Lamp Contd

• As of now our playbook is as shown below

---
- hosts: webservers
  become: yes
  vars:
    package_apache: apache2
    packages_php_modules:
      - php
      - libapache2-mod-php 
      - php-mysql
      - php-cli
  tasks:
    - name: fail playbook on unsupported platforms
      fail:
        msg: 'This playbook is currently developed only for ubuntu 18'
      when: ansible_distribution != 'Ubuntu'
    - name: update and install apache
      apt: # https://docs.ansible.com/ansible/latest/modules/apt_module.html
        name: "{{ package_apache }}"
        update_cache: yes
        state: present
    - name: restart and enable apache2
      service:
        name: "{{ package_apache }}" 
        enabled: yes 
        state: restarted
    - name: install php modules
      apt:
        name: "{{ item }}"
        state: present
      loop: "{{ packages_php_modules}}"
    - name: restart apache2
      service:
        name: "{{ package_apache }}" 
        state: restarted
      
      

• In the above playbook the problem is restart service is written multiple times and restart apache should happen only when the apache is installed or php modules are installed
• To solve this Ansible has handlers Refer Here
• To understand handlers lets write a simple playbook

---
- hosts: all
  become: yes
  tasks:
    - name: uninstall git
      package:
        name: git
        state: absent
    - name: log message for uninstallation
      debug:
        msg: "git is uninstalled"

• This playbook displays git is uninstalled message every time, but actually it has to display the message when git is uninstalled by ansible, so using handlers will solve the issue

---
- hosts: all
  become: yes
  tasks:
    - name: uninstall git
      package:
        name: git
        state: absent
      notify:
        - log message for uninstallation
  handlers:
    - name: log message for uninstallation
      debug:
        msg: "git is uninstalled"

• Now in the same approach if we add handlers to handle service restarts our playbook will look like

---
- hosts: webservers
  become: yes
  vars:
    package_apache: apache2
    packages_php_modules:
      - php
      - libapache2-mod-php 
      - php-mysql
      - php-cli
  tasks:
    - name: fail playbook on unsupported platforms
      fail:
        msg: 'This playbook is currently developed only for ubuntu 18'
      when: ansible_distribution != 'Ubuntu'
    - name: update and install apache
      apt: # https://docs.ansible.com/ansible/latest/modules/apt_module.html
        name: "{{ package_apache }}"
        update_cache: yes
        state: present
      notify:
        - debug message for apache installation
        - restart and enable apache2
    - name: install php modules
      apt:
        name: "{{ item }}"
        state: present
      loop: "{{ packages_php_modules}}"
      notify:
        - debug message for php modules
        - restart and enable apache2
  handlers:
    - name: restart and enable apache2
      service:
        name: "{{ package_apache }}" 
        enabled: yes 
        state: restarted
    - name: debug message for apache installation
      debug:
        msg: "{{ package_apache }} is installed"
    - name: debug message for php modules
      debug:
        msg: "php modules are installed"
      

• We have one last step of creating a file called as info.php in /var/www/html/info.php with following content

<?php
phpinfo();
?>

• This step means we have to create a file. Creating a file can be done into two ways
  • If the file is available on some url download the file
  • Copy the file from your system into server whereever you want to run
• For file demo use this playbook

---
- hosts: all
  tasks:
    - name: create an empty file # This module creates an empty file on node
      file:
        path: /home/devops/readme.txt
        state: touch
    - name: copy the files on your server # This module creates a symlink between two files on the node
      file:
        src: /home/devops/readme.txt
        dest: /home/devops/readmecopy.txt
        state: link
    - name: create directory # This module creates empty directory on node
      file:
        path: /home/devops/temp
        state: directory
    - name: download file from url # This module downloads the file from url into node
      get_url:
        url: https://war-jar-files.s3-us-west-2.amazonaws.com/gameoflife.war 
        dest: /home/devops/gameoflife.war
    - name: copy the file from acs to node # This module copies the file from acs to node
      copy:
        src: demo.txt
        dest: /home/devops/demo.txt

• Create info.php in the folder where you are writing playbook with following content

<?php
phpinfo();
?>

• Now use copy module to copy this info.php to node and the playbook looks like below

---
- hosts: webservers
  become: yes
  vars:
    package_apache: apache2
    packages_php_modules:
      - php
      - libapache2-mod-php 
      - php-mysql
      - php-cli
  tasks:
    - name: fail playbook on unsupported platforms
      fail:
        msg: 'This playbook is currently developed only for ubuntu 18'
      when: ansible_distribution != 'Ubuntu'
    - name: update and install apache
      apt: # https://docs.ansible.com/ansible/latest/modules/apt_module.html
        name: "{{ package_apache }}"
        update_cache: yes
        state: present
      notify:
        - debug message for apache installation
        - restart and enable apache2
    - name: install php modules
      apt:
        name: "{{ item }}"
        state: present
      loop: "{{ packages_php_modules}}"
      notify:
        - debug message for php modules
        - restart and enable apache2
    - name: copy info.php
      copy:
        src: info.php
        dest: /var/www/html/info.php
      notify:
        - restart and enable apache2
  handlers:
    - name: restart and enable apache2
      service:
        name: "{{ package_apache }}" 
        enabled: yes 
        state: restarted
    - name: debug message for apache installation
      debug:
        msg: "{{ package_apache }} is installed"
    - name: debug message for php modules
      debug:
        msg: "php modules are installed"
      

• After this navigate to url http://<publicip>/info.php and you should see the php test page.

• Exercise: Make this work for centos 7 as well using docs over here

• In the next class we would configure tomcat on linux machines and learn the subsequent ansible topics along with that.