal for scaling environments.

Why Choose Ansible?

  • No Agents Required: Ansible manages remote systems without needing to install any agents, which simplifies both the initial setup and ongoing maintenance.
  • Simple, Readable Syntax: Playbooks in Ansible are written in YAML, making them straightforward to understand and write—even for those new to automation.
  • Cross-Platform Compatibility: Whether you’re working with Linux, Windows, cloud providers, or network gear, Ansible supports a broad range of platforms seamlessly.
  • Highly Scalable: From managing a few servers to orchestrating thousands, Ansible scales effortlessly to suit environments of any size.
  • Rich Collection of Modules and Roles: With an extensive library of built-in modules and reusable roles, Ansible can handle a wide variety of automation tasks with ease.
  • Idempotent by Design: Ansible ensures that running the same playbook multiple times won’t result in unintended changes—once a task is successfully applied, it won’t run again unless needed.

How does Ansible work?

Ansible uses the concepts of control and managed nodes. It connects from the control node, any machine with Ansible installed, to the managed nodes sending commands and instructions to them.

The units of code that Ansible executes on the managed nodes are called modules. Each module is invoked by a task, and an ordered list of tasks together forms a playbook. Users write playbooks with tasks and modules to define the desired state of the system.

The managed machines are represented in a simplistic inventory file that groups all the nodes into different categories.

Ansible leverages a very simple language, YAML, to define playbooks in a human-readable data format that is really easy to understand from day one.

Even more, Ansible doesn’t require the installation of any extra agents on the managed nodes so it’s simple to start using it.

Advantages of Ansible

  • Free to use by everyone.
  • Consistent and lightweight.
  • No constraints regarding OS or underlying hardware.
  • Very secure due to its agentless caps and open-shh security features.
  • Does not need any special system administrator skills to install and use it.
  • Works on Push mechanism- Here the update must be pushed there’s no agent for this purpose.
  • Easy to use as coding here uses YAML scripting.
  • It has a UI-based tool called ansible tower by RedHat.
  • Ansible can be used on-premises as well as on the cloud.
  • Runs on many Unix-like systems and can configure both Unix-like systems as well as Microsoft Windows.

Benefits of using Ansible

  • A free and open-source community project with a huge audience.
  • Battle-tested over many years as the preferred tool of IT wizards.
  • Easy to start and use from day one, without the need for any special coding skills.
  • Simple deployment workflow without any extra agents.
  • Includes some sophisticated features around modularity and reusability that come in handy as users become more proficient.
  • Extensive and comprehensive official documentation that is complemented by a plethora of online material produced by its community.

Basic Concepts & Terms

Here are the key concepts and terms related to Ansible architecture:

  • Host: A remote machine managed by Ansible.
  • Group: Several hosts grouped together that share a common attribute.
  • Inventory: A collection of all the hosts and groups that Ansible manages. Could be a static file in the simple cases or we can pull the inventory from remote sources, such as cloud providers.
  • Modules: Units of code that Ansible sends to the remote nodes for execution.
  • Tasks: Units of action that combine a module and its arguments along with some other parameters.
  • ​​Playbooks: An ordered list of tasks along with its necessary parameters that define a recipe to configure a system.
  • Roles: Redistributable units of organization that allow users to share automation code easier.
  • YAML: A popular and simple data format that is very clean and understandable by humans.

Ansible Workflow

As we discussed above, when services increase, sysadmins will provision more servers to do configuration management. They need not do it manually anymore but install Ansible on the master node where they need to write the code into the Ansible playbook to describe the setup, installation process, and configuration required for these servers.

Once these nodes are connected to the master server, then the node servers are analyzed and the playbook codes are pushed toward each of the servers so that these playbooks can configure the servers remotely, which leads to a consistent environment.

Mahesh Wabale
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