Declarative Grafana / Prometheus / Loki / Tempo observability stack

Deploys the whole stack into the observability namespace of the local
cluster with Kustomize alone — no helm install, no dashboard created by
hand in the UI. The Makefile carries every command: deploy, dashboards,
diagnostics, PVC flush, teardown.

Dashboards are files, never UI objects. Each carries a stable uid, which
is what keeps URLs, cross-links and alerts alive across redeployments, and
references datasources by stable uid rather than by name. The dashboard
ConfigMap is generated without a name-suffix hash so applying it updates
it in place and Grafana reloads without a restart, while the provisioning
ConfigMaps keep their hash precisely so that a change there does force one.

Prometheus scrapes the kubelet /metrics/resource endpoint rather than
/metrics/cadvisor: on this cluster cadvisor exposes machine_* series only
and no container_* at all, which would leave every CPU and memory panel
empty.

Alloy ships every pod's logs to Loki through the Kubernetes API, so no
/var/log mount is needed. Tempo's metrics_generator feeds span metrics and
the service graph back into Prometheus, and the datasources are wired so a
log line's trace_id opens the matching trace.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

k8s/prometheus/deployment.yaml

@@ -0,0 +1,86 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: prometheus
+  namespace: observability
+  labels:
+    app.kubernetes.io/name: prometheus
+    app.kubernetes.io/component: metrics
+    app.kubernetes.io/part-of: observability
+spec:
+  replicas: 1
+  strategy:
+    # ReadWriteOnce PVC: the old pod must release the volume first.
+    type: Recreate
+  selector:
+    matchLabels:
+      app: prometheus
+  template:
+    metadata:
+      labels:
+        app: prometheus
+        app.kubernetes.io/name: prometheus
+        app.kubernetes.io/component: metrics
+        app.kubernetes.io/part-of: observability
+      annotations:
+        prometheus.io/scrape: "true"
+        prometheus.io/port: "9090"
+    spec:
+      serviceAccountName: prometheus
+      securityContext:
+        runAsUser: 65534
+        runAsGroup: 65534
+        fsGroup: 65534
+      containers:
+        - name: prometheus
+          image: prom/prometheus:v3.14.0
+          args:
+            - --config.file=/etc/prometheus/prometheus.yaml
+            - --storage.tsdb.path=/prometheus
+            - --storage.tsdb.retention.time=15d
+            - --storage.tsdb.retention.size=8GB
+            - --web.enable-lifecycle
+            # Receives remote_write from Tempo's metrics_generator (span metrics + service graphs).
+            - --web.enable-remote-write-receiver
+            - --web.external-url=https://prometheus.sttlab.local
+            - --web.route-prefix=/
+          ports:
+            - name: http
+              containerPort: 9090
+          resources:
+            requests:
+              cpu: 100m
+              memory: 512Mi
+            limits:
+              cpu: "2"
+              memory: 2Gi
+          readinessProbe:
+            httpGet:
+              path: /-/ready
+              port: http
+            initialDelaySeconds: 10
+            periodSeconds: 10
+          livenessProbe:
+            httpGet:
+              path: /-/healthy
+              port: http
+            initialDelaySeconds: 30
+            periodSeconds: 30
+          volumeMounts:
+            - name: config
+              mountPath: /etc/prometheus
+            - name: data
+              mountPath: /prometheus
+            - name: librechat-metrics
+              mountPath: /etc/prometheus/secrets/librechat
+              readOnly: true
+      volumes:
+        - name: config
+          configMap:
+            name: prometheus-config
+        - name: librechat-metrics
+          secret:
+            secretName: librechat-metrics
+        - name: data
+          persistentVolumeClaim:
+            claimName: prometheus-data