Run DNS queries

With NodelocalDNS installed on your MKE cluster, you can run queries from the Pod that has the DNS diagnostic utilities.

  1. Run the Pod:

    kubectl apply -f https://k8s.io/examples/admin/dns/dnsutils.yaml

    Example output:

    pod/dnsutils created

  2. Verify that Pod status has changed to Running:

    kubectl get pods dnsutils

    Example output:

    NAME      READY  STATUS   RESTARTS  AGE
dnsutils  1/1    Running  0         26m

  3. Run the nslookup and dig DNS queries multiple times. The cache hits should increase for NodeLocalDnsCache.

    1. DNS query using nslookup:

      kubectl exec -i -t dnsutils -- nslookup example.com
kubectl exec -i -t dnsutils -- dig +short @169.254.0.10 example.com

      Example output:

      kubectl exec -i -t dnsutils -- nslookup example.com
Server:                10.96.0.10
Address:       10.96.0.10#53

Non-authoritative answer:
Name:  example.com
Address: 93.184.215.14

    2. DNS query using dig:

      kubectl exec -i -t dnsutils -- dig +short @169.254.0.10 example.com

      Example output:

      93.184.215.14

  4. Check the NodeLocalDNS metrics for cache hits:

    curl http://localhost:9253/metrics | grep coredns_cache_hits_total

    Example output:

     curl http://localhost:9253/metrics | grep coredns_cache_hits_total
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0# HELP coredns_cache_hits_total The count of cache hits.
# TYPE coredns_cache_hits_total counter
coredns_cache_hits_total{server="dns://10.96.0.10:53",type="denial",view="",zones="."} 8
coredns_cache_hits_total{server="dns://10.96.0.10:53",type="denial",view="",zones="cluster.local."} 71
coredns_cache_hits_total{server="dns://10.96.0.10:53",type="success",view="",zones="."} 8
coredns_cache_hits_total{server="dns://10.96.0.10:53",type="success",view="",zones="cluster.local."} 53
coredns_cache_hits_total{server="dns://169.254.0.10:53",type="success",view="",zones="."} 6
100 64055    0 64055    0     0  30.5M      0 --:--:-- --:--:-- --:--:-- 30.5M