Add Grafana Tempo distributed tracing with demo application

- Deploy Grafana Tempo in monolithic mode for distributed tracing
- Configure Tempo with OTLP receivers (gRPC:4317, HTTP:4318)
- Set up 10Gi filesystem storage with 7-day retention
- Integrate Tempo datasource in Grafana with traces-to-logs and traces-to-metrics correlation

- Update Grafana Alloy to collect and forward traces
- Add OTLP receiver configuration to alloy-values.yaml
- Configure batch processor for efficient trace forwarding to Tempo
- Patch Alloy service to expose OTLP ports 4317/4318

- Create demo tracing application (frontend, middleware, backend)
- Implement three-tier Python Flask application with OpenTelemetry instrumentation
- Auto-instrument with OpenTelemetry for Flask and requests libraries
- Push Docker images to private registry (registry.lan.buetow.org:30001)
- Deploy via Helm chart with Traefik ingress at tracing-demo.f3s.buetow.org

- Update Grafana configuration in prometheus/persistence-values.yaml
- Add Tempo to additionalDataSources for automatic provisioning

Files added:
- tempo/values.yaml: Tempo Helm chart configuration
- tempo/persistent-volumes.yaml: Storage configuration (10Gi PV/PVC)
- tempo/datasource-configmap.yaml: Grafana datasource with correlations
- tempo/Justfile: Installation automation
- tempo/README.md: Documentation

- tracing-demo/docker/frontend/: Python Flask frontend with OTel
- tracing-demo/docker/middleware/: Python Flask middleware with OTel
- tracing-demo/docker/backend/: Python Flask backend with OTel
- tracing-demo/helm-chart/: Kubernetes deployments, services, ingress
- tracing-demo/docker-image-Justfile: Docker build/push automation
- tracing-demo/Justfile: Helm deployment automation
- tracing-demo/README.md: Documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 29 insertions, 1 deletions

diff --git a/f3s/prometheus/persistence-values.yaml b/f3s/prometheus/persistence-values.yaml
index b5e13e4..7e115a9 100644
--- a/f3s/prometheus/persistence-values.yaml
+++ b/f3s/prometheus/persistence-values.yaml
@@ -55,4 +55,32 @@ grafana:
   podSecurityContext:
     fsGroup: 911
     runAsUser: 911
-    runAsGroup: 911
\ No newline at end of file
+    runAsGroup: 911
+
+  additionalDataSources:
+    - name: Tempo
+      type: tempo
+      uid: tempo
+      url: http://tempo.monitoring.svc.cluster.local:3200
+      access: proxy
+      isDefault: false
+      editable: true
+      jsonData:
+        httpMethod: GET
+        tracesToLogsV2:
+          datasourceUid: 'loki'
+          spanStartTimeShift: '-1h'
+          spanEndTimeShift: '1h'
+          filterByTraceID: false
+          filterBySpanID: false
+          tags: ['cluster', 'namespace', 'pod', 'app']
+        tracesToMetrics:
+          datasourceUid: 'prometheus'
+        serviceMap:
+          datasourceUid: 'prometheus'
+        nodeGraph:
+          enabled: true
+        search:
+          hide: false
+        lokiSearch:
+          datasourceUid: 'loki'
\ No newline at end of file