<p>I use DNS in kubernetes. and test result like:</p>

<pre><code>core@core-1-86 ~ $ kubectl exec busybox -- nslookup kubernetes
Server:    10.100.0.10
Address 1: 10.100.0.10

Name:      kubernetes
Address 1: 10.100.0.1
</code></pre>

<p>And then I entried to busybox container, and ping kubernetes, like:</p>

<pre><code>core@core-1-86 ~ $ kubectl exec -it busybox sh
/ # ping kubernetes
PING kubernetes (10.100.0.1): 56 data bytes
^C
--- kubernetes ping statistics ---
55 packets transmitted, 0 packets received, 100% packet loss
/ #
</code></pre>

<p>if I ping another ip , it ok!</p>

<pre><code>/ # ping 10.12.1.85
PING 10.12.1.85 (10.12.1.85): 56 data bytes
64 bytes from 10.12.1.85: seq=0 ttl=63 time=0.262 ms
64 bytes from 10.12.1.85: seq=1 ttl=63 time=0.218 ms
^C
--- 10.12.1.85 ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 0.218/0.240/0.262 ms
/ #
</code></pre>

<p>who can help me and tell me why?</p>

<p>The kubernetes service is a virtual IP and doesn't currently handle ICMP requests (see #<a href="https://github.com/kubernetes/kubernetes/issues/2259" rel="nofollow">2259</a>). You should be able to verify connectivity to the kubernetes service using a TCP connection, e.g. <code>curl https://kubernetes/</code>. </p>
