Var

Define Var in Playbook

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vars:
  http_port: 80
...
tasks:
- name: xxx
  firewalld: port={{http_port}}
  

Define Var in File

file:

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http_port:80

usage

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- hosts: web
  vars_files:
    - vars/server_vars.yml

Var Trap

sometimes YAML and ansible playbook cannot work together. when it report syntex error, you could try add quote.

Facts

Facts are the information of remote hosts collected by ‘setup’ module.

we can directly use the vars in ansible all -m setup -u root like {{some_vars}}

the vars we collected will be in a json format, we could use . to access different level of json like {{ansible_ens3.ipv4.address}}

Register Vars

we can register var in the playbook and use it later.

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- hosts: web
  tasks:
    - shell: ls
      register: result
      ignore_errors: True
    - shell: echo "{{ result.stdout }}"
      when: result.rc == 5

Pass Vars Through CMD

we could use

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ansible-playbook xxx.yml --extra-vars "hsots=web user=root"

to pass vars to playbook.yml

we could use vars in playbook just like other type of vars

Var Scope

• global
  • vars in the ansible.cfg
  • env vars
  • from cli
• play
  • var keywords in playbook
  • include_vars keyword
  • default/main.yml or vars/main.yml in role
• host
  • vars defined in the host inventory list
  • remote host system var
  • registered vars

Var Precedence

ekreutz/ansible_variable_precedence.md

from the least to the most important

• role defaults
• inventory file or script group vars
• inventory group_vars/all
• playbook group_vars/all
• inventory group_vars/*
• playbook group_vars/*
• inventory file or script host vars
• inventory host_vars/*
• playbook host_vars/*
• host facts
• play vars
• play vars_prompt
• play vars_files
• role vars (defined in role/vars/main.yml)
• block vars (only for tasks in block)
• task vars (only for the task)
• role (and include_role) params
• include params
• include_vars
• set_facts / registered vars
• extra vars (always win precedence)