A Practical Implementation Sequence

Enterprise problem: A broad observability rollout fails when teams deploy collectors, dashboards, and distributed stores before identity, critical signals, privacy, investigation paths, and ownership are proven for one service.

Whole-course context: The incoming review catalogue identifies anti-patterns and the earlier contracts define components, scale, cost, schema, and security; this day sequences them into reversible delivery phases.

Today’s slice: We move from canonical identity through metrics, logs, traces, collector policy, investigation, alerts, justified scale, profiling, and continuous governance.

End-of-day evidence: A phase ledger for one critical service contains positive and negative probes, entry and exit criteria, rollback, owners, and immutable artifacts.

Still unsolved: The final day will compress the whole course into one reusable behavior-to-action mental model.

A roadmap based on installed products can report progress while customers remain unobservable. These cases measure a complete investigation and a safely governed rollout.

Use case ID	Actor	Customer job	Success outcome	Denial or recovery evidence
D23-UC-01	Service on-call	Investigate one critical customer failure from outcome to owner and runbook	A metric anomaly links to a trace, related logs, deployment, owner, and action within the target time	A broken context link blocks phase exit and rollback restores the last passing instrumentation revision
D23-UC-02	Observability program lead	Expand capabilities only after prerequisites and evidence pass	Each phase has an accountable owner, bounded scope, cost/security guardrails, and observed exit criteria	A premature distributed-backend or profiling phase is denied while the existing service path remains healthy

Phase names alone invite checkbox delivery, so each story names a customer-visible milestone and a negative acceptance condition.

Story ID	Use case IDs	User story	Observable acceptance conditions
D23-US-01	D23-UC-01	As a service on-call, I want one complete investigation path, so that new telemetry shortens a real diagnosis rather than producing disconnected data	Seeded failure is found through rate, errors, and duration, then trace, logs, deployment, owner, and runbook; invalid trace linkage is detected
D23-US-02	D23-UC-02	As a program lead, I want evidence-gated phases, so that scale and cost arrive only with justified requirements	Ledger rejects a phase with unmet prerequisites and records an unaffected positive control plus rollback result

A sequence is useful only when each phase changes an observable capability and can stop safely. These flows begin with a service-selection action and a phase promotion decision.

Flow ID	Use case IDs	Path	Trigger	Numbered steps	Terminal evidence
D23-FLOW-01	D23-UC-01	Happy	Service owner selects a critical customer path for rollout	1. Canonical identity is emitted.<br>2. Critical metrics and structured logs are validated.<br>3. Trace propagation is proven.<br>4. Collector policy protects and routes signals.<br>5. Dashboard, trace, logs, deployment, owner, and runbook form one timed investigation.<br>6. Outcome alert is exercised.	Actor, service/build, schema and policy revisions, expected/observed investigation steps, elapsed time, environment, timestamp, trace ID, alert ID, and run ID
D23-FLOW-02	D23-UC-02	Denied	Lead requests distributed storage before measured scale criteria pass	1. Phase gate reads prerequisites and current requirements.<br>2. Capacity evidence is missing.<br>3. Promotion is denied.<br>4. Current topology receives a fault probe.<br>5. Existing investigation path remains healthy.	Requested phase, missing criterion, denial, current-topology positive control, cost estimate, environment, timestamp, and decision ID

Without an authoritative phase gate, independent teams can skip prerequisites and create incompatible telemetry. The system records evidence and keeps promotion distinct from runtime execution.

Use case ID	Entry point	Responsible services	Authoritative store	Failure evidence
D23-UC-01	Service rollout workspace and investigation runner	Instrumentation CI, collector policy validator, telemetry backends, Grafana, ruler, Alertmanager, ownership catalogue	Phase evidence ledger owned by the observability program	Identity mismatch, missing signal, broken propagation, redaction failure, query/link failure, or notification failure
D23-UC-02	Phase promotion review	Phase gate, requirements registry, cost model, security scanner, topology controller	Rollout programme registry owned by the observability program	Missing prerequisite, unjustified scale, budget breach, privacy failure, rollback failure, or unhealthy positive control

Rollout knowledge disappears when it lives in project slides, so phase criteria, service status, and evidence must be durable and independently reviewable.

Generated-application database: Not created in this slice — rollout state and operational evidence are observability control-plane records.

