How should an include playbook be different from a standalone one? - ansible

Question

I have two playbooks which are launched against a remote host (10.233.84.58). When launched standalone (ansible-playbook -i inventory.txt playbook.yml) they work fine.
The first playbook includes the second one, which is identical, except obviously for the include:
---
- hosts: all
tasks:
- debug: msg="hello form playbook1"
# up to now the content is identical between playbook1.yaml and playbook2.yaml
# without the next line the playbook runs fine
- include: playbook2.yml
When I run playbook1.yml:
# ansible-playbook -i inventory.txt playbook1.yml (master✱)
PLAY [all] *********************************************************************
TASK [setup] *******************************************************************
ok: [10.233.84.58]
TASK [debug] *******************************************************************
ok: [10.233.84.58] => {
"msg": "hello form playbook1"
}
TASK [include] *****************************************************************
fatal: [10.233.84.58]: FAILED! => {"failed": true, "reason": "no action detected in task. This often indicates a misspelled module name, or incorrect module path.\n\nThe error appears to have been in '/root/tests/playbook2.yml': line 2, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n---\n- hosts: all\n ^ here\n\n\nThe error appears to have been in '/root/tests/playbook2.yml': line 2, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n---\n- hosts: all\n ^ here\n"}
NO MORE HOSTS LEFT *************************************************************
to retry, use: --limit #playbook1.retry
PLAY RECAP *********************************************************************
10.233.84.58 : ok=2 changed=0 unreachable=0 failed=1
I extracted the "reason" from the error message above and made it more readable:
no action detected in task. This often indicates a misspelled module name, or incorrect module path.
The error appears to have been in '/root/tests/playbook2.yml': line 2, column 3, but may
be elsewhere in the file depending on the exact syntax problem.
The offending line appears to be:
---
- hosts: all
^ here
How should an include playbook be different from a standalone one?

Answer 1

There are two types of include. You can include playbook or list of tasks.
---
- hosts: all
tasks:
- include: list_of_tasks.yml
- include: complete_playbook.yml
In your example you try to include playbook2.yml as a list of tasks.
Move include on the same indent as - hosts and you'll be good.