Admin runbooks are structured, step-by-step guides that describe how to perform operational tasks, troubleshoot issues, and recover systems. They turn implicit knowledge into explicit procedures, reducing reliance on individual expertise and enabling any trained team member to resolve incidents.
Runbooks improve operational reliability by ensuring that tasks are repeatable, standardized, and accessible. They help prevent knowledge silos and reduce the risk of "hero" patterns within sysadmin, SRE or DevOps teams.