If you're reading this, it means your application has reached a stage of success after going through an extensive development and deployment process. Your application has grown to a point where manually managing servers is no longer feasible, and you need to deploy them rapidly. Additionally, you must ensure that your application has the same configuration, packages, and versions on all servers. This is where Infrastructure as Code (IaC) comes into play, and Ansible is a crucial tool for implementing it.

In this article, I'll introduce you to Ansible, a tool you can use to define your infrastructure as code before diving into Ansible, let's first define what IaC is, how it works, and how you can use it to streamline your infrastructure management, including integration with monitoring tools like Sensu.

What is Infrastructure as Code (IaC)?
We live in an era of automation where almost with a single click, we can bring an entire server into a functional state. This server may include your favorite operating system, your applications, security rules, disk space, and countless custom configurations. Server configuration can now be replicated dozens, hundreds, or even thousands of times without human intervention. This is where Infrastructure as Code (IaC) comes into play.

IaC is a process where you define a configuration script that contains all the necessary settings and customizations, and a provisioning tool takes care of the rest, automatically. Now, let's delve into the tools that assist you in defining your infrastructure as code, starting with Ansible.

What is Ansible?
In simple terms, Ansible is a tool that helps you automate tasks to achieve a desired state on a system. A task can be as simple as defining the installation of a package, configuring web server settings, or even setting up an entire deployment infrastructure.

Installing Ansible
Installing Ansible is straightforward, and the preferred method is to use the package manager that comes with your Linux distribution. For example, if you're using RHEL or CentOS, you can simply run the following command:
$ sudo yum install ansible
This command will install Ansible along with its dependencies. You can also install Ansible from its source or using pip (Python package manager).

Key Concepts in Ansible
Before you start working with Ansible, there are four key concepts you should be aware of:

Ansible Tasks: These are the actions Ansible will perform.
Ansible Inventory: A list of the host machines where Ansible will execute tasks.
Ansible Play: Maps the groups of host machines defined in the inventory to the tasks that will be carried out.
Ansible Playbook: A file containing all the plays that Ansible will perform on the inventory. It defines the desired state of the system.
The most common way to use Ansible is in "push" mode. In this mode, Ansible connects to each host listed in the inventory file and executes all the plays defined in the playbook. There's no need for agents or other software running on the target hosts. Ansible will connect to them using SSH, although that's not the only way.

Ansible tasks are designed to be idempotent, which means running tasks repeatedly doesn't cause additional changes. This allows you to safely run Ansible playbooks multiple times during automation expansion and even re-run the entire playbook if some tasks fail.

A simple Ansible inventory file might look like this:
192.168.1.23
[db]
10.2.14.23
[webservers]
server1.domain.com
server2.domain.org

As you can see, it's simply a list of IP addresses and full domain names. However, it can also include ranges or custom scripts as needed. The text enclosed in square brackets defines a group of hosts. When a playbook specifies a group, Ansible will interact only with the hosts within that group.

Creating Your First Ansible Playbook
Now that we have Ansible installed, let's start by creating a simple Ansible playbook. This is where you'll begin to see the power of automation and how it can enhance your application development and deployment workflows. Here's an example Ansible playbook:
`---

• hosts: webservers remote_user: yourname tasks:
  • name: Install nginx become: yes become_method: sudo apt: name: nginx state: latest ` This playbook defines tasks to be applied to hosts within the "webservers" group. This playbook does the following:

Connects to the hosts in the "webservers" group and installs the "nginx" package, ensuring it's the latest version.
To run an Ansible playbook, you can use the following command:

$ ansible-playbook playbook.yml

This command executes the playbook and performs the specified tasks on the target hosts.

This is a basic example to help you understand how Ansible works. Ansible can automate more complex scenarios, allowing you to manage your infrastructure more efficiently.

Advanced Ansible Scenarios
As you become more comfortable with Ansible, you can tackle advanced scenarios. For instance, you can explore open-source monitoring and observability solutions like Sensu.

At this point, I hope you've seen the power of automation and how it can improve your workflows in application development and deployment. Now, it's time to get to work.