DevOps Classroom Series -13/Nov/2019

Goal: Write Common Tasks and Handlers

• From Previous Series this playbook will be our starting point

---
- hosts: all
  become: yes
  tasks:
    - name: install httpd
      yum: 
        name: httpd
        state: present
      notify:
        - restart and enable httpd
      when: ansible_facts['os_family'] == "RedHat"
    - name: install php modules
      yum:
        name: "{{ item }}"
        state: present
      loop:
        - php
        - php-mysql
      notify:
        - restart and enable httpd
      when: ansible_facts['os_family'] == "RedHat"
    - name: install apache2 and update packages
      apt:
        name: apache2
        update_cache: yes
        state: present
      notify:
        - restart and enable apache2
      when: ansible_facts['os_family'] == "Debian"
    - name: install php modules
      apt:
        name: "{{ item }}"
        state: present
      loop:
        - php
        - libapache2-mod-php
        - php-mysql
        - php-cli
      notify:
        - restart and enable apache2
      when: ansible_facts['os_family'] == "Debian"
  handlers:
    - name: restart and enable httpd
      service:
        name: httpd
        enabled: yes
        state: restarted
      when: ansible_facts['os_family'] == "RedHat"
    - name: restart and enable apache2
      service:
        name: apache2
        enabled: yes
        state: restarted
      when: ansible_facts['os_family'] == "Debian"

• To replace apt or yum we can use package module. In the current Scenario, Package names are different for RedHat and Ubuntu
• Lets use Ansible Variables to remove the package name hard coding.
• Approach 1: Define Variables in inventory files.
• Initial Inventory looks as shown below

172.31.26.196
172.31.25.93

• Lets add Groups to the inventory to something like below in inventory file

[ubuntu]
172.31.26.196

[redhat]
172.31.25.93

[webservers]
172.31.26.196 
172.31.25.93  

• Lets add the variable package_name to webserver group as shown below

[ubuntu]
172.31.26.196

[redhat]
172.31.25.93

[webservers]
172.31.26.196 package_name=apache2
172.31.25.93  package_name=httpd

• For now lets comment the install php modules section

---
- hosts: all
  become: yes
  tasks:
    - name: install httpd
      yum: 
        name: httpd
        state: present
      notify:
        - restart and enable httpd
      when: ansible_facts['os_family'] == "RedHat"
    #- name: install php modules
    #  yum:
    #    name: "{{ item }}"
    #    state: present
    #  loop:
    #    - php
    #    - php-mysql
    #  notify:
    #    - restart and enable httpd
    #  when: ansible_facts['os_family'] == "RedHat"
    - name: install apache2 and update packages
      apt:
        name: apache2
        update_cache: yes
        state: present
      notify:
        - restart and enable apache2
      when: ansible_facts['os_family'] == "Debian"
    #- name: install php modules
    #  apt:
    #    name: "{{ item }}"
    #    state: present
    #  loop:
    #    - php
    #    - libapache2-mod-php
    #    - php-mysql
    #    - php-cli
    #  notify:
    #    - restart and enable apache2
    #  when: ansible_facts['os_family'] == "Debian"
  handlers:
    - name: restart and enable httpd
      service:
        name: httpd
        enabled: yes
        state: restarted
      when: ansible_facts['os_family'] == "RedHat"
    - name: restart and enable apache2
      service:
        name: apache2
        enabled: yes
        state: restarted
      when: ansible_facts['os_family'] == "Debian"

• Now Replace apt and yum with package module and also replace all in hosts with webservers

---
- hosts: webservers
  become: yes
  tasks:
    - name: install apache
      package: 
        name: "{{ package_name }}"
        state: present
      notify:
        - restart and enable apache
      when: ansible_facts['os_family'] == "RedHat" or ansible_facts['os_family'] == "Debian"
  handlers:
    - name: restart and enable apache
      service:
        name: "{{ package_name }}"
        enabled: yes
        state: restarted
      when: ansible_facts['os_family'] == "RedHat" or or ansible_facts['os_family'] == "Debian"

• Now lets write the same inventory in YAML format with modules included

all:
  children:
    webservers:
      hosts:
        172.31.26.196:
          package_name: ubuntu
          php-modules:
            - php
            - libapache2-mod-php
            - php-mysql
            - php-cli
        172.31.25.93:
          package_name: httpd
          php-modules:
            - php
            - php-mysql

• Now lets use php-modules variable in playbook to install modules
• Ensure you use a debug module to print variables
• Right now playbook is

---
- hosts: webservers
  become: yes
  tasks:
    - name: install apache
      package: 
        name: "{{ package_name }}"
        state: present
      notify:
        - restart and enable apache
      when: ansible_facts['os_family'] == "RedHat" or ansible_facts['os_family'] == "Debian"
    - name: printing php modules
      debug:
        var: php-modules
    - name: install php modules
      package:
        name: "{{ item }}"
        state: present
      notify:
        - restart and enable apache
      when: ansible_facts['os_family'] == "RedHat" or ansible_facts['os_family'] == "Debian"
      loop: "{{ php-modules }}"
  handlers:
    - name: restart and enable apache
      service:
        name: "{{ package_name }}"
        enabled: yes
        state: restarted
      when: ansible_facts['os_family'] == "RedHat" or or ansible_facts['os_family'] == "Debian"

• php-modules is not recognized as variable, find the resolution.