Ansible guidelines

Variables are used extensively in Ansible. But one of the frustrating things about Ansible is that it offers too much freedom. This has both advantages and disadvantages. The disadvantage is complexity along with high responsibility, and the advantage is flexibility. Let's recap and organize what we know about Ansible variables.

Variables can be divided into two categories:

• ( "Filesystem").

  
  
  
  
  

• ( "Code").

  
  
  
  
  

, , .

Filesystem- Code-. ? .

1.

(Inventory



, group_vars



, host_vars



, role/defaults/main.yml



role/vars/main.yml



). "" . — , . "" , , . , , vars



, block



. :

- name: Variables scope
  hosts: localhost
  connection: local
  vars:
    MY_VAR: "I am global var"
  tasks:
    - block:
      - name: Print variable inside the block.
        debug:
          var: MY_VAR
        vars:
          MY_VAR: "I am local var"
- name: Print variable outside the block.
  debug:
    var: MY_VAR

      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

PLAY [Variables scope]
 TASK [Gathering Facts]
 ok: [localhost]
 TASK [Print variable inside the block.]
 ok: [localhost] => {
 "MY_VAR": "I am local var"
 }
 TASK [Print variable outside the block.]
 ok: [localhost] => {
 "MY_VAR": "I am global var"
 }

      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

, . . defaults/main.yml



. , . , , .

2. README

, , , README. ansible-galaxy init , README. , , README , . . , git, wiki-. , , wiki-. .

3.

"" ( ) . . , . , , port? , , . : — consul. — url, — consul_url.

4.

Ansible . , . : , .

:

# No name/description
- copy: dest=/tmp/text.txt, content="bla-bla"
- name: Print variable global var.
 debug:
   var: MY_VAR
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

TASK [copy]
changed: [localhost]
TASK [Print variable global var.] *
ok: [localhost] => {
"MY_VAR": "I am global var"
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

5. DRY (Don't Repeat Yourself)

Ansible . , Ansible , DRY (Don't Repeat Yourself). . , .

:

: (include/import)tasks



, (include/import)role



. ? , uri API-. , POST-. 10 uri , - . .

: send_post.yml

- name: .::::::::::::. [ Sent POST request ] .::::::::::::.
 uri:
   url: "{{ URL }}"
   method: POST
   status_code: 200
   body: "{{ BODY_VAR | to_nice_json }}"
   body_format: json
   validate_certs: yes
   client_cert: tls.crt
   client_key: tls.key
   register: return_values
 when: BODY_VAR is defined

      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

.

- name: Bla-bla
   include_tasks: send_post.yml
   vars:
       URL: "{{ main_url }}/{{ item }}"
       BODY_VAR: "{{ item }}"
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

URL BODY_VAR — .

6. (block)

block.  

, . block try / catch .

- block:
   ...
  rescue:
   ...
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

block/rescue



— ignore_errors



. , . , , - , . , .

 - block:
   - name: .....
   - name: .....
   - name: .....
   always:
     file:
       path: /tmp/xxxx
       state: absent
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

7. command shell

command



shell



, . , . :

• when
  
  
  
  

  
  
  
  
  

• creates
  
  
  
  ( , ).

  
  
  
  
  

• removes
  
  
  
  ( , ).

  
  
  
  
  

• changedwhen
  
  
  
  .

  
  
  
  
  

, command



shell



.

8.

. , . . , README. . . , always



, never



—  .

skip_ansible_lint



— ansible-lint



.

9.

. become



no



, . become



. :

---
 - hosts: wordpress
    become: no
     ...
    role:
      - role: wordpress

tasks/main.yml
---
- name: Install mysql-server pkg
  apt:
    name: mysql-server
    state: present
  become: yes
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

10. YAML-

YAML . :

YAML

- name: Install apache httpd
  apt:
    name: apache2
    state: present
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

- name: Install apache httpd
  apt: pkg=apache2 state=pesent
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

11. gitignore

.gitignore



, git-. .gitignore



:

*.retry
*/__pycache__
*.pyc
*.log
### IntelliJ IDEA ###
.idea
*.iws
*.iml
*.ipr
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

12. Ansible

ansible  

13.

, .

14. Ansible-

Ansible. , molecule. . , .

15.

Ansible? , git , . , . . — .

requirements.yaml:

---
- src: git@gitlab.company.com:mygroup/ansible.git
 scm: git
 version: "0.1"
...
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

:

• src

  
  
  
  
  

• scm

  
  
  
  
  

• version

  
  
  
  
  

• name

  
  
  
  
  

---

 «DevOps ».

- : «Prometheus: ». Prometheus , , .