# Quadlet unit: node-exporter (rootless, boot-persistent).
#
# Install path on dankclaw: ~/.config/containers/systemd/node-exporter.container
# Unit name: node-exporter.service (container name: node-exporter)
#
# Host metrics source for Prometheus. This replaces the compose service of the
# same name in dankclaw/compose.yaml ("Observability" block).
#
# HOST NAMESPACE. It must run in the host network namespace to report the
# host's own interfaces/connections, and --pid=host for the processes and
# cgroups collectors. "localhost" inside the container is therefore the host's
# loopback, which is what the homepage status timer probes.
#
# LISTEN ADDRESSES. Until 2026-09-11 this bound :9100 on every interface. It
# now binds exactly two: loopback for the homepage status probe, and the LAN
# address because Prometheus — which runs in a container on dankclaw_default —
# scrapes http://192.168.0.143:9100 (shared/prometheus/prometheus.yml,
# job "node-dankclaw"). node_exporter itself has no authentication, so keeping
# the wildcard bind off the table matters: this is the second half of the
# pairing that removes the unauthenticated observability surface, and both
# consumers are accounted for. Dankserver runs its own copy of this container
# (scraped by the "node-dankserver" job) — since 2026-09-16 as a Quadlet unit in
# the same shape (dankserver/observability/quadlet/), because the compose-only
# version it replaced had been dead for a day and a half before anyone noticed.
#
# MOUNTS. The container reads the host's /proc, /sys and / as /host/* read-only
# and is pointed at them with --path.*; it writes nothing anywhere.

[Unit]
Description=Prometheus node exporter (Dankclaw host metrics)
After=network-online.target
Wants=network-online.target

[Container]
ContainerName=node-exporter
Image=docker.io/prom/node-exporter:latest
Network=host
PodmanArgs=--pid=host
Exec=--path.procfs=/host/proc --path.sysfs=/host/sys --path.rootfs=/rootfs --web.listen-address=127.0.0.1:9100 --web.listen-address=192.168.0.143:9100
Volume=/proc:/host/proc:ro
Volume=/sys:/host/sys:ro
Volume=/:/rootfs:ro
HealthCmd=wget --spider -q http://localhost:9100/metrics
HealthInterval=30s
HealthTimeout=10s
HealthRetries=3
HealthStartPeriod=30s

[Service]
Restart=always
RestartSec=10

[Install]
WantedBy=default.target