Best practices for writing better ansible playbooks

Some of the best practices for writing the clean and scalable ansible playbooks:

1. Maintain all ansible code in git.
2. Maintain the standard directory structure. Here is the reference: https://github.com/Indu-sharma/learningansible
3. Use requirements.txt for python dependencies management and requirements.yml for ansible-galaxy modules/roles.
4. Configure ansible_stdout_callback, log file path, forks in ansible.cfg.
5. Always use -check mode for ansible playbooks for the dry run. 
6. Verify all your variables in advance with -m setup.
7. Use ansible-galaxy init for your creating your roles directory/files structures.
8. Within a role playbook, follow the sequence in the start
• Use assert to check that requirements are met
• Install packages
• Use Validate for Template config files 
• Trigger handlers when config files have been changed  
9. Avoid using shell/command modules if possible; they are skipped in -check mode.
10. Avoid using set_facts; they are not visible when using -m setup mode. Also, variables are not while using --start-at option.
11. Use Tags as much as possibles.
12. Don't hide changes(when using --diff/-check )
13. Don't suppress failures. 
14. Ensure Idem-potency always. 
15. Don't hard code any variables in playbooks.
16. Use Dynamic Inventory wherever possible
17. Use strategy as Debug in the playbooks.
18. Use Mitogen or Pipe-lining to speed up the playbooks run time. 
19. Use Molecule module to test the playbooks.