Prometheus and Grafana

DNZ serves its counters at /metrics in the Prometheus text format. Prometheus scrapes them, Grafana graphs them, and the alert rules that come with DNZ tell you when something is off. You run Prometheus and Grafana wherever you like; they only need to reach DNZ. What is in there:

queries by source (local, cache, upstream, blocked…), response code, type and transport, and a latency histogram,
the cache: hits, misses, stale answers, prefetches, evictions,
every upstream’s health, round-trip time and failures,
blocked queries, RPZ hits, the per-client rate limit and response rate limiting,
DNSSEC validation results and the recursive resolver,
zone transfers, NOTIFY, secondary zones and dynamic updates,
certificate expiry, dnz-proxy nodes, Traefik, GeoDNS health checks and the Caddy/Traefik syncs.

Metrics are off by default.

Turn them on

Open Settings → General → Prometheus metrics, switch it on and pick where it is served:

	Own listen address	HTTP API
URL	`http://<address>/metrics`, e.g. port 9153	`/metrics` next to the dashboard and API, HTTPS when DNZ has a certificate
Token	Only once you make one	Always
Good for	A port only Prometheus can reach	One port for everything

Make a token creates a bearer token Prometheus sends with every scrape. It is shown once: copy it. A scrape without it, or with the wrong one, gets 401. The card then shows a scrape config for Prometheus, filled in with DNZ’s address as your browser reaches it (change it to the address Prometheus uses), and a curl line to check it from the Prometheus host. The same from the terminal:

dnz settings metrics on --addr 0.0.0.0:9153    # own listen address
dnz settings metrics --new-token               # printed once
dnz settings metrics --api on                  # also at /metrics on the HTTP API
dnz settings metrics                           # where it is served, the token

Or in the config file, which applies until the settings are saved in the dashboard or the CLI:

[metrics]
enabled = true
addr = "0.0.0.0:9153"
api = false
token = "a-long-random-string"

Without a token, anyone who reaches the own listen address can read the metrics (names of zones, upstreams, proxies and certificates are in the labels). Listen where only Prometheus can reach, or make a token.

Scrape it

Add a job to prometheus.yml on the Prometheus server. With a token, keep it in a file only Prometheus can read:

scrape_configs:
  - job_name: dnz
    scheme: http                       # https for the HTTP API behind TLS
    metrics_path: /metrics
    authorization:
      credentials_file: /etc/prometheus/dnz-metrics-token
    static_configs:
      - targets: ['dns1.example.internal:9153']

Several DNZ servers go into the same job, one target each. In a cluster, scrape every node: each serves its own counters (dnz_build_info carries its node id, dnz_cluster_leader and dnz_cluster_generation its place in the cluster), and metrics settings saved on one node reach the others within 15 seconds. Check it from the Prometheus host:

curl -s -H "Authorization: Bearer $TOKEN" http://dns1.example.internal:9153/metrics | head

Prometheus and Grafana with Docker Compose

DNZ’s repository has a compose file in deploy/monitoring/ that runs Prometheus (with DNZ’s alert rules) and Grafana (with the dashboard and the data source already set up) for a DNZ that runs elsewhere:

cd deploy/monitoring
cp .env.example .env        # set DNZ_TARGET, DNZ_METRICS_TOKEN and GRAFANA_PASSWORD
docker compose up -d

DNZ_TARGET is host:port as Prometheus reaches DNZ: the own listen address, or the dashboard’s address with DNZ_SCHEME=https behind TLS. Grafana is on port 3000 (user admin), Prometheus on 9090.

Grafana dashboard

Import deploy/grafana/dnz-dashboard.json (Dashboards → New → Import) and pick your Prometheus data source. The data source and the DNZ servers to show are variables at the top. It has rows for the overview (queries per second, cache hit ratio, SERVFAIL ratio, p95 latency, upstreams up, soonest certificate expiry), queries, cache and upstreams, filtering and rate limits, DNSSEC and recursion, zones and transfers, certificates and proxies, and the process.

Alert rules

deploy/prometheus/dnz-alerts.yml has rules for:

Alert	When
`DnzDown`	Prometheus cannot scrape DNZ
`DnzAllUpstreamsDown`, `DnzUpstreamDown`	Every upstream of a pool, or one upstream, is down
`DnzHighServfailRatio`	Over 5% of answers are SERVFAIL for 10 minutes
`DnzSlowAnswers`	Forwarded answers have a p95 over 500 ms
`DnzCertificateExpiringSoon`, `DnzCertificateExpiresVerySoon`	A certificate expires within 14 or 3 days
`DnzAcmeCertificateFailing`	Issuing or renewing an ACME certificate keeps failing
`DnzRateLimitingSpike`, `DnzResponseRateLimitingSpike`	Many queries over the per-client limit, or many answers limited by RRL
`DnzDnssecValidationFailures`	Answers keep failing DNSSEC validation
`DnzSecondaryZoneFailing`, `DnzSecondaryZoneExpiring`	A secondary zone cannot reach its primaries, or is about to expire
`DnzProxyNodeDown`, `DnzTraefikDisconnected`	A dnz-proxy node or a Traefik stopped reporting
`DnzHealthCheckFailing`, `DnzSyncFailing`	A GeoDNS health check, or a Caddy/Traefik record sync, fails
`DnzClusterNodeBehind`, `DnzClusterNoLeader`	A cluster node has not loaded the latest changes, or no node holds the leader lease

Add the file to rule_files in prometheus.yml. The rules expect the job to be called dnz.

Metrics reference

Every metric, with its labels, is listed in docs/metrics.md. A few to start with:

Metric	What it tells
`dnz_dns_queries_total{source,rcode,qtype,transport}`	Answered queries
`dnz_dns_request_duration_seconds{source}`	Latency histogram
`dnz_cache_hits_total`, `dnz_cache_misses_total`	Cache effectiveness
`dnz_upstream_up`, `dnz_upstream_rtt_seconds`	Upstream health and speed
`dnz_filter_blocked_total`	Blocked queries
`dnz_ratelimit_limited_total`, `dnz_rrl_responses_total`	Rate limiting
`dnz_dnssec_validations_total{result}`	DNSSEC validation
`dnz_certificate_expiry_timestamp_seconds`	Certificate expiry

Labels never carry query names or client addresses, so the number of series stays small; query types outside the common ones are counted as other.

Get started

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Prometheus and Grafana

Turn them on

Scrape it

Prometheus and Grafana with Docker Compose

Grafana dashboard

Alert rules

Metrics reference

​Turn them on

​Scrape it

​Prometheus and Grafana with Docker Compose

​Grafana dashboard

​Alert rules

​Metrics reference

Turn them on

Scrape it

Prometheus and Grafana with Docker Compose

Grafana dashboard

Alert rules

Metrics reference