YAML and Variable Errors¶

Why This Exists¶

These two error categories both surface before a task ever reaches a host — they're the fastest to fix, once you know where to look, and the most common first-week source of "the playbook does nothing" confusion.

What It Will Cover¶

• Reading a YAML parser's line/column error precisely — it often points slightly after the real mistake (a missing colon or bad indentation one line earlier is a common false trail)
• ansible-playbook --syntax-check as the fastest zero-risk first check on any edited playbook
• 'dict object' has no attribute 'X' — usually a typo in a variable/dictionary key, or a variable that's a different shape than assumed; pair with ansible.builtin.debug: var= on the parent object to inspect its real shape
• 'X' is undefined — tracing which of the variable sources was expected to provide it, using ansible-inventory --host <name> per Variable Precedence
• The YAML "Norway problem" (no/yes/country codes parsing as booleans) surfacing as a confusing type error deep in a task, not at parse time

Interview Questions¶

• A task fails with 'X' is undefined — what's your process for finding where it should have come from?
• Why does a YAML syntax error sometimes point to the wrong line?

Next¶

Continue to Module and Execution Errors.