<p>I've spent many hours over the past few days trying to understand why one of my pods can't reach a mysql service running in the cluster. I can provide service configs if necessary, but my debugging effort led me to check DNS using <a href="https://kubernetes.io/docs/tasks/administer-cluster/dns-debugging-resolution/" rel="nofollow noreferrer">this documentation</a>.</p>

<p>So from within a busybox pod running in my cluster, I tried the following command:</p>

<pre><code>nslookup kubernetes.default
</code></pre>

<p>And got the following:</p>

<pre><code>/ # nslookup kubernetes.default
Server:     10.7.240.10
Address:    10.7.240.10:53

** server can't find kubernetes.default: NXDOMAIN

*** Can't find kubernetes.default: No answer
</code></pre>

<p>Kube-dns is running</p>

<pre><code>$ kubectl get pods --namespace=kube-system -l k8s-app=kube-dns

NAME                        READY     STATUS    RESTARTS   AGE
kube-dns-5dcfcbf5fb-jgcxj   4/4       Running   0          20h
kube-dns-5dcfcbf5fb-t4wds   4/4       Running   0          20h
</code></pre>

<p>I'm not sure where to go from here. I would appreciate any help debugging or any documentation that might help.</p>

Tyler Jones
<p>It turns out I was too hasty to debug DNS, and the busybox bug mentioned by @Jukka threw me off.</p>

<p>Following the steps in the <a href="https://kubernetes.io/docs/tasks/debug-application-cluster/debug-service/" rel="nofollow noreferrer">Debug Services</a> docs, I was able to confirm that DNS is in fact working.</p>

<p>Will continue to investigate why my service is unreachable.</p>
