DevOps Classroomnotes 08/Jan/2023

Ansible Contd

Tomcat Playbook optimization

• Refer Here for the rest of steps added
• Generally there are some tasks which need to be executed as a reaction to other task i.e. restart tomcat only when configuration files have changed
• For acheiving the above we need to know about ansible Handlers
• Refer Here for the changes done to include handlers
• The way we copied the same content into two different locations with two different files Refer Here for the changes
• Refer Here for the changes done to include loop in ansible Refer Here
• Lets summarize the improvements which we have done
  • Using Generic modules like package over apt or yum
  • Using variables to parametrize gives us options to set host and group level values
  • conditionally execute tasks based on facts
  • use handlers for automating steps which need not execute every time and they are required based on some changes
  • use loops rather than copy paste of modules

Ansible Handlers

• Refer Here for official docs

Exercise

• Write a playbook to install the following
• ubuntu steps

sudo apt update
sudo apt install apache2
sudo apt install php libapache2-mod-php php-mysql
# create a file /var/www/html/info.php  with following content
<?php
phpinfo();
?> 

• centos steps

sudo dnf install httpd
sudo systemctl enable httpd
sudo systemctl start httpd
sudo dnf install php php-mysqlnd
sudo systemctl restart httpd
# create a file /var/www/html/info.php  with following content
<?php
phpinfo();
?>

• Sample solution – First version

---
- name: install apache server
  become: yes
  tasks:
    - name: install apache on ubuntu
      ansible.builtin.apt:
        name: apache2
        update_cache: yes
        state: present
      when: ansible_facts['distribution'] == "Ubuntu"
      notify:
        - enable and restart apache2
    - name: install apache on centos
      ansible.builtin.dnf:
        name: httpd
        state: present
      notify:
        - enable and restart httpd
      when: ansible_facts['distribution'] == "Centos"
    - name: install php modules
      ansible.builtin.apt:
        name:
          - php
          - libapache2-mod-php
          - php-mysql
        state: present
      when: ansible_facts['distribution'] == "Ubuntu"
      notify:
        - enable and restart apache2
    - name: install php modules on centos
      ansible. builtin.dnf:
        name:
          - php
          - php-mysqlnd
        state: present
       when: ansible_facts['distribution'] == "Centos"
       notify:
        - enable and restart apache2
    - name: copy info.php
      ansible.builtin.copy:
        src: info.php
        dest: /var/www/html/info.php    
  handlers:
    - name: enable and restart apache2
      ansible.builtin.systemd:
        name: apache2
        enabled: yes
        state: restarted
    - name: enable and restart httpd
      ansible.builtin.systemd:
        name: httpd
        enabled: yes
        state: restarted