Per the Wikimedia Services Policy, in order to launch the function orchestrator and evaluator services, they need an operational runbook: https://wikitech.wikimedia.org/wiki/Wikifunctions/Runbook .
Although this is not needed until the launch, it'd be good to start a document early, so there's a natural place to write things down.
Existing runbooks on Wikitech for examples. These seem to vary quite a lot in quality.