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Dnsmasq DHCP

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 supported on all platforms.

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.

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.

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.

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.

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

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

Troubleshooting

Debug Mode

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

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