Working with Ansible conditionals | How to Use When Statement in Ansible | linuxtopic

Working with Ansible conditionals | How to Use When Statement in Ansible | linuxtopic

conditional is used to change a ansible play behavior based on there facts/variable. we can control which tasks/roles will be run or skipped on there targeted hosts/nodes with the help of when statement

ansible "when statement" example : we will create a condition.yml playbook

To Create yml playbook file, choose any name

cd  /etc/ansiblevi condition.yml

---
- hosts: all


  tasks:
  - name: get uptime
    command: uptime
    when: ansible_facts['os_family'] == "Debian"
    register: uptime


  - debug: var=uptime.stdout

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add  remote hosts on inventory  Click Here...

To run ansible playbook on hosts

ansible-playbook   condition.yml


We can see that, localhost is CentOS 7 so task has been skipped and 192.168.3.104 is Debian so task executed.

Again we update condition in playbook, we add change !=

---
- hosts: all


  tasks:
  - name: get uptime
    command: uptime
    when: ansible_facts['os_family'] != "Debian"
    register: uptime


  - debug: var=uptime.stdout

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Ansible Conditionals - When Statement 

Again we run playbook

ansible-playbook   condition.yml


Now  task has been executed on  CentOS 7 and skipped on Debian.

Method 2:

Now we will use ansible facts as variable like ansible_distribution, following playbook

---
- hosts: all


  tasks:
  - name:  echo distribution - CentOS
    command: echo CentOS-PC
    when: ansible_distribution == "CentOS"
    register: centos

We can use AND condition  with following examples

---
- hosts: all


  tasks:
  - name:  echo distribution - CentOS
    command: echo CentOS-PC
    when: ansible_distribution == "CentOS"  and ansible_architecture == "x86_64"
    register: centos


 - debug: var=uptime.stdout


ansible-playbook  condition.yml


Now we will add more condition with and statement, and use loop to display all results. Our final playbook is :

---
- hosts: all


  tasks:
  - name:  echo distribution - CentOS
    command: echo CentOS-PC
    when: ansible_distribution == "CentOS"  and ansible_architecture == "x86_64"
    register: centos


  - name:  echo distribution - Ubuntu
    command: echo Ubuntu-PC
    when: ansible_distribution == "Ubuntu"  and ansible_architecture == "x86_64"
    register: ubuntu


  - debug: var={{ item }}
    loop:
      - centos.stdout
      - ubuntu.stdout


Now we will execute ansible playbook

ansible-playbook  condition.yml


Thanks

End of this ansible conditionals  tutorial,  we need your support so i request you to please comment if something missed by me, share and like this post.


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