Calculation and operational limits

An interval sample represents good and total event counts over (T-step, T], not a cumulative counter or arbitrary rate. Timestamps are aligned to UTC steps.

• Counts must be finite and nonnegative, with good no greater than total. Reimporting a timestamp replaces its counts.
• For observed traffic, reliability is sum(good) / sum(total).
  • Error budget uses observed total and 1-target; burn rate divides observed error ratio by 1-target. Missing data remains unknown.
  • Zero traffic is not reported as 100% success.
  • Coverage and negative remaining budgets remain visible.
  • Targets are fractions strictly between zero and one.
• Rolling windows use (at-window, at], with up to 31 days and bounded retention.
  • Two rolling windows of interval samples are retained.
  • Current history uses the current SLO configuration; an explicit archived revision uses its original definition and retained evidence.
  • Increasing a window does not restore data already pruned.
  • Measurement/source changes keep the SLO name, archive the previous revision and start fresh active measurement coverage.
  • All definition edits require the expected revision. See SLO editing and revision history.
• Provider-window measurements evaluate configured selectors over complete windows instead of summing independently extrapolated short-window increases. Prometheus increase() remains a scrape-based estimate.
  • Sparse traffic, missed instrumentation, resets between scrapes, provider retention and long-range query cost remain limits.
  • A declared measurement or a model's recommendation does not prove end-to-end journey success.
• Each configured burn policy compares both short and long windows against the threshold, minimum coverage and optional minEvents count. Only committed SLOs emit burn alerts.
  • Other lifecycles retain measurements and recording rules. See lifecycle and eligibility. Pending duration requires consecutive observations.
  • Missing data resets pending and does not resolve a firing alert.
  • Historical evaluations do not emit historical notifications.
  • Rule generation, provider acceptance, actual rule evaluation and observed SLO health are separate states.
• Review rules plan and its destination before rules apply --expected-digest ....
  • Prometheus file output, Prometheus Operator resources and Mimir ruler datasets have different ownership and loading requirements.
  • Deploying a YAML file does not prove a Prometheus server selected it.
  • Do not let both the platform and Kubernetes operator own the same rule group.
• The MVP targets one collecting server process.
  • Reads and transactional writes are bounded, but high-cardinality scale, distributed scheduling, queued large backfills and HA operation are not release claims. Reviewed SLO archival and deletion retain audit receipts and require owned-rule cleanup.
  • Calendar windows and silences are not offered.
  • Up to eight named severity policies have independent alert lifecycles; notification grouping and inhibition remain external Alertmanager configuration.
  • PostgreSQL is required for durable normal deployments.
  • Back up storage and validate restore procedures before retaining important data.
• CUJ health rolls up explicit required links conservatively; advisory links remain visible.
  • New or insufficiently observed objectives stay unknown.
  • CUJ run verdicts and inferred dependency impact do not alter SLO arithmetic.

Read SLO charts

• The Performance tab shares one time range across SLI/target, remaining error budget and burn-rate panels.
  • Use Time range for relative presets or an absolute start/end, then Apply range.
  • Date inputs, axes and chart inspection use UTC.
  • Editing an absolute range does not query the server until applied; Cancel preserves the existing range.
  • Absolute bounds align inward to complete measurement intervals.
  • Future or invalid ranges are rejected, and the server enforces retention and its latest completed evaluation cutoff.
  • History is retained for at most two SLO windows; data availability can be shorter.
• Panels resize with their container and stack when two columns would crowd the plots.
  • Hover, tap or focus a chart and use Left/Right, Home or End to inspect the same interval across panels.
  • Missing or zero-traffic intervals remain gaps; partial rolling coverage is shown separately and does not establish full-window compliance.
  • Burn threshold crossings and recorded alert transitions remain separate from measured attainment and notification delivery.
• Manage Prometheus and Mimir under Telemetry connections.
  • Existing /data-sources bookmarks remain accepted; new navigation uses /telemetry-connections.
  • This is a portal terminology change; API endpoints, CLI commands and YAML source fields retain their contracts.