[demo] Update demo docs to match opentelemetry-demo main (removed/added services, k6, collector renames)

[mwimpelberg28]

Summary

The OpenTelemetry Demo documentation under content/en/docs/demo/ has drifted from the
current opentelemetry-demo main
branch. This is a meta/tracking issue enumerating each needed update, grouped by theme.
File paths are relative to content/en/docs/demo/. Linked PRs are in opentelemetry-demo.

Happy to split any group into its own issue/PR — this is a checklist to coordinate the work.

1. Remove deleted services (product-reviews, llm) — — #10963

product-reviews and llm were removed from the demo
(open-telemetry/opentelemetry-demo#3568, open-telemetry/opentelemetry-demo#3587,
open-telemetry/opentelemetry-demo#3599) but the docs still reference them.

• Delete services/product-reviews.md (entire page is for the removed service)
• architecture.md — remove llm and product-reviews nodes and all their edges from the graph TD service diagram
• _index.md — remove Product Reviews from the Python row of the Language Feature Reference table, and from the Service Documentation list
• services/_index.md — remove the product-reviews table row
• feature-flags/_index.md — remove the llmInaccurateResponse and llmRateLimitError flags (mock LLM service is gone)
• telemetry-features/metric-coverage.md, trace-coverage.md, log-coverage.md — remove the Product Reviews rows
• telemetry-features/manual-span-attributes.md — remove the "Product Reviews" section and app.product_reviews.* attributes
• sample-configurations/tail-sampling-service-criticality.md — remove product-reviews from the medium-criticality tier

2. Add docs for new services — see #10574

New services added but undocumented: Agent/MCP/Chatbot
(open-telemetry/opentelemetry-demo#3455), OpAMP server
(open-telemetry/opentelemetry-demo#3566), telemetry-docs
(open-telemetry/opentelemetry-demo#2794).

• Create services/agent.md — Python 3.14, FastAPI + Uvicorn, LangChain/LangGraph ReAct agent, POST /prompt, port 8010, instrumented with the Traceloop SDK + OTLP; built-in tools vs MCP tool mode
• Create services/chatbot.md — Python 3.14, Gradio chat UI, forwards to the agent, port 7860, served at /chatbot/, OTLP/gRPC traces
• Create services/mcp.md — Python 3.14, FastMCP server exposing shop tools over the Model Context Protocol at /mcp, port 8011, Traceloop SDK + httpx instrumentation
• Create services/opamp-server.md — Go reference OpAMP server (opamp-go); Collector opampextension reports health/config; UI at /opamp/
• Create services/telemetry-docs.md — Weaver + MkDocs + nginx-otel; hosts the telemetry-schema docs at /telemetry/, port 8000
• architecture.md — add agent, mcp, chatbot nodes and edges (frontend-proxy → chatbot → agent → mcp → frontend, agent → product-catalog, plus the LLM dependency); optionally add opamp-server and telemetry-docs
• _index.md — add the new Python services to the Language Feature Reference table and the Service Documentation list
• services/_index.md — add table rows for the 5 new services

3. Load generator: Locust → k6 — done in #10969

The load generator was rewritten from Locust to k6
(open-telemetry/opentelemetry-demo#3564).

• Rewrite services/load-generator.md for k6 + the xk6-otel extension — script.js structure, weighted traffic mix, flagd-driven VUs (loadGeneratorTraffic/loadGeneratorVUs), optional headless-browser scenario, and K6_OTEL_* / LOAD_GENERATOR_VUS env vars. Update cSpell:ignore (drop locustfile/urllib)
• architecture.md — intro prose "a load generator which uses Locust" → k6
• services/_index.md — load-generator language Python/Locust → JavaScript/k6
• telemetry-features/_index.md — replace Locust references with k6; note k6 has no proxied web UI
• screenshots/index.md — remove or replace the Locust "Load Generator UI" section/image (k6 has no web UI)

4. Collector exporter renames (Collector v0.145.0)

OTLP exporters were renamed (otlp → otlp_grpc/jaeger, otlphttp/prometheus →
otlp_http/prometheus) and span metrics is now the span_metrics connector
(open-telemetry/opentelemetry-demo#2942).

• docker-deployment.md — in the "bring your own backend" snippet, spanmetrics → span_metrics (pipeline + note); update the collector-config description from merging "two files" to the current four-file layering (otelcol-config.yml + -full + -observability + -extras)
• kubernetes-deployment.md — same spanmetrics → span_metrics in the BYO-backend snippet and note
• sample-configurations/tail-sampling-service-criticality.md — exporters: [otlp, debug, spanmetrics] → [otlp_grpc/jaeger, debug, span_metrics]

5. docker-deployment.md — broken/outdated commands

Compose files are now compose.*.yaml; several referenced files/targets no longer exist.

• Minimal mode: docker compose -f docker-compose.minimal.yml ... → the layered compose.yaml + compose.observability.yaml + compose.extras.yaml (make start-minimal)
• Full demo: clarify that a bare docker compose up loads only core compose.yaml; make start layers compose.full.yaml + compose.observability.yaml + compose.extras.yaml
• Minimal-mode exclusion list: drop flagd-ui (now in core compose.yaml); excluded set is accounting, fraud-detection, kafka
• Trace-based testing section: make run-tracetesting, docker-compose-tests.yml, and the traceBasedTests service no longer exist (now compose.tests.yaml with frontendTests); Tracetest UI appears removed — remove or update
• Add the agent/AI stack (make start-agentic / compose.agent.yaml, Chatbot UI at /chatbot/) and the profiling stack (make start-profiling / compose.profiling.yaml, /profiles/); add the telemetry-docs URL /telemetry/ to the verify-URLs list

6. Additional drift found

• feature-flags/_index.md — flag names largely mismatch current src/flagd/demo.flagd.json (e.g. adServiceFailure→adFailure, recommendationServiceCacheFailure→recommendationCacheFailure, paymentServiceFailure→paymentFailure, adServiceManualGc→adManualGc, adServiceHighCpu→adHighCpu, cartServiceFailure→cartFailure); add loadGeneratorTraffic/loadGeneratorVUs; remove emailMemoryLeak/loadgeneratorFloodHomepage
• telemetry-features/ coverage matrices (metric/trace/log) — add rows for agent, chatbot, mcp (and optionally opamp-server, telemetry-docs)
• services/_index.md — add rows for image-provider, kafka, frontend-proxy (they have doc pages but no table row)
• Document the KAFKA_TOPIC env var (default orders, used by checkout/accounting/fraud-detection) — Add KAFKA_TOPIC environment variable opentelemetry-demo#3665

---

Not doc-relevant (code-only fixes, listed for completeness): checkout nanos divisor,
currency VERSION/IPV6_ENABLED guards, react-native device.id, flagd-ui Tailwind/LiveView
fixes. No docs changes needed.

[mwimpelberg28]

Group 1 (remove product-reviews and llm) is addressed by #10963. Checklist items above updated.

[mwimpelberg28]

Group 2 (docs for the new services: agent, chatbot, mcp, opamp-server, telemetry-docs) is addressed by #10964, which is stacked on #10963. Note: opamp-server and telemetry-docs were intentionally left out of the service request-flow diagram (consistent with other infra services like Grafana/Jaeger).

[mwimpelberg28]

Group 3 (load generator Locust → k6) is addressed by #10969.