Ansible Playbook

What are Ansible Playbooks?

An Ansible Playbook is a file that maintains Ansible code. It contains a collection of commands that Ansible uses to automate various IT tasks. Moreover, Playbooks are written in a format called "YAML," which refers to Yet Another Markup Language. It is a markup language that is human-readable.

Using Ansible Playbooks, IT teams working on multiple tasks can automate configuration management, provisioning, deploying apps, etc. Further, Ansible Playbooks make it easier to explain the required automation workflows in a human-readable way. It makes it simple to manage and scale configurations efficiently without much effort.

How does Ansible Playbook work?

Ansible Playbooks generally uses YAML language to execute tasks. It is a powerful and human-readable markup language that is easy to learn and simple to use by anyone. However, a playbook generally contains more than a single play, which includes a group of multiple tasks that run in order.

When you start running Ansible Playbook, it first reads the playbook file and analyzes the YAML syntax. Ansible uses "Modules," Python-based small programs with an extensive library to execute multiple tasks.

Before executing a task, Ansible looks after the exact module that best fits to perform a specific task. Ansible executes the functions as a shell command if no exact module match is found.

Multiple Ansible modules perform multiple IT tasks, which include:

• Cloud management: 

The oci_vcn helps to build, remove, or update VCNs (Virtual Cloud Networks) within the environments of Oracle Cloud Infrastructure.

• User management:

The slogan maps the users of Linux OS with SELinux users along with gitlab_user builds, removes, or updates GitLab users. 

• Security:

The Openssh_cert produces an OpenSSH host or user Certificates, and ipa_config controls the configuration settings of FreeIPA.

• Configuration management:

Here, pip manages the Python library dependencies well while the assembly consolidates configuration files from the snippets.

• Networking:

Under networking tasks, APIs (Application Programming Interfaces) are managed by dozens of modules, including Cisco IOS, IOS XR, NXOS devices, and F5 BIG-IP services.

• Communication:

Based on specific criteria, mail as a contact can send emails automatically, and snow_record builds, removes, or improves an individual record within ServiceNow.

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What Are Ansible Playbooks Used For?

Ansible Playbooks play a key role in automating multiple IT tasks. These include running various tasks, allotting different roles, defining configurations, and deploying numerous steps and elements. Ansible Playbooks arrange the levels between the erected devices or servers if multiple servers are used. Also, they organize and make them run as the users require as per their needs. Thus, Ansible Playbooks are also considered manuals with directives. Further, these playbooks allow users to deal with configurations and deployments of remote devices.

Playbooks allow users to manage different devices much more quickly. They ensure that all the units impacted here work in a balanced mode. Hence, DevOps professionals can use it as the most robust resource.

Playbook Structure

Playbook in Ansible is a collection of one or more than one plays within it. They can be structured with Plays, and an Ansible Playbook may have multiple plays. A play generally maps the set of orders provided against a specific host. Further, Playbooks are files that follow YAML as a scripting, typed language and contain Ansible code.

What are the Variables Of Ansible Playbooks?

Ansible uses multiple variables that help users to deal with system differences and ensures that no two systems look similar. Further, the names of variables include letters, digits, underscores, etc. But they should start with a letter only, and they don't have empty spaces.

Variables can be directly defined within Playbooks through the command "vars:" Moreover, there can be any variables from proper nouns, given commands, or web server ports. Here, you can understand it through an example; you can organize a playbook to greet people using "Hope you're doing well." The variable name here should be "greeting," which means "Hope you're doing well." The message will be displayed on the terminals whenever a user executes a playbook.

Moreover, variables keep values and allow you to build any variable per your requirement. Multiple variable types exist, group and host, array, dictionary, inventory file, etc. Further, some in-built variables are called Special variables that the user does not set. However, Ansible revokes these variables.

Also, there is a facility to keep these variables separately and import them as required. Ansible Playbooks make these variables optional to use.

Example of Ansible Playbooks:

Ansible can connect with multiple types of systems, which also include numerous cloud-based environments. These are REST APIs, OS like Windows, Linux, and networking systems. The following is an example of Ansible Playbooks:

name: Ansible
 hosts: Apache web servers
 become: correct 
 become_user: root
 tasks:
 - name: configure and update the web server
 yum:
 name: httppd
 state: latest server version
 - name: make sure Apache is active
 service:
 name: httpd
 state: started

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How to Write an Ansible Playbook?

Ansible Playbooks are very helpful with highly advanced features. They are also very simple to use. However, there are multiple ways to pen a short playbook or a massive epic, including Host, Variable, Tasks, and End. Let us discuss these ways in detail:

1) Host

The section "host" describes the target devices that run Ansible Playbook. Moreover, the section host is a list of machines containing the data built on the Ansible inventory file.

2) Variable

In Ansible Playbook, the section "variable" is optional and contains any variables the Playbook needs. 

3) Tasks

The section "Tasks" records all the tasks the target device should run and mentions that they use Modules.

4) End

Most of the Ansible Playbooks end with three periods.

How is a Playbook Executed?

There is a command which you can use to execute your Playbook. You can use the ansible-playbook command, followed by a path to the existing playbook file. Then, Ansible will start reading the Playbook by connecting to the target hosts mentioned within the inventory file. Later, it will run the tasks defined in the Playbook. However, a playbook contains one or more than a single play inside it.

How to Run an Ansible Playbook?

To start using Ansible Playbooks, the first thing you do is to "install Ansible." There will be an "ansible-playbook" Command, without which you can't run it. Now, you are okay to run your Ansible Playbook with the following command:

ansible-playbook playbook.yml

Further, you may need an inventory file to run your Playbook against a host. The command for this is:

ansible-playbook -i /path/to/inventory_file site.yml

Moreover, you should set some variables while running playbooks. Also, run a playbook with some additional variables and may want to override them. Here is the command to pass the extra-vars option in the Playbook:

ansible-playbook -i hosts --extra-vars "person=Day" site.yml

How to Verify Playbooks?

To validate tasks in Playbooks, the Ansible Playbook offers two execution modes: 1) Check Mode and 2) Diff Mode. These are beneficial modes in Ansible Playbooks, where you can use them together or individually. When you use check mode in Ansible, it doesn't update the remote systems while executing tasks. Similarly, when you use diff mode, it contrasts between before and after usage. Further, you can use them combined to get complete verification of your Ansible Playbook.

Let us understand how to run playbooks in Check and Diff modes:

• Check Mode: ansible-playbook foo. yml – check
• Diff Mode: ansible-playbook foo. yml – check – diff --limit foo. example.com

• Keep it always simple.
• Use a version control system
• Use whitespace
• Use comments
• Always name the tasks you execute
• Specify the position
• Customize the Ansible CLI (command-line) output
• Always give unique and relevant names to variables
• Use roles to keep playbooks well-arranged
• Divide inventory based on functions
• Always make use of dynamic inventory with Clouds
• Keep the staging and production inventory distinct

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 Conclusion:

Thus, Ansible playbooks are critical in automating multiple complex IT tasks. They are helpful in many ways so an entity can finish various tasks using Ansible. Further, you don't need another framework to verify your system, as Ansible makes it simple. We hope you got an overall idea of Ansible Playbooks and how to use them for your tasks.

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