CoreDNS

Prometheus Metrics

CoreDNS is a flexible, plugin-based DNS server commonly used as the default DNS provider in Kubernetes clusters.

Prometheus Metrics

Service Configuration

CoreDNS exposes Prometheus metrics through the prometheus plugin. Add it to your Corefile:

. {
    prometheus :9153
    forward . 8.8.8.8
    cache 30
    log
}

In many deployments (including Kubernetes), the prometheus plugin is already enabled by default on port 9153. Metrics are available at http://localhost:9153/metrics.

Glouton Configuration

Linux

sudo tee /etc/glouton/conf.d/99-coredns.conf > /dev/null << 'EOF'
metric:
  prometheus:
    targets:
      - url: "http://localhost:9153/metrics"
        name: "coredns"
        allow_metrics:
          - "coredns_dns_requests_total"
          - "coredns_dns_responses_total"
          - "coredns_dns_request_duration_seconds*"
          - "coredns_cache_hits_total"
          - "coredns_cache_misses_total"
EOF

Windows

Create or edit C:\ProgramData\glouton\conf.d\99-coredns.conf:

metric:
  prometheus:
    targets:
      - url: "http://localhost:9153/metrics"
        name: "coredns"
        allow_metrics:
          - "coredns_dns_requests_total"
          - "coredns_dns_responses_total"
          - "coredns_dns_request_duration_seconds*"
          - "coredns_cache_hits_total"
          - "coredns_cache_misses_total"

Glouton automatically detects configuration changes.

Customize collected metrics

The metrics below are our recommended defaults. You can adjust the allow_metrics list to include any metric from CoreDNS’s metrics plugin documentation, or use deny_metrics to exclude specific ones. See Metrics Filtering for details.

Metric	Description
coredns_dns_requests_total	Total number of DNS requests received
coredns_dns_responses_total	Total number of DNS responses sent
coredns_dns_request_duration_seconds	Histogram of DNS request processing durations in seconds
coredns_cache_hits_total	Total number of cache hits
coredns_cache_misses_total	Total number of cache misses