Gain insights into Ansible's core features like inventory, playbooks, and roles. Delve into writing playbooks, using Jinja2, and organize tasks for efficient, stable IT infrastructure management.

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Configuration management plays a pivotal role in maintaining a stable and organized IT infrastructure by enabling the systematic gathering of information from remote hosts, facilitating server provisioning, and streamlining application upgrades or deployments.

You will learn the core features of Ansible, such as inventory, variables, playbooks, roles, and handlers, which serve as the building blocks for configuration management. You will learn how to write playbooks that define and execute complex orchestration tasks with ease. Next, you’ll learn how to use roles to maintain consistency across configuration management projects and how to harness the power of Jinja2 to apply logic and control structures and generate configuration files dynamically.

After completing this course, you will be equipped with the necessary skills for customizing configurations, organizing automation tasks efficiently, and maintaining a desired state for your infrastructure.

Configuration Management Using Ansible

# Overview
Configuration management is critical for managing our infrastructure setup efficiently. With configuration management, we can easily keep track of the changes through the version control system. Keeping up with our growing IT infrastructure or maintaining reliability with configuration management becomes easier.

As depicted in the illustration above, configuration management helps to perform the following tasks:

- **Adjust the configuration of remote servers:** We can update the version of a particular software package using a configuration management tool like Ansible.
- **Provision virtual machines**: We can create a new virtual machine using Ansible with the necessary components like storage and networking provisioned together.
- **Configure databases:** We can manage database systems like PostgreSQL, MySQL, and even caching solutions like Redis using the available modules.
- **Deploy application code:** We can use a configuration management solution for continuous deployment. For example, we can drop the artifacts after a build process completes on Jenkins using Ansible.
 
# Idempotency
Idempotency is an important concept where changing system configuration is concerned. The term **idempotent** means that after we perform an action for the first time, performing the same action in the future should not cause any change to the system. 

## Advantages of idempotency

Here are some of the advantages that idempotency provides:

- We save system resources by not repeatedly running an already executed task again.
- We avoid altering the configuration files or packages. For instance, a new version of a package can get installed, overwrite the previous version, and cause an issue with a running process that depends on such a package.

## How idempotency works
Let's say we have a task that requires us to install NGINX without any change to the NGINX package when we try to install it the second time. We don't want any change to the already installed NGINX package unless we want to make deliberate changes to the package version. This is because changing the state of this package can cause the web pages we're already serving to be unavailable, as well as cause the overall unavailability of our web pages/services. Here's how we can complete our task successfully: 

1. We'll run the playbook to install NGINX using either of the commands below:
   ```s
   ansible-playbook -D nginx.yml
   ```
   ```s
   ansible-playbook nginx.yml
   ```
2. We'll run the command multiple times and confirm that there are no changes to the NGINX packages after the first attempt at installation.

Discover how idempotency works in Ansible.

Getting Started

What Is Configuration Management?

Basics of Ansible

Major Concepts in Ansible

Ansible Variables and Other Elements

Manage Configuration with Ansible

Wrap Up

Deploy a Web Application Using Ansible

The Concept of Idempotency in Ansible

Overview