Ansible in a Nutshell
What is Ansible?
Ansible is like a magic wand for system administrators.
You write some YAML, wave your SSH key, and boom!
Servers are configured, applications are deployed, and your DevOps team thinks you’re a genius (until they see your YAML indentation errors). (hahaha)
A Brief History of Ansible (Or How We Got Here)
Ansible was created in 2012 by Michael DeHaan, who must have been tired of writing the same Bash scripts over and over.
Instead of spending hours debugging shell scripts, he decided to make a tool that could automate infrastructure easily, with no agents or extra dependencies. Thus, Ansible was born!
(Software engineers had tedious things - so we invent things.. sometimes people use our things and think our things are too tedious… so they invent more things.. the world is full of things… and this is why….)
In 2015, Red Hat acquired Ansible, proving that if you make a good enough open-source tool, eventually someone will throw money at you.
Infrastructure as Code (IaC) - The Big Picture
If you’ve ever heard the phrase “treat your servers like cattle, not pets,” then you already get the gist of Infrastructure as Code. Instead of manually configuring each server like a delicate bonsai tree, IaC lets you define everything in code so that it can be automated, version-controlled, and replicated.
Ansible takes this a step further by making sure you don’t need a Ph.D. in YAML just to get things working (though it helps).
🏆 Ansible vs. Puppet
- Ansible: Agentless, uses SSH, simple to set up.
- Puppet: Uses agents, requires a master node, more complex but powerful.
🏆 Ansible vs. Chef
- Ansible: Uses YAML (easy to read, but can be annoying to debug).
- Chef: Uses Ruby (which means, if you’re not a Ruby dev, good luck).
- Ansible: Great for configuration management and app deployment.
- Terraform: Great for infrastructure provisioning (they actually work well together!).
Common Ansible Examples
1. Installing Packages
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| - name: Install Nginx
hosts: web_servers
tasks:
- name: Install Nginx
apt:
name: nginx
state: present
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2. Starting a Service
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| - name: Start and Enable Nginx
hosts: web_servers
tasks:
- name: Start Nginx
service:
name: nginx
state: started
enabled: yes
|
3. Copying a File
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| - name: Copy Config File
hosts: all
tasks:
- name: Copy nginx.conf
copy:
src: ./nginx.conf
dest: /etc/nginx/nginx.conf
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4. Running a Shell Command
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| - name: Check Disk Usage
hosts: all
tasks:
- name: Run df command
command: df -h
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5. Creating a User
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| - name: Create a User
hosts: all
tasks:
- name: Add User
user:
name: devops
state: present
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6. Deploying an App
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| - name: Deploy Web App
hosts: web_servers
tasks:
- name: Pull latest code
git:
repo: 'https://github.com/example/repo.git'
dest: /var/www/html
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7. Managing Firewall Rules
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| - name: Open Port 80
hosts: all
tasks:
- name: Allow HTTP traffic
ufw:
rule: allow
port: 80
proto: tcp
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8. Configuring a Database
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| - name: Configure MySQL
hosts: db_servers
tasks:
- name: Ensure MySQL is installed
apt:
name: mysql-server
state: present
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9. Using Variables
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| - name: Install Custom Package
hosts: all
vars:
package_name: htop
tasks:
- name: Install package
apt:
name: "{{ package_name }}"
state: present
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10. Looping Over Tasks
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| - name: Install Multiple Packages
hosts: all
tasks:
- name: Install common tools
apt:
name: [vim, curl, git]
state: present
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Key Ideas
| Topic | Summary |
|---|
| What is Ansible? | A simple, agentless automation tool using YAML. |
| History | Created in 2012, acquired by Red Hat in 2015. |
| Infrastructure as Code | Managing servers using code instead of manual setup. |
| Comparison | Competes with Puppet, Chef, Terraform (but works well with Terraform). |
| Common Usage | Configuration management, deployment, provisioning. |
Reference Links
