Chapters
Ansible for Configuration Management: Automating Infrastructure the Smart Way
✅ Chapter 3: Writing and Executing Ansible Playbooks
🔍 Introduction
Now that you have installed Ansible and configured your
environment, it’s time to start writing Playbooks — the real power of
Ansible!
In this chapter, you’ll learn:
- What
Playbooks are and how they are structured
- Writing
your first simple Playbook
- Using
tasks, variables, handlers, loops, and templates
- Structuring
Playbooks efficiently with roles
- Executing
Playbooks and understanding outputs
- Best
practices for writing clean, efficient, and reusable Playbooks
By the end, you’ll be able to create production-ready
automation scripts with Ansible!
🛠️ Part 1: What is a
Playbook?
An Ansible Playbook is a YAML file that
describes:
- The hosts
to target
- The tasks
to perform
- The order
in which actions should happen
- Conditions,
loops, and handlers for advanced logic
Instead of running ad-hoc commands manually, Playbooks
automate complex, multi-step operations in a reliable, repeatable way.
A Playbook is your automation recipe!
📋 Basic Structure of a
Playbook
yaml
CopyEdit
---
-
name: Configure web servers
hosts: webservers
become: yes
tasks:
- name: Install Apache
apt:
name: apache2
state: present
- name: Start Apache service
service:
name: apache2
state: started
✅ Human-readable and easily
extendable!
🔹 Key Components of a
Playbook
|
Component |
Purpose |
|
name |
Description of the
play or task |
|
hosts |
Target group
of hosts |
|
become |
Privilege escalation
(sudo) |
|
tasks |
List of actions
to perform |
|
vars |
Variables for reuse |
|
handlers |
Special tasks
triggered on changes |
|
roles |
Reusable, organized
sets of Playbooks and tasks |
🏗️ Part 2: Writing Your
First Playbook
Let’s build a simple Playbook to install and start Apache
web server.
📋 Example: Install Apache
install_apache.yml
yaml
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---
-
name: Install and start Apache webserver
hosts: webservers
become: yes
tasks:
- name: Install Apache
apt:
name: apache2
state: present
update_cache: yes
- name: Ensure Apache is running
service:
name: apache2
state: started
✅ Save the file and run:
bash
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ansible-playbook
-i inventory.ini install_apache.yml
📚 Part 3: Advanced Task
Features
Tasks can become powerful with variables, conditionals,
loops, and handlers.
🔹 Using Variables
Variables make Playbooks flexible and DRY (Don't Repeat
Yourself).
Example:
yaml
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vars:
http_port: 80
tasks:
- name: Open firewall for HTTP
ufw:
rule: allow
port: "{{ http_port }}"
proto: tcp
✅ Easy to update across the
Playbook.
🔹 Using Conditionals
(when)
Execute tasks only if certain conditions are met.
yaml
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tasks:
- name: Install Nginx only on Ubuntu
apt:
name: nginx
state: present
when: ansible_distribution ==
"Ubuntu"
🔹 Using Loops
Repeat actions easily without repeating code.
yaml
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tasks:
- name: Install multiple packages
apt:
name: "{{ item }}"
state: present
loop:
- git
- curl
- vim
✅ Loops make tasks compact!
🔹 Using Handlers
Handlers are triggered only when notified by tasks.
yaml
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tasks:
- name: Update web content
copy:
src: index.html
dest: /var/www/html/index.html
notify: Restart Apache
handlers:
- name: Restart Apache
service:
name: apache2
state: restarted
⚙️ Part 4: Templates with Jinja2
Templates allow dynamic file generation based on variables.
📋 Example: Using a
Template
templates/index.html.j2
html
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<html>
<head><title>{{ site_name
}}</title></head>
<body>Welcome to {{ site_name
}}!</body>
</html>
Task to deploy:
yaml
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tasks:
- name: Deploy customized index page
template:
src: templates/index.html.j2
dest: /var/www/html/index.html
Variables (site_name) can be defined in the Playbook!
🧩 Part 5: Organizing
Playbooks with Roles
As Playbooks grow, you must modularize using roles.
Roles structure:
bash
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roles/
webserver/
tasks/
main.yml
templates/
files/
vars/
handlers/
✅ Roles make projects scalable,
reusable, and cleaner.
