Runbook
A practical DevOps definition, with an example you can use.
A documented procedure for a recurring operational task or a known failure scenario.
An example you can picture
A high-error-rate runbook names the affected service, shows read-only checks, identifies escalation contacts, and describes how to verify recovery.
The distinction that matters
A runbook is useful only when its steps and assumptions still match the system. Test it and record when it was last reviewed.
Put it into practice
Write a procedure for one failure you have actually reproduced in a lab. Include symptoms, read-only checks, escalation conditions, recovery steps, and the test that proves the service is usable again.
Connect the ideas: logs and rollback. For the bigger picture, read the related learning guide.
Reference
Read the primary documentation for the underlying concept and further detail.