Nines per service

Sets one availability target per service in services/<id>.yml. The target follows from three things: what users lose when the service is down, the tier, and the serial dependencies. A service fails when one of its serial dependencies fails, so its availability cannot exceed the product of their availabilities. The skill computes that ceiling, shows the allowed downtime for the candidate targets, and writes the chosen target into the catalogue after the owner agrees.

Inputs

• Service (required): the catalogue id. Without an entry, start one from services/_template.yml.
• User impact: who notices an outage, how fast, and what an hour down costs them.
• Tier: from the catalogue, or decided now.
• Dependencies: the serial ones (depends_on) and the ones the service survives (soft_depends_on). For an external dependency, the availability the provider commits to. Check before use: each provider's commitment, in its current SLA document.
• Measured availability: the last 30 and 90 days, if a metric or probe exists.

Allowed downtime

Allowed downtime = (1 - target) × window, with the target as a fraction. Windows: 30 days (43,200 min), a quarter of 90 days (129,600 min), a year of 365 days (525,600 min).