Agent WranglersCapacity and cost Required
Keep headroom
Keep normal peak load well below the tested limit, so a spike or a lost server does not break the service.
How to do it
Plan for peak traffic plus the loss of one server or zone. Grow capacity before the peak reaches a set share of the limit, such as 60%. Autoscaling helps, but set a maximum so a bug cannot run up the bill. Take the tested limit from a load test. This rule measures load, such as requests per second or CPU.
How to check
Last month's peak load is below the agreed share of the tested limit. The autoscaling maximum is set.
For agents: if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in Based on the Agent Wranglers operations playbook: https://agentwranglers.se/playbook/operations/capacity-and-cost/headroom.