Comparison
Error budget policyvsRisk appetite
Error budget policy
the budget was spent in the first week of the quarter, and feature work stopped until reliability caught up.
The agreement, made in advance, about what happens when the error budget implied by an objective is exhausted. Without it an error budget is a dashboard; with it, it is a pre-negotiated answer to the reliability-versus-features argument that would otherwise be had under pressure and won by whoever is loudest. The policy is the product — the number was never the point.
Full entry →Risk appetite
the same deploy process guards the marketing site and the payments ledger, and everyone is annoyed.
How much risk this system, at this moment, is willing to accept — which is a business answer rather than an engineering one. It varies by system and by season: a pre-revenue product and a regulated ledger should not have the same change process, and a retailer's appetite in November is not its appetite in March. Naming it converts a stalled safety argument into a question for the person who actually owns the consequences.
Full entry →