Composite SLOs

⛭ Weighing error budget calculations

The calculations are not weighted.

⛭ Burn rate representation in terms of composite SLOs

It’s representing the results of the calculations as described in Composite SLOs and error budget calculations.
The logic of those calculations is the same for composite SLOs as for regular (standard) objectives and SLOs. Read more about error budget burn rate. The only differences in the calculations are as follows:

• SLI comes from the Nobl9 app, not from the agent or direct. Possible SLIs are:
  • burn rate for Occurrences (the same as on the charts on SLO details)
  • good or bad minute for Time Slices—these values are not presented on any chart; they are used to calculate burn rates and error budgets
• burnRateCondition used for determining if the error budget will burn

⛭ Composite SLO with one objective vs. more objectives with burn rate greater than the burn rate condition

One objective satisfying burn rate condition causes the budget for a composite SLO to burn at the same rate.

⛭ Changing SLOs to composite: impact on objective calculations

Upon turning SLOs into composite SLOs, objective calculations are not impacted. Also, it doesn't cause any loss of results or chart data.
However, modifying a burn rate condition in the composite SLO has an impact: it resets calculations similar to a normal objective upon the objective value change.

⛭ Objective's historical data in composite SLO charts calculation

Nobl9 does not calculate data for composite SLOs charts using objective's historical data. Creating composite SLO is similar to creating a new objective—only new incoming data is used during calculations.