YAML

• YAML is a file format which is designed over name value pairs
• YAML is used to represent data
• YAML files have extension of .yml or .yaml
• Any thing in yaml

<name>: <value>

• Data is categorized into following types
  • number:
    yaml
experience: 4
  • text
    yaml
designation: DevOps Engineer
  • boolean
    yaml
certifications: yes
  • list/array
    “`yaml
    tools:</li>
    <li>ansible</li>
    <li>docker</li>
    <li>k8s
    “`
  • map/object/dictionary
    yaml
address:
flatno: 601
building: nilgiri
landmark: ameerpet metro
city: hyderabad
• Scalar or simple types
  • number
  • text
  • boolean
• Complex
  • list
  • map
• Example 1 : Ansible Playbook

---
- name: Install and configure Nginx web server
  hosts: webservers
  become: true
  gather_facts: yes
  tasks:
    - name: Display OS information
      debug:
        var: ansible_distribution

    - name: Update apt cache
      apt:
        update_cache: yes

    - name: Install Nginx web server
      apt:
        name: nginx
        state: latest

    - name: Start Nginx service
      service:
        name: nginx
        state: started

• Structure:
  • list(map/object)
    • name: string
    • become: boolean
    • gather_facts: boolean
    • tasks: list(map/object)
      • name: string
      • debug:
        
• Example

trigger: #list(text)
- main

pool: #map/object
  vmImage: 'ubuntu-latest'  #text

stages: # list(map/object)
- stage: Build
  displayName: 'Build Stage'
  jobs:
  - job: BuildJob
    displayName: 'Build Job'
    steps:
    - script: echo "Building the application..."
      displayName: 'Build Step'

    - task: DotNetCoreCLI@2
      inputs:
        command: 'restore'
        projects: '**/*.csproj'

    - task: DotNetCoreCLI@2
      inputs:
        command: 'build'
        projects: '**/*.csproj'
        arguments: '--configuration Release'

- stage: Test
  displayName: 'Test Stage'
  jobs:
  - job: TestJob
    displayName: 'Test Job'
    steps:
    - script: echo "Running tests..."
      displayName: 'Test Step'

    - task: DotNetCoreCLI@2
      inputs:
        command: 'test'
        projects: '**/*.csproj'
        arguments: '--configuration Release --no-build'

- stage: Deploy
  displayName: 'Deploy Stage'
  jobs:
  - job: DeployJob
    displayName: 'Deploy Job'
    steps:
    - script: echo "Deploying the application..."
      displayName: 'Deploy Step'

    - task: AzureWebApp@1
      inputs:
        azureSubscription: '<YourAzureSubscription>'
        appType: 'webApp'
        WebAppName: '<YourWebAppName>'
        packageForLinux: '$(System.DefaultWorkingDirectory)/**/*.zip'

• Example

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

• Refer Here for yaml syntax
• In devops we use yaml in many tools, each tool has a schema or structure defined and we need to follow.

Ansible Playbook

• Ansible Playbook is written in YAML format
• Structure
  
• In each Playbook task is the atomic activity (smallest unit of work) & is achevied with the help of module
• A module is where we can express what we want
• Way of Working
  • List down manual steps and ensure they are working
  • try to find a module for each manual step

Trying the above way of working

Sample 1

• manual steps

wget https://www.free-css.com/assets/files/free-css-templates/download/page296/oxer.zip
unzip oxer.zip

• Finding ansible modules
  • approach 1: Refer Here for module list
  • approach 2: google <command> in ansible
    
• Module expressed in playbook as a task

---
- name: this is sample playbook
  hosts: all
  become: no
  tasks:
    - name: download the zip file
      <module-name>:
         <parameter-1>: 
         #..
         <paramter-n>:
         #[state]: 

• Lets fill the download file

---
- name: this is sample playbook
  hosts: all
  become: no
  tasks:
    - name: download the zip file
      ansible.builtin.get_url:
        url: https://www.free-css.com/assets/files/free-css-templates/download/page296/oxer.zip
        dest: /tmp/oxer.zip
    - name: unzip the file
      ansible.builtin.unarchive:
        dest: /tmp/oxer
        src: /tmp/oxer.zip

Sample 2

• Manual steps

touch /tmp/1.txt
mkdir /tmp/test

• Playbook structure

---
- name: this is sample playbook
  hosts: all
  become: no
  tasks:
    - name: create a file
      ansible.builtin.file:
        path: /tmp/1.txt
        state: touch
    - name: create a directory
      ansible.builtin.file:
        path: /tmp/test
        state: directory

Sample 3

• I want to install apache, php in the ubuntu 22.04 Refer Here

sudo apt update
sudo apt install apache2 -y
sudo apt install php libapache2-mod-php php-mysql

• Playbook

- name: install apache and php
  become: yes
  hosts: all
  tasks:
    - name: install apache
      ansible.builtin.apt:
        name: apache2
        update_cache: yes
        state: present
    - name: install php packages
      ansible.builtin.apt:
        name:
          - php
          - libapache2-mod-php
          - php-mysql
        state: present