Interpretation of single- double quoted value

[Hamdi_Gabsi]

Hi ,

I started my RH294 training, and I am a little bit confused about the interpretation of single- double quoted value in Ansible.

When should I use : 

• "{{ my_var }}"
• {{ my_var }}
• '{{my_var }}'

What is the difference between :

• hosts: 'datacenter*'
• hosts: "datacenter*"

How ansible interprets each case.

Thank you so much.

[Chetan_Tiwary_ · Accepted solution]

Hello @Hamdi_Gabsi !

Thanks for reaching out!

Refer it here : https://docs.ansible.com/ansible/latest/reference_appendices/YAMLSyntax.html#yaml-syntax 

https://docs.ansible.com/ansible/latest/playbook_guide/playbooks_variables.html 

1. "{{ my_var }}" --> case of variable interpolation or Dynamic Injection. Use it when you want to use the actual value of the variable during execution in a string or a command.
2.  '{{ my_var }}' --> case of literal string or Static Injection. No variable interpolation ( means no variable substitution ) is done here. Use it when you want the origial placeholder text rather than it's value. 
3. {{ my_var }} --> same as the first one but generally used for larger strings.

**************************************************************

Regarding second part : 

hosts: 'datacenter*' --> * is interpreted as literal * --> host pattern matching for any host that starts with datacenter.

hosts: "datacenter*" --> wildcard expansion is allowed here --> which will match any string that contains the word "datacenter".

[Hamdi_Gabsi]

Thank you so much  @Chetan_Tiwary_  for these details.

I think it is clear now.

I appreciate your response.

[Chetan_Tiwary_]

Glad it helped @Hamdi_Gabsi ! All the best !