⚙️ Configuration Management & Orchestration

🌐 Environment Setup

Initiating a Docker container named "nginx-container" using the latest NGINX image, and starts a Bash shell inside the container for interactive usage.

docker run -it --name nginx-container nginx:latest /bin/bash

Making sure everything is correctly configured

root@23c06c085cbe:/# ansible all -i 'localhost,' -c local -m ping

localhost | SUCCESS => {

"changed": false,

"ping": "pong"

}

Generating key pairs, if never used we need to have openssh installed and the .ssh folder is created automatically

root@23c06c085cbe:/# ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa):

Created directory '/root/.ssh'.

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /root/.ssh/id_rsa.

🛠️ Installation

sudo dnf install -y epel-release &&  # Install EPEL repository for Ansible
sudo dnf install -y ansible &&       # Install Ansible
ansible all -m ping                  # Ping all hosts to test connectivity

🔧 Foundation

🗂️ Inventory

Viewing the Inventory

List all hosts in your inventory: ansible all --list-hosts
Display detailed information about all hosts in your inventory: ansible-inventory --list --yaml
Check the syntax of your inventory file: ansible-inventory --inventory-file=your_inventory_file --syntax-check

🖥️ Host

Basic Commands

Ping all hosts in the inventory: ansible all -m ping
Ping a specific host group: ansible webservers -m ping
Execute a command on all hosts: ansible all -a "uptime"
Gather facts from all hosts: ansible all -m setup
Check if a specific service is running: ansible all -m service -a "name=nginx state=started"

Ad-hoc Commands

Install a package on all hosts: ansible all -m apt -a "name=htop state=present" --become
Copy a file to all hosts: ansible all -m copy -a "src=/local/path dest=/remote/path"
Run a command with a non-default user: ansible all -a "df -h" -u username

📋 Tasks

Playbooks and Tasks

Run a playbook: ansible-playbook playbook.yml
Check the syntax of a playbook: ansible-playbook playbook.yml --syntax-check
List all tasks that will be executed in a playbook: ansible-playbook playbook.yml --list-tasks
Execute specific tasks in a playbook using tags: ansible-playbook playbook.yml --tags "tag1,tag2"
Skip specific tasks in a playbook using tags: ansible-playbook playbook.yml --skip-tags "tag1,tag2"
Run a playbook in check mode (dry run): ansible-playbook playbook.yml --check

Task Examples

Install a package: - name: Install htop apt: name: htop state: present
Start and enable a service: - name: Ensure nginx is started and enabled service: name: nginx state: started enabled: true
Copy a file to a remote host: - name: Copy nginx configuration file copy: src: /local/path/nginx.conf dest: /etc/nginx/nginx.conf
Create a user: - name: Create a user user: name: john state: present groups: "sudo"
Add a cron job:
- name: Add a cron job cron: name: "backup" minute: "0" hour: "2" job: "/usr/local/bin/backup.sh"

📜 PlayBooks

Basic Playbook Structure:

 - hosts: webservers
   tasks:
     - name: Ensure Nginx is installed
       apt:
         name: nginx
         state: present

For playbook inventory Visit Github > Luminalink-AI/Playbooks

**WARNING: This repository contains sensitive data, DO NOT SHARE**

A list of reusable playbooks will be inplemented in this section

1. Ad Hoc Commands

Ping all hosts: ansible all -m ping
Run a command on all hosts: ansible all -a "uptime"
Gather facts from all hosts: ansible all -m setup
Check if a specific service is running: ansible all -m service -a "name=nginx state=started" `
Install a package on all hosts: ansible all -m apt -a "name=htop state=present" --become
Copy a file to all hosts: ansible all -m copy -a "src=/local/path dest=/remote/path"
Run a command with a non-default user: ansible all -a "df -h" -u username

2. Introduction

Ansible Basics:

Inventory File: Define your inventory in a file (e.g., hosts):

[webservers]
web1.example.com
web2.example.com

[dbservers]
db1.example.com
db2.example.com

Running Ansible Commands:
- Ping all hosts in the inventory: ansible all -m ping -i hosts
- Execute a command on all hosts: ansible all -a "uptime" -i hosts

3. Packages (apt, become, with_items)

Install Packages with apt:

Single Package:

- name: Install htop
  apt:
    name: htop
    state: present

Multiple Packages using with_items:

- name: Install multiple packages
  apt:
    name: "{{ item }}"
    state: present
  with_items:
    - htop
    - git
    - curl

Using become for Privileged Tasks:

Ensure Nginx is installed and started:

- name: Ensure Nginx is installed and started
  apt:
    name: nginx
    state: present
  become: yes

- name: Ensure Nginx is running
  service:
    name: nginx
    state: started
  become: yes

Create a User with sudo Privileges:

- name: Create a user with sudo privileges
  user:
    name: john
    state: present
    groups: sudo
  become: yes

🛎️ Services

1. Roles

Roles in Ansible are a way to organize playbooks into reusable units. Roles can include tasks, handlers, variables, templates, and files.

