diff --git a/monitoring/node-exporter-compute5-compose.yml b/monitoring/node-exporter-compute5-compose.yml
new file mode 100644
index 0000000..791fcc1
--- /dev/null
+++ b/monitoring/node-exporter-compute5-compose.yml
@@ -0,0 +1,21 @@
+# node-exporter - Host metrics exporter for Prometheus
+# Host: compute5 (192.168.99.196), Port: 9100
+
+services:
+  node-exporter:
+    image: prom/node-exporter:latest
+    container_name: node-exporter
+    restart: unless-stopped
+    pid: host
+    network_mode: host
+    volumes:
+      - /proc:/host/proc:ro
+      - /sys:/host/sys:ro
+      - /:/rootfs:ro
+      - /var/lib/node_exporter/textfile:/textfile:ro
+    command:
+      - '--path.procfs=/host/proc'
+      - '--path.sysfs=/host/sys'
+      - '--path.rootfs=/rootfs'
+      - '--collector.textfile.directory=/textfile'
+      - '--collector.filesystem.mount-points-exclude=^/(sys|proc|dev|host|etc)($$|/)'
diff --git a/monitoring/postfix-queue-check.sh b/monitoring/postfix-queue-check.sh
new file mode 100755
index 0000000..893a011
--- /dev/null
+++ b/monitoring/postfix-queue-check.sh
@@ -0,0 +1,28 @@
+#!/bin/bash
+# Postfix queue depth textfile metric — runs every 5 min via root crontab.
+
+TEXTFILE="/var/lib/node_exporter/textfile/postfix_queue.prom"
+HOSTNAME=$(hostname -s)
+TMPFILE=$(mktemp /tmp/postfix_queue.XXXXXX.prom)
+trap 'rm -f "$TMPFILE"' EXIT
+
+QUEUE_SIZE=0
+if command -v mailq >/dev/null 2>&1; then
+    # grep -c exits 1 on no match even for count=0; handle separately
+    QUEUE_SIZE=$(mailq 2>/dev/null | grep -c '^[0-9A-F]' 2>/dev/null) || QUEUE_SIZE=0
+fi
+
+cat > "$TMPFILE" << EOF
+# HELP postfix_queue_size Number of messages in postfix mail queue
+# TYPE postfix_queue_size gauge
+postfix_queue_size{host="${HOSTNAME}"} ${QUEUE_SIZE}
+# HELP postfix_queue_check_last_run_seconds Unix timestamp of last queue check
+# TYPE postfix_queue_check_last_run_seconds gauge
+postfix_queue_check_last_run_seconds $(date +%s)
+EOF
+
+mkdir -p "$(dirname "$TEXTFILE")"
+mv "$TMPFILE" "$TEXTFILE"
+chmod 644 "$TEXTFILE"
+trap - EXIT
+exit 0