templating.md

Templating in Ansible

Templating in Ansible

• Sometimes you need dynamic behaviour in plays/tasks
  • File locations
  • Fill in prompted information
  • Secret info (passwords, API keys)
  • Generally sourced from a variable
• Ansible uses a template syntax called Jinja2

Jinja2

• Templating language
• Provides tools for
  • Passing variables
  • Evaluating expressions
  • etc.
• References:
  • Templating in Ansible
  • Jinja2 official docs

Variables

• Simple variables or expressions
  • {{ person_name }}
  • {{ 1 + 1 }}
• Dictionaries
  • {{ lesson['name'] }}
  • {{ lesson.name }}
  • {{ hostvars['myserver'].ansible_distribution }}

Exercise: Templating in our playbook

• Edit vars section in static-site.yml to add:
  • static_file_directory
  • nginx_conf_directory

vars:
  .
  static_file_directory: /usr/share/nginx/html
  nginx_available_conf: /etc/nginx/sites-available
tasks:

Exercise: Templating in our playbook

• Use template syntax to replace path for
  • nginx
  • index.html

 - name: Template in nginx config file
   template:
     .
     dest: "{{ nginx_available_conf }}/mysite.conf"
     .

 - name: Copy up static website html
   template:
     .
     dest: "{{ static_file_directory }}/index.html"
     .

Re-run the ansible playbook

Templates and Quoting

• Be aware that you will often need to put quotes around templated elements

  dest: "{{ nginx_conf_directory }}/mysite.conf"
  

• However sometimes you do not need them

  command: ls {{ nginx_conf_directory }}