# =============================================================================
# node-exporter (TASK-0135, phase-15) — DaemonSet, ns `monitoring`.
#
# EXPECTED-PRESENT infrastructure: the DiskUsageHigh alert (the spec's six)
# reads node_filesystem_usage, and the Infra dashboard's CPU/mem/disk panels
# need it. Without a node exporter those panels/alerts are silently empty.
# Decision (recorded in the TASK-0135 report): ship the daemonset so the
# spec's alert is actionable in staging, rather than leaving the alert
# permanently dead.
#
# hostPath mounts are read-only + hostNetwork for /proc, /sys, / mount — the
# standard node-exporter security profile (the container still runs
# non-root; /proc and /sys are world-readable).
# Image pinned: prom/node-exporter:v1.7.0 (the 1.7 line —
# node_filesystem_usage is a 1.x-era metric name; the v1.8+ image renamed
# nothing we use, but 1.7 is the line the alert's expr targets).
# =============================================================================
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: node-exporter
  namespace: monitoring
  labels:
    app.kubernetes.io/name: node-exporter
    app.kubernetes.io/part-of: ai-software-factory
spec:
  selector:
    matchLabels:
      app.kubernetes.io/name: node-exporter
  template:
    metadata:
      labels:
        app.kubernetes.io/name: node-exporter
    spec:
      hostNetwork: true
      hostPID: true
      containers:
        - name: node-exporter
          image: prom/node-exporter:v1.7.0
          imagePullPolicy: IfNotPresent
          args:
            - --path.procfs=/host/proc
            - --path.sysfs=/host/sys
            - --path.rootfs=/host/root
            - --web.listen-address=0.0.0.0:9100
            - --collector.filesystem.mount-points-exclude=^/(sys|proc|dev|host|etc)($$|/)
          ports:
            - containerPort: 9100
              name: metrics
          volumeMounts:
            - name: proc
              mountPath: /host/proc
              readOnly: true
            - name: sys
              mountPath: /host/sys
              readOnly: true
            - name: root
              mountPath: /host/root
              readOnly: true
              mountPropagation: HostToContainer
          resources:
            requests:
              cpu: 100m
              memory: 64Mi
            limits:
              cpu: 300m
              memory: 256Mi
          securityContext:
            allowPrivilegeEscalation: false
            # node-exporter runs as root by default; runAsNonRoot is not
            # possible for the /proc, /sys collectors without capabilities.
            # Recorded trade-off: the container is read-only + no privilege
            # escalation; only hostPath mounts it needs.
            seccompProfile:
              type: RuntimeDefault
      tolerations:
        # run on every node (incl. the control plane, so a single-node
        # staging cluster still gets node metrics)
        - operator: Exists
      volumes:
        - name: proc
          hostPath:
            path: /proc
        - name: sys
          hostPath:
            path: /sys
        - name: root
          hostPath:
            path: /