Ansible playbook 没有从库存 group_vars 中获取值

Question

I have got a simple playbook:

- hosts: all
  serial: 1
  order: "{{ run_order }}"
  gather_facts: false
  tasks:
    - ping:
      register: resultt

My inventory tree:

.
├── group_vars
│   └── g1
│       └── values.yml
├── host_vars
└── inv

inv file:

[g1:children]
m1
m2

[g2:children]
m3
m4

[m1]
192.168.0.60

[m2]
192.168.0.61

[m3]
192.168.0.62

[m4]
192.168.0.63 

group_vars/g1/values.yml:

---
run_order: 'reverse_sorted'

When I try to run playbook:

ansible-playbook -i inv-test/inv --limit='g1' my-playbook.yml

I get the error:

ERROR! The field 'order' has an invalid value, which includes an undefined variable. The error was: 'run_order' is undefined

The error appears to be in '/home/mk/throttle': line 1, column 3, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:


- hosts: all
  ^ here

Although the output from ansible-inventory -i inv --graph --vars is correct

Why ansible doesn't parse vars from inventory groups_vars? Ansible version 2.10.15

Answer 1

The problem is that you want to use a host variable in the scope of a play. See Scoping variables . It's possible if you create such a host variable first. Then you can use hostvars to reference the host variable. For example, given the simplified inventory

shell> cat hosts
[g1]
host_01
host_02

and the group_vars

shell> cat group_vars/g1.yml 
run_order: 'reverse_sorted'

The playbook

shell> cat pb.yml
- hosts: all
  gather_facts: false
  tasks:
    - debug:
        var: run_order

gives (abridged)

shell> ansible-playbook -i hosts pb.yml 

ok: [host_01] => 
  run_order: reverse_sorted
ok: [host_02] => 
  run_order: reverse_sorted

But, the playbook below

shell> cat pb.yml
- hosts: all
  gather_facts: false
  order: "{{ run_order }}"
  tasks:
    - debug:
        var: run_order

fails because the variable run_order is not defined in the scope of the play

ERROR! The field 'order' has an invalid value, which includes an undefined variable. The error was: 'run_order' is undefined

The (awkward) solution is to create the hostvars in the first play and use it in the second play. For example, the second play in the playbook below is executed in the reverse order

shell> cat pb.yml
- hosts: all
  gather_facts: false
  tasks:
    - debug:
        var: run_order

- hosts: all
  gather_facts: false
  serial: 1
  order: "{{ hostvars.host_01.run_order }}"
  tasks:
    - debug:
        var: run_order

gives

shell> ansible-playbook -i hosts pb.yml 

PLAY [all] ***********************************************************************************

TASK [debug] *********************************************************************************
ok: [host_01] => 
  run_order: reverse_sorted
ok: [host_02] => 
  run_order: reverse_sorted

PLAY [all] ***********************************************************************************

TASK [debug] *********************************************************************************
ok: [host_02] => 
  run_order: reverse_sorted

PLAY [all] ***********************************************************************************

TASK [debug] *********************************************************************************
ok: [host_01] => 
  run_order: reverse_sorted