Composing SLOs across dependencies
On This Lesson 4 topics
This lesson is planned. The outline below lists the topics it will cover. The full lesson has not been published yet.
In this lesson
avoid promising more nines than the dependencies allow.
Planned topics
- For hard serial dependencies, availabilities multiply: three components at 99.9% give about 99.7%.
- Redundancy, caching, retries with limits, and graceful degradation raise the composite; map each hard dependency and ask what the order flow does without it.
- Ask each dependency owner for an SLO; if there is none, treat it as unknown risk.
- Decide where to degrade (accept the order, charge later) rather than fail.
Draft outline details
Demonstration
Dependency graph for the order journey (gateway, orders, inventory, payment provider, database) with each SLO, which are hard or soft, and the computed ceiling versus the 99.95% target.
Check your understanding
Two serial hard dependencies at 99.9% each give roughly what availability?
Show answer
About 99.8%.
Practice
Apply this lesson with the module's lab, exercises and quiz.
Marking a lesson complete is optional and you can undo it any time. Your progress stays in this browser.