The budget can also be based on an SLA. A certain amount of instability is expected each month, which is considered a budget. Each roll-out uses some of the budget, as do instability-related bugs. Developers can maximize the number of roll-outs that can be done each month by dedicating effort to improve the code that causes this instability. This creates a positive feedback loop. An example of this is Google’s Error Budgets, which are more fully explained in Section 19.4.
Erm, think you mean negative feedback loop. ;) again, let's achieve more precision in this book
That said, this error budget idea intrigues.
