Dnsmasq DHCP

Plugin: go.d.plugin Module: dnsmasq_dhcp

Overview

This collector monitors Dnsmasq DHCP leases databases, depending on your configuration.

By default, it uses:

• /var/lib/misc/dnsmasq.leases to read leases.
• /etc/dnsmasq.conf to detect dhcp-ranges.
• /etc/dnsmasq.d to find additional configurations.

This collector is only supported on the following platforms:

• Linux

This collector only supports collecting metrics from a single instance of this integration.

Default Behavior

Auto-Detection

All configured dhcp-ranges are detected automatically

Limits

The default configuration for this integration does not impose any limits on data collection.

Performance Impact

The default configuration for this integration is not expected to impose a significant performance impact on the system.

Metrics

Metrics grouped by scope.

The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.

Per Dnsmasq DHCP instance

These metrics refer to the entire monitored application.

This scope has no labels.

Metrics:

Metric	Dimensions	Unit
dnsmasq_dhcp.dhcp_ranges	ipv4, ipv6	ranges
dnsmasq_dhcp.dhcp_hosts	ipv4, ipv6	hosts

Per dhcp range

These metrics refer to the DHCP range.

Labels:

Label	Description
dhcp_range	DHCP range in START_IP:END_IP format

Metrics:

Metric	Dimensions	Unit
dnsmasq_dhcp.dhcp_range_utilization	used	percentage
dnsmasq_dhcp.dhcp_range_allocated_leases	allocated	leases

Alerts

The following alerts are available:

Alert name	On metric	Description
dnsmasq_dhcp_dhcp_range_utilization	dnsmasq_dhcp.dhcp_range_utilization	DHCP range utilization

Setup

Prerequisites

No action required.

Configuration

File

The configuration file name for this integration is go.d/dnsmasq_dhcp.conf.

You can edit the configuration file using the edit-config script from the Netdata config directory.

cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config go.d/dnsmasq_dhcp.conf

Options

The following options can be defined globally: update_every, autodetection_retry.

Config options

Name	Description	Default	Required
update_every	Data collection frequency.	1	no
autodetection_retry	Recheck interval in seconds. Zero means no recheck will be scheduled.	0	no
leases_path	Path to dnsmasq DHCP leases file.	/var/lib/misc/dnsmasq.leases	no
conf_path	Path to dnsmasq configuration file.	/etc/dnsmasq.conf	no
conf_dir	Path to dnsmasq configuration directory.	/etc/dnsmasq.d,.dpkg-dist,.dpkg-old,.dpkg-new	no

Examples

Basic

An example configuration.

Config

jobs:
  - name: dnsmasq_dhcp
    leases_path: /var/lib/misc/dnsmasq.leases
    conf_path: /etc/dnsmasq.conf
    conf_dir: /etc/dnsmasq.d

Pi-hole

Dnsmasq DHCP on Pi-hole.

Config

jobs:
  - name: dnsmasq_dhcp
    leases_path: /etc/pihole/dhcp.leases
    conf_path: /etc/dnsmasq.conf
    conf_dir: /etc/dnsmasq.d

Troubleshooting

Debug Mode

Important: Debug mode is not supported for data collection jobs created via the UI using the Dyncfg feature.

To troubleshoot issues with the dnsmasq_dhcp collector, run the go.d.plugin with the debug option enabled. The output should give you clues as to why the collector isn't working.

• Navigate to the plugins.d directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on your system, open netdata.conf and look for the plugins setting under [directories].

  cd /usr/libexec/netdata/plugins.d/

• Switch to the netdata user.

  sudo -u netdata -s

• Run the go.d.plugin to debug the collector:

  ./go.d.plugin -d -m dnsmasq_dhcp

Getting Logs

If you're encountering problems with the dnsmasq_dhcp collector, follow these steps to retrieve logs and identify potential issues:

• Run the command specific to your system (systemd, non-systemd, or Docker container).
• Examine the output for any warnings or error messages that might indicate issues. These messages should provide clues about the root cause of the problem.

System with systemd

Use the following command to view logs generated since the last Netdata service restart:

journalctl _SYSTEMD_INVOCATION_ID="$(systemctl show --value --property=InvocationID netdata)" --namespace=netdata --grep dnsmasq_dhcp

System without systemd

Locate the collector log file, typically at /var/log/netdata/collector.log, and use grep to filter for collector's name:

grep dnsmasq_dhcp /var/log/netdata/collector.log

Note: This method shows logs from all restarts. Focus on the latest entries for troubleshooting current issues.

Docker Container

If your Netdata runs in a Docker container named "netdata" (replace if different), use this command:

docker logs netdata 2>&1 | grep dnsmasq_dhcp