Statements in Ansible
Hello Everyone
Welcome to CloudAffaire and this is Debjeet.
In the last blog post, we have discussed operators in Ansible.
https://cloudaffaire.com/operators-in-ansible/
In this blog post, we will discuss statements in Ansible.
What is a statement?
In computer programming, a statement is a syntactic unit of an imperative programming language that expresses some action to be carried out. A statement can be used as conditional or iterative. As already referenced in the variables section, Ansible uses Jinja2 templating to enable dynamic expressions and access to variables. Ansible supports all the statements provided by Jinja2 like if else, for etc.
Next, we are going to explain each statement with a demo.
Conditional Statements: A conditional statement defines a condition for execution. Ansible supports conditional statements like when, if, if else, if elif else etc.
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## Conditional statements ## ########## ## when ## ########## ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: Simple When Statement vars: a: 10 debug: msg: "{{ a }} is greater than 5" when: a > 5 ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: Complex When Statement vars: a: 10 debug: msg: "{{ a }} is greater than 5 and less than 15" when: (a > 5 and a < 15) or (a < 100 and a > 20) ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ######## ## If ## ######## ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: If Statement vars: a: 10 debug: msg: "{{ a if (a > 5) }}" ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ############# ## If else ## ############# ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: If else Statement vars: a: 10 b: 20 debug: msg: "{{ a if (a > 10) else b }}" ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ################## ## If elif else ## ################## ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: If elif else Statement vars: a: 20 b: 30 c: 10 debug: msg: "{% if (a > b and a > c) %} {{ a }} {% elif (b > a and b > c) %} {{ b }} {% else %} {{ c }} {% endif %}" ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml |
Iterative Statements: An iterative statement is used to iterate through a list of items. Ansible supports different iterative statements like loop, with_X, for etc.
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## Iterative statements ## ########## ## loop ## ########## ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: loop Statement debug: msg: "{{ item }}" loop: [1, 2, 3, 4, 5, 6] ---------------------- :wq #Note: loop Required Ansible Version >= 2.5 ## Execute the playbook ansible-playbook myplaybook.yml ################ ## with_items ## ################ ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_items Statement debug: msg: "{{ item }}" with_items: [1, 2, 3, 4, 5, 6] ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ############### ## with_list ## ############### ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_list Statement debug: msg: "{{ item }}" with_list: [1, 2, 3, 4, 5, 6] ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ######################## ## with_indexed_items ## ######################## ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_indexed_items Statement debug: msg: "Position = {{ item.0 }} : Value = {{ item.1 }}" with_indexed_items: [1, 2, 3, 4, 5, 6] ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml #################### ## with_flattened ## #################### ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_flattened Statement debug: msg: "{{ item }}" with_flattened: [[1, 2], [3, 4], [5, 6]] ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ################### ## with_together ## ################### ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_together Statement debug: msg: "{{ item.0 }} : {{ item.1 }} : {{ item.2 }}" with_together: [[1, 2, 3], [4, 5, 6], [7, 8, 9]] ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ############### ## with_dict ## ############### ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_dict Statement debug: msg: "{{item.key}}: {{item.value}}" with_dict: {a: 1, b: 2, c: 3} ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ################### ## with_sequence ## ################### ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_sequence Statement debug: msg: "{{ item }}" with_sequence: start=1 end=8 stride=2 format=user%02x ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ###################### ## with_subelements ## ###################### ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: no vars: employee: - name: Debjeet details: - id: 1 country: "india" - name: Alex details: - id: 2 country: "usa" tasks: - name: with_subelements Statement debug: msg: "{{ item.0.name }} : {{ item.1.id}} : {{ item.1.country}}" with_subelements: - "{{ employee }}" - details ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ################# ## with_nested ## ################# ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_nested Statement debug: msg: "{{ item.0 }} : {{ item.1 }}" with_nested: - [1, 2, 3] - [a, b, c] ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml ######################## ## with_random_choice ## ######################## ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: with_random_choice Statement debug: msg: "{{ item }}" with_random_choice: [1, 2, 3, 4] ---------------------- :wq ## Execute the playbook multiple times to get random output ansible-playbook myplaybook.yml ansible-playbook myplaybook.yml ansible-playbook myplaybook.yml ######### ## for ## ######### ## Create playbook vi myplaybook.yml ---------------------- - hosts: localhost gather_facts: false tasks: - name: for Statement debug: msg: "{% for i in range(4) %} {{ i }} {% endfor %}" ---------------------- :wq ## Execute the playbook ansible-playbook myplaybook.yml |
Hope you have enjoyed this article. In the next blog post, we will discuss functions in Ansible.
To get more details on Ansible, please refer below Ansible documentation.