❗ Idempotence in Ansible

🔰 RECTIFICATION : Restarting HTTPD Service is not
idempotence in nature and also consume more
resources suggest a way to rectify this challenge
in Ansible playbook

Lets see how we can rectify this challenge ….

🟥Using when Keyword: Conditional expression, determines if an iteration of a task is run or not…..

🟥Using handlers : Handlers are just like regular tasks in an Ansible playbook (see Tasks) but are only run if the Task contains a notify directive and also indicates that it changed something. For example, if a config file is changed, then the task referencing the config file templating operation may notify a service restart handler.

✍While ,we copy webpage to directory /var/www/html(root_document)
we have register the variable : rootdoc which will keep track of changes / updation made in directory

- name : "Copying wepages to server"
    tags : rootdoc
    copy :      
      src : index.html
      dest : /var/www/html/
    register : rootdoc

👉 Now we have rootdoc as notifier , we can use this in the when keyword , that is if we have changes to directory restart the service else leave it untouched if running ……

- name : Service status
    service :
      name : httpd
      state : restarted 
    when : rootdoc.changed == true

Thus , we can achieve idempotence using WHEN keyword

The entire playbook is wriiten as followed :

- hosts: 192.168.0.126
  tasks:
  - name : Mounting dvd
    mount : 
      src : "/dev/cdrom"
      path : "/dvd"
      state : mounted 
      fstype : "iso9660"
- name : "Setting up yum repo"
    yum_repository :
      name : yum1
      description : "Yum repo 1"
      baseurl : "/dvd/AppStream"
      gpgcheck : 0
- name : "Setting yum repo "
    yum_repository :
      name : yum2
      description : "Yum repo 2"
      baseurl : "/dvd/BaseOS"
      gpgcheck: 0
- name : "Installing net-tools for cli "
    yum : 
      name : net-tools
      state : present
        
  - name : "Installing httpd package"
    yum : 
     name : httpd
     state : present
- name : "Copying wepages to server"
    tags : rootdoc
    copy :      
      src : index.html
      dest : /var/www/html/
    register : rootdoc
    
  - debug : 
      msg : "{{ rootdoc }}"
- name : "Starting httpd server"
    service : 
      name : httpd
      state : started
      enabled : yes    
    ignore_errors: yes
- name : Service status
    service :
      name : httpd
      state : restarted 
    when : rootdoc.changed == true

🎫Github link : Idempotemce_httpd

Keep learning …..🎁

Keep Motivating 🏆