Creating a Role:

Create a Role Directory Structure:

ansible-galaxy init <role_name>

This creates the following structure:

<role_name>/
├── defaults
│   └── main.yml
├── files
├── handlers
│   └── main.yml
├── meta
│   └── main.yml
├── tasks
│   └── main.yml
├── templates
├── tests
│   ├── inventory
│   └── test.yml
└── vars
    └── main.yml

Using a Role in a Playbook:

---
- hosts: webservers
  roles:
    - role: <role_name>

2. Overview

Roles provide a structured way to group tasks, handlers, variables, and other Ansible components. They help in reusing and organizing code.

Benefits of Using Roles:

Modular and reusable code
Simplifies playbook management
Easy to share and maintain

3. Converting to Roles: Tasks, Handlers

To convert existing tasks and handlers into a role, follow these steps:

Create the Role:

ansible-galaxy init my_role

Move Tasks to the Role:

Copy tasks from your playbook to my_role/tasks/main.yml.

Move Handlers to the Role:

Copy handlers from your playbook to my_role/handlers/main.yml.

Advanced Concepts

1. Advanced Execution Introduction

Advanced execution in Ansible involves optimizing and customizing playbook runs using features like limits, tags, and conditions.

2. Limiting Execution by Hosts: `limit`

The limit option restricts playbook execution to specific hosts.

Example:

ansible-playbook site.yml --limit webservers

3. Removing Unnecessary Steps: `gather_facts`

The gather_facts option controls whether Ansible collects facts about the hosts.

Example:

---
- hosts: all
  gather_facts: no
  tasks:
    - name: Simple task
      debug:
        msg: "No facts gathered"

4. Extracting Repetitive Tasks: `cache_valid_time`

The cache_valid_time option caches facts to avoid gathering them multiple times.

Example:

---
- hosts: all
  gather_facts: yes
  facts:
    cache_valid_time: 3600
  tasks:
    - name: Use cached facts
      debug:
        var: ansible_facts

5. Limiting Execution by Tasks: `tags`

Tags allow you to run specific tasks within a playbook.

Example:

---
- hosts: all
  tasks:
    - name: Install package
      apt:
        name: vim
        state: present
      tags: install

    - name: Configure file
      copy:
        src: /src/file
        dest: /dest/file
      tags: config

Run only the tasks with the install tag:

ansible-playbook site.yml --tags install

6. Idempotence: `changed_when`, `failed_when`

Idempotence ensures that running a playbook multiple times results in the same state.

Using changed_when:

---
- name: Check if file exists
  stat:
    path: /path/to/file
  register: file_stat

- name: Create file if not exists
  file:
    path: /path/to/file
    state: touch
  changed_when: not file_stat.stat.exists

Using failed_when:

---
- name: Check if directory exists
  stat:
    path: /path/to/dir
  register: dir_stat

- name: Fail if directory does not exist
  fail:
    msg: "Directory does not exist"
  failed_when: not dir_stat.stat.exists

Troubleshooting, Testing & Validation

Troubleshooting Ansible Playbooks:

Verbose Mode:

Run playbooks with increased verbosity to get more detailed output.

ansible-playbook site.yml -vvv

Check Mode:

Run playbooks in check mode to see what changes would be made without actually applying them.

ansible-playbook site.yml --check

Dry Run:

Combine check mode with verbosity for a detailed dry run.

ansible-playbook site.yml --check -vvv

Testing & Validation:

YAML Syntax:

Use yamllint to check the syntax of your YAML files.

yamllint playbook.yml

Playbook Syntax:

Use ansible-playbook --syntax-check to check the syntax of your playbooks.

ansible-playbook site.yml --syntax-check

Role Testing:

Use Molecule to test Ansible roles.

pip install molecule
molecule init role my_role
molecule test

⚙️ Configuration Management & Orchestration

🌐 Environment Setup

🛠️ Installation

🔧 Foundation

🗂️ Inventory​

🖥️ Host​

📋 Tasks​

📜 PlayBooks​

1. Ad Hoc Commands​

2. Introduction​

3. Packages (apt, become, with_items)​

🛎️ Services

1. Roles​

2. Overview​

3. Converting to Roles: Tasks, Handlers​

Advanced Concepts​

1. Advanced Execution Introduction​

2. Limiting Execution by Hosts: limit​

3. Removing Unnecessary Steps: gather_facts​

4. Extracting Repetitive Tasks: cache_valid_time​

5. Limiting Execution by Tasks: tags​

6. Idempotence: changed_when, failed_when​

Troubleshooting, Testing & Validation​

🗂️ Inventory

🖥️ Host

📋 Tasks

📜 PlayBooks

1. Ad Hoc Commands

2. Introduction

3. Packages (apt, become, with_items)

1. Roles

2. Overview

3. Converting to Roles: Tasks, Handlers

Advanced Concepts

1. Advanced Execution Introduction

2. Limiting Execution by Hosts: `limit`

3. Removing Unnecessary Steps: `gather_facts`

4. Extracting Repetitive Tasks: `cache_valid_time`

5. Limiting Execution by Tasks: `tags`

6. Idempotence: `changed_when`, `failed_when`

Troubleshooting, Testing & Validation