Record or entity	Store and owner	Primary key	Foreign key or opaque reference	Tenant key	Material constraint	Lifecycle and deletion	Use case IDs
PhaseDefinition	Programme registry, observability program owner	phase_definition_id	None — root versioned phase definition	organization_id	Ordered phase number, prerequisites, exit criteria, rollback, and accountable role are mandatory	Publish immutably, supersede by version, retain through programme audit	D23-UC-01, D23-UC-02
ServicePhaseState	Programme registry, service owner	service_phase_state_id	phase_definition_id local FK and opaque service-catalogue reference	organization_id	One active phase per service/environment; promotion requires all exit evidence	Create on enrolment, advance or roll back by decision, archive on service retirement	D23-UC-01, D23-UC-02
PhaseEvidenceRun	Evidence store, release engineering owner	run_id	service_phase_state_id local FK plus opaque build, trace, alert, and artifact references	organization_id	Actor, scope, prerequisites, expected/observed results, environment, timestamp, and fixture hash are immutable	Retain verdict to programme policy, expire bulky telemetry separately, delete after audit window	D23-UC-01, D23-UC-02

Doing everything at once prevents teams from knowing which change improved or damaged investigations. Each phase below earns the next capability with explicit exit evidence.

Phase	Deliverable	Exit evidence
1. Define identity	Canonical service, environment, region, cluster, version, owner, and tenant fields	Cross-signal identity fixture joins without ad hoc renaming
2. Instrument critical metrics	Request rate, errors, duration; resource utilization, saturation, errors, capacity, and queue depth	Seeded customer impact and pressure are detected with bounded cardinality
3. Establish structured logging	Timestamp, severity, event, identity, trace reference, error category, version, message, privacy class	Required event is queryable; forbidden canary is absent
4. Trace critical paths	Ingress, service calls, database, queues, external providers, model inference, retrieval, and tools where relevant	Parent context survives each chosen boundary; invalid propagation test fails visibly
5. Deploy collector policy	Batching, redaction, enrichment, sampling, routing, authentication, limits, and backpressure	Positive and negative fixtures reach only intended tenant destinations
6. Build one investigation path	Dashboard to metric anomaly to trace to logs to deployment, owner, and runbook	Seeded incident completes within target time with immutable run evidence
7. Build actionable alerting	Page states threatened outcome, owner, first inspection, possible action, and runbook	Seeded sustained outcome breach notifies once; harmless component event does not page
8. Scale storage on requirements	Mimir or distributed Loki/Tempo only for explicit volume, retention, availability, tenancy, central-query, isolation, or regional needs	Existing topology fails a documented objective and candidate passes load/fault/rollback tests
9. Add continuous profiling	Profiles target services and operations located by metrics and traces	Known hot function appears and overhead remains inside budget
10. Govern continuously	Cost and quality by team: series, bytes, sampling, unused artifacts, noisy alerts, query cost, retention	Recurring review removes one low-value cost without losing the seeded incident path

Project momentum can pressure teams to promote on partial evidence, so use the same denial-capable gate at every phase.

1. State the customer milestone, incoming artifact, boundary, owner, and material deferred risk.
2. Pin schema, policy, topology, fixture, and service build revisions.
3. Run the happy path and at least one denied, failed, or recovery path.
4. Record actor, resource, scope, precondition, expected, observed, environment, timestamp, and immutable IDs.
5. Re-run the previous phase’s positive control to detect regression.
6. Falsify promotion if any criterion lacks observed evidence, if rollback fails, or if cost/privacy guardrails regress.
7. Promote one phase, observe, and retain the last passing revision for recovery.

The fastest reliable programme builds one complete evidence-to-action path before broad coverage or distributed scale.

• Identity comes first because every later correlation and ownership decision depends on it.
• Metrics, structured logs, and critical-path traces precede platform-wide rollout.
• Collector policy and one complete investigation path precede dashboard proliferation.
• Scale and profiling are earned by measured needs; cost and quality governance never ends.

A phase is complete only when it produces customer-visible and falsifiable evidence.

• [ ] One critical service has canonical cross-signal identity.
• [ ] Rate, errors, duration, pressure, structured logs, and context propagation are proven.
• [ ] Privacy, tenant routing, limits, and backpressure have negative tests.
• [ ] One seeded incident reaches deployment, owner, runbook, and action.
• [ ] Storage scale is tied to a failed explicit requirement and a passing candidate.

The sequence uses current collector and signal conventions, checked against official primary documentation.

• Grafana Alloy collection, processing, and deployment patterns
• OpenTelemetry Collector processors
• Prometheus instrumentation practices