metrics

Metrics

By default, metrics are disabled and there is no metrics server.

You can however enable metrics reporting as described below.

Prometheus

To enable Prometheus metrics reporting, set METRICS_TYPE=prometheus.

The metrics will be reported by an HTTP server on port 9090.

💁 You can change that with METRICS_PROMETHEUS_ADDRESS=":9090".

If you have Prometheus running in a container in the same network as this DNS container (named dns), you can configure Prometheus to get the metrics data by adding

- job_name: 'dns'
  static_configs:
    - targets: ['dns:9090']

in your scrape_configs: block in your prometheus.yml configuration file.

Grafana

To visualize metrics, I recommend using Grafana.

You can import the dashboard I designed with the following steps:

1. In your Grafana web user interface, click on the import button:

   

2. Copy the JSON code from grafana.json

3. Paste the code in the panel JSON and click Load:

   

Metrics available

All the metrics exported will have the dns_ prefix.

💁 You can change that with METRICS_PROMETHEUS_SUBSYSTEM=dns.

The list of all metrics available is as follows:

Metric with prefix	Type	Dimensions	Description
dns_hostnames_filtered	Counter	class, type	DNS filtered out hostnames by question class and type
ips_filtered	Counter	type	IP addresses filtered out by response type
blocked_hostnames	Gauge		Total number of hostnames to be blocked by the DNS server filter
blocked_ips	Gauge		Total number of IP addresses to be blocked by the DNS server filter
blocked_ip_prefixes	Gauge		Total number of IP address prefixes to be blocked by the DNS server filter
cache_insert	Counter		DNS cache insertions
cache_insert	Counter		DNS cache insertions
cache_move	Counter		DNS cache move
cache_remove	Counter		DNS cache remove
cache_insertEmpty	Counter		DNS cache insertEmpty
cache_getEmpty	Counter		DNS cache getEmpty
cache_hit	Counter		DNS cache hit
cache_expired	Counter		DNS cache expired
cache_miss	Counter		DNS cache miss
cache_max_entries	Gauge	type	DNS cache maximum number of entries
cache_labels	Gauge		DNS cache labels
dns_dns_over_https_dials	Counter	url	DNS over HTTPS dials by URL
dns_over_tls_dials	Counter	provider, address, outcome	DNS over TLS dials by provider, address and outcome
dns_plaintext_fallback_dials	Counter	provider, address, outcome	DNS dials by provider, address and outcome
requests_received	Counter		Requests received by the server
questions_received	Counter	class, type	Questions contained in requests received by the server
response_rcodes	Counter	rcode	Response codes
answers_sent	class, type		Answers contained in responses sent by the server
responses_sent	Counter		Responses sent out by the server
requests_inflight	Gauge		Requests in flight in the server