Hostlookuper periodically performs DNS requests, measures latency and exports the data as Prometheus metrics.
It can be used to continuously monitor a list of DNS servers and procotols, so
as to detect anomalies in the network early on. Lookup errors are logged, and
also accounted for in the hostlookuper_dns_errors_total metric.
Docker images are available on both registries:
docker.io/postfinance/hostlookuper
ghcr.io/postfinance/hostlookuper
hostlookuper is configured with the following arguments:
$ hostlookuper -h
Usage of hostlookuper:
-debug
enable verbose logging
-dns-servers string
comma-separated list of DNS servers. if the protocol is omitted, udp is implied, and if the port is omitted, 53 is implied (default "udp://9.9.9.9:53,udp://8.8.8.8:53,udp://one.one.one.one:53")
-hosts string
comma-separated list of hosts against which to perform DNS lookups (default "google.ch,ch.ch")
-interval duration
interval between DNS checks. must be in Go time.ParseDuration format, e.g. 5s or 5m or 1h, etc (default 5s)
-listen string
address on which hostlookuper listens. e.g. 0.0.0.0:9090 (default ":9090")
-prom-histogram
use Prometheus-compatible (le) histograms (default is false)
-timeout duration
maximum timeout for a DNS query. must be in Go time.ParseDuration format, e.g. 5s or 5m or 1h, etc (default 5s)| Path | Description |
|---|---|
/metrics |
Prometheus metrics |
/healthz |
Liveness probe — returns 200 OK |
/readyz |
Readiness probe — returns 200 OK |
An example /metrics response can be found in doc/example_metrics
A Grafana dashboard is available under doc/hostlookuper_grafana.json