📋 Example: Assigning a
Role
yaml
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-
hosts: webservers
roles:
- webserver
📦 Part 6: Running and
Debugging Playbooks
Run Playbooks:
bash
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ansible-playbook
-i inventory.ini playbook.yml
🔹 Useful Playbook Run
Options
|
Option |
Purpose |
|
--check |
Dry-run (no changes
made) |
|
--diff |
Show
differences |
|
-v, -vv, -vvv |
Increase verbosity |
|
--limit "host_group" |
Target
specific hosts |
|
--start-at-task
"task name" |
Resume from a failed
task |
📋 Example: Dry Run
Playbook
bash
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ansible-playbook
-i inventory.ini install_apache.yml --check
✅ See what would change without
making changes.
📈 Best Practices for
Writing Playbooks
|
Best Practice |
Why Important |
|
Use clear names for
tasks |
Easier to debug |
|
Reuse code with roles and templates |
Scalable |
|
Group related tasks
into plays |
Logical structure |
|
Keep tasks idempotent |
Reliable
re-runs |
|
Use variables for
configuration |
Flexible and clean |
|
Separate sensitive data |
Use Ansible
Vault |
🌍 Real-World Playbook Use
Cases
- Setting
up LAMP or MEAN stack servers
- Deploying
Docker containers and Kubernetes clusters
- Provisioning
cloud infrastructure (AWS, Azure)
- Configuring
load balancers and firewalls
- Patching
Linux servers automatically
- Enforcing
security baselines across VMs
🚀 Summary: What You
Learned in Chapter 3
- What
Playbooks are and their basic structure
- How
to write and run your first Playbook
- Using
variables, loops, conditionals, and handlers
- Creating
dynamic templates with Jinja2
- Organizing
large Playbooks with roles
- Best
practices for clean, scalable automation
Playbooks are the heart of Ansible — master them and you can automate almost anything!
BackFAQs
❓1. What is Ansible and how is it used in configuration management?
Answer:
Ansible is an open-source automation tool used for configuration management,
application deployment, and orchestration. It helps automate the process of
setting up and maintaining systems in a desired state without manual
intervention, using simple YAML-based playbooks over SSH connections.
❓2. How is Ansible different from other configuration management tools like Puppet or Chef?
Answer:
Unlike Puppet or Chef, Ansible is agentless (no software needed on
managed nodes), uses SSH for communication, and adopts a human-readable
YAML syntax instead of custom DSLs (domain-specific languages). This makes
it easier to install, learn, and operate, especially for small to mid-sized
teams.
❓3. What do you need to install Ansible and where does it run?
Answer:
You only need to install Ansible on a control node (your local machine,
a management server, etc.). It then connects to managed nodes (servers,
devices) via SSH (Linux/macOS) or WinRM (Windows) to execute tasks. No software
needs to be installed on the managed nodes.
❓4. What is an Ansible Playbook?
Answer:
A playbook is a YAML file that defines a set of tasks for Ansible to perform on
target hosts. Playbooks describe what the system should look like, not
how to achieve that state, making it easier to manage system configurations
declaratively.
❓5. How does Ansible ensure idempotence?
Answer:
Idempotence in Ansible means that applying the same playbook multiple times
produces the same result — no unintended changes. Modules are designed
to detect the current system state and only perform actions if changes are
needed.
❓6. What is Ansible Inventory and how is it used?
Answer:
Ansible Inventory is a file (typically hosts.ini or dynamic inventory scripts)
listing all the machines you want to manage. It organizes hosts into groups
(like [webservers], [dbservers]) and defines connection details for efficient
targeting and task execution.
❓7. Can Ansible manage cloud infrastructure like AWS or Azure?
Answer:
Yes. Ansible has built-in modules for managing cloud resources across AWS,
Azure, GCP, OpenStack, and more. You can provision VMs, configure networks,
manage storage, and deploy apps using the same Ansible playbooks.
❓8. What is Ansible Vault?
Answer:
Ansible Vault is a feature that allows you to encrypt sensitive data
(like passwords, API keys) within your Ansible files. This ensures that secrets
remain protected even if your playbooks are stored in public or shared
repositories.
❓9. How scalable is Ansible for managing large infrastructures?
Answer:
Ansible can scale from managing a few servers to thousands by using
features like dynamic inventory, parallel task execution, and tools like Ansible
AWX/Tower for centralized control, scheduling, and reporting across large
environments.
❓10. Is Ansible suitable only for Linux systems?
Answer:
No. While Ansible is best known for managing Linux and Unix systems, it also
supports Windows systems through WinRM connections and provides specific
modules for Windows tasks like configuring IIS, managing services, and
installing applications.
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