Comparison
Change failure ratevsError budget policy
Change failure rate
one deploy in six needed a fix or a rollback, and nobody had counted until someone asked.
The proportion of deployments causing a degradation that requires remediation. It is the stability half of the DORA pair, and it exists to catch the obvious objection to shipping frequently. A low rate combined with low frequency usually means the team is not shipping rather than that it is careful, which is why the four numbers are only meaningful together.
Full entry →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 →