Prometheus Node Exporter

The Prometheus Node Exporter package runs the Prometheus node_exporter on the firewall. It serves host metrics, such as CPU, memory, file systems, network interfaces and load, on an HTTP endpoint that a Prometheus server scrapes. FreeSense adds a small collector that publishes each configured FreeSense interface with its name, description and enabled state. The 1.1.0 Stable repository ships FreeSense-pkg-node_exporter 0.18.1_10 with node_exporter 1.11.0.

Use it when you already run Prometheus (often with Grafana) and want the firewall in the same dashboards. For a push model, use Telegraf instead.

Install

1. Open System → Package Manager → Available Packages.
2. Find Prometheus Node Exporter (package FreeSense-pkg-node_exporter, category Monitoring, resource profile Lightweight) and choose Install.

The install pulls in node_exporter and python312, which runs the FreeSense interface collector. Stable packages are published for amd64 and, starting with 1.1.1, arm64.

On the first install the package saves default settings: the default collector set, port 9100 and extra flags --log.level=warn. It doesn’t start the exporter until you choose an interface and enable it.

Where to find it

Menu path	Page
Services → Prometheus node_exporter	/pkg_edit.php?xml=node_exporter.xml, a single settings page

First-time setup

1. Open Services → Prometheus node_exporter and check Enable node_exporter.

2. Choose the Interface that Prometheus reaches the firewall on, usually LAN or a management interface. WAN is not offered.

3. Keep Listen port at 9100 unless that port is taken.

4. Keep the default Collectors selection unless you need a specific extra collector.

5. Choose Save. The exporter listens on the interface’s IPv4 address, for example 192.168.1.1:9100.

6. Add a scrape job in Prometheus:

   scrape_configs:
     - job_name: freesense
       static_configs:
         - targets: ['192.168.1.1:9100']

7. Open http://192.168.1.1:9100/metrics from the Prometheus host to check the endpoint.

Settings reference

Field	What it does	Default
Enable node_exporter	Starts the exporter. When unchecked, the service stops and the rc script is removed.	unchecked
Interface	Interface whose IPv4 address the endpoint listens on. Required. WAN interfaces are hidden.	none
Listen port	TCP port of the metrics endpoint. Must be a valid port.	9100
Collectors	Collectors passed to node_exporter as --collector.<name> flags. Entries marked (*) form the default set: boottime, cpu, exec, filesystem, loadavg, meminfo, netdev, textfile and time. Others offered: buddyinfo, ntp, runit, supervisord, devstat.	default set
Extra flags	Additional command-line flags appended to the exporter’s arguments	--log.level=warn

Collector selection

Selecting a collector adds --collector.<name>, which turns it on. Deselecting a collector does not add --no-collector.<name>, so collectors that node_exporter enables by default keep running. To turn one off, add --no-collector.<name> under Extra flags. Some listed collectors (buddyinfo, runit, supervisord) are not built for FreeBSD or have been removed from current node_exporter versions. Selecting one of them can stop the exporter from starting.

Interface metrics added by FreeSense

A cron job runs /usr/local/share/FreeSense-pkg-node_exporter/interface-collector.py every minute at low priority. It reads /conf/config.xml and writes /var/tmp/node_exporter/freesense.prom for the textfile collector:

Metric	Labels	Value
node_freesense_interface_up	name (for example lan, opt1)	1 if the interface is enabled, else 0
node_freesense_interface_info	name, interface (device such as igc1), description	Same as above

Keep the textfile collector selected for these metrics.

Firewall rules and interfaces

• The endpoint listens on TCP 9100 (or your port) on the selected interface’s address.
• The endpoint has no authentication or TLS by default and reveals operational detail about the firewall. Allow it only from the Prometheus server: on the selected interface, add a pass rule under Firewall → Rules for TCP 9100 from the Prometheus host, and keep other sources blocked.
• If the selected interface has no IPv4 address, the generated listen address has no IP part (:9100), and the exporter listens on all addresses. Pick an interface with a static IPv4 address.

Service, logs, and status

Item	Value
Service	node_exporter in Status → Services
rc script	/usr/local/etc/rc.d/node_exporter.sh, a copy of the upstream /usr/local/etc/rc.d/node_exporter script
Settings for the rc script	/usr/local/etc/rc.conf.d/node_exporter (node_exporter_listen_address, node_exporter_args)
Textfile output	/var/tmp/node_exporter/freesense.prom

Package messages, such as a failed write of the rc.conf.d file, appear in the system log with the node_exporter prefix under Status → System Logs.

Upgrade, backup, and removal

• Settings are saved in config.xml under installedpackages/nodeexporter.
• Before removal, the package stops the service, deletes node_exporter.sh and the rc.conf.d file, and removes the interface-collector cron job. The settings stay in the configuration.
• After upgrading from 1.0, update dashboards and alerts: the FreeSense interface metrics are named node_freesense_interface_up and node_freesense_interface_info. The old node_pfsense_* names and the pfsense.prom file no longer exist.

Troubleshooting

• “You must select an interface to listen to”: choose an interface before saving.
• The service doesn’t start after a collector change: remove the collector you just added, especially buddyinfo, runit or supervisord, and save again.
• Prometheus can’t reach the endpoint: check the firewall rule on the selected interface and that the target uses that interface’s address, not another firewall address.
• Grafana panels for interfaces are empty after the upgrade: the queries still use node_pfsense_interface_*. Rename them to node_freesense_interface_*.

Changes in FreeSense 1.1

• The interface metrics are renamed to node_freesense_interface_up and node_freesense_interface_info and written to freesense.prom. The collector deletes the old pfsense.prom file, so node_pfsense_* series stop (freesense-packages 8312aa4).
• The menu entry is in the Monitoring group of the Services menu (4ae11df).
• The 1.1.0 Stable repository ships node_exporter 1.11.0, built for the FreeBSD 16.0-CURRENT base.