ERROR! 'include_vars' is not a valid attribute for a Play

hawksbill

This is as the error says, you are using the wrong file when running ansible-playbook.

$ ansible-playbook -i ./ec2.py playbooks/myplay.yml --limit 10.50.20.34 --private-key=./ansible_mgmt.pem.txt
ERROR! 'include_vars' is not a valid attribute for a Play

The error appears to have been in '/home/ansible/iac/ansible/playbooks/create_users.yml': line 2, column 3, but may
be elsewhere in the file depending on the exact syntax problem.

The offending line appears to be:

---
- name: Include vars
  ^ here

A playbook will have the hosts entry in it, it is likely there is a top level playbook main.yml or similar which imports other tasks.