Ansible Key Notes & Gotchas

Variable Precedence (22 levels — highest wins)

1.Extra vars (-e) — always wins

2.Task vars (set_fact, register)

3.Block vars

4.Role params

5.Include vars

6.Play vars_files

7.Play vars

8.Host facts

9.host_vars files

10.group_vars/all

11.Role defaults — lowest

Idempotency Rules

•Use apt/yum NOT shell: apt install — modules are idempotent, shell is not

•Use copy with content= NOT shell: echo > file

•Use lineinfile NOT shell: sed

•Use template NOT shell: cat > file

Performance Tips

•Enable pipelining in ansible.cfg: pipelining = True (10-30% faster)

•Increase forks: forks = 20 (default 5)

•Use gather_facts: false when you don't need facts

•Use async for long-running tasks

Security Best Practices

•Never store plain text passwords in playbooks or inventory

•Use ansible-vault for all secrets

•Use become only when necessary (avoid become: yes globally)

•Restrict SSH key permissions: chmod 600 ~/.ssh/id_rsa

•Use dedicated service accounts, not personal accounts

Common Gotchas

•command/shell modules are NOT idempotent — they always run

•Handlers run at end of play, not immediately when notified

•loop replaces deprecated with_items in Ansible 2.5+

•Variables in quotes need special handling: "{ variable }"

•become: yes is sudo — need NOPASSWD in sudoers for automation

Quick Reference — Ansible

Key Points for Revision

•Review the overview section for core architecture and fundamentals

•Practice commands/configurations from the cheatsheet section

•Use interview Q&A for active recall before exams or interviews

•Cross-reference with related tools in the devops academy

Practice Approach

1.Read the overview to understand what and why

2.Work through fundamentals for how

3.Attempt hands-on labs or configurations

4.Test yourself with interview questions

5.Keep cheatsheet accessible for quick reference during work

Further Learning

Connect this topic to the broader devops ecosystem.

Each tool in this academy is designed to work with others —

understanding the integration points is what separates intermediate from senior practitioners.

Ansible — Notes