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

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